Shankar Abaji Bhise Biography

Who is Shankar Abaji Bhise?

Shankar Abaji Bhise was an Indian inventor, innovator and scientist who was entirely self-trained. He spent his childhood reading the Scientific American Magazines which were his introduction to the field of mechanical engineering. His big break came in the late 1890s when he won a trip to London.

Shankar Abaji Bhise’s famous inventions

It was during the early 1900s he produced his most innovative inventions – varying from kitchen gadgets to an automatically flushing toilet. He did so with the backing of Dadabhai Naoroji; who also had a long commercial career in England. Bhise’s most significant creation involved the printing press.


He created a prototype for the ‘Bhisotype’ – which would have had changed the printing industry. He was never able to bring together funds tomarket the Bhisotype. Despite falling into obscurity, he must be remembered for his innovative spirit, all while also supporting the freedom struggle in India.

Lal Bahadur Shastri Biography

Who was Lal Bahadur Shastri?

Lal Bahadur Shastri was the second Prime Minister of independent India, taking office after Jawaharlal Nehru. His popular slogan “Jai Jawan Jai Kisan” raised awareness about the importance of self-reliance and self-sustenance as the pillars of a strong nation.

Struggle for Independence

Shastri was inspired to join the struggle for independence after listening to a speech of Mahatma Gandhi’s in 1915. He was also well-read and followed the writings of foreign authors like Marx and Lenin. He later became the President of the Allahabad Congress Committee and played an important role in Gandhi’s Salt Satyagraha.

Second Prime Minister India

His methods of protest were civil and non-violent in nature. He believed that disobedience did not have to be violent in nature. Through these manners of protest, he was able to influence laws involving poverty, women’s rights and religious freedoms. After independence, he led India through the Indo-Pak war of 1965 successfully as Prime Minister.

Cecilia Payne Biography

Who is Cecilia Payne?

Cecilia Payne was an astronomer who discovered that stars were made of helium and hydrogen, thus changing the way astronomers understood the universe. It was previously believed that Earth, the Sun and stars were elementally very similar. Her work was initially rejected as it questioned long held beliefs in astronomy.

Education –

Payne studied astronomy at a time when there were very few women in the field. She began her journey when she was granted a scholarship to Cambridge University to study physics. After finding her options for the future limited, she moved to Harvard University and became the first woman to receive a PhD in Astronomy from Radcliffe College.

Research and Work –

Her analysis of variable stars laid the groundwork for all studies that have been conducted since. She showed a far greater understanding of the universe than most of her male counterparts at the time. Her work was rewarded when she became the first woman to Chair the Department of Astronomy at Harvard University.

The First Ever Real Black Hole Image

A black hole is an area in space which has a very strong field of gravity and as a result, light is unable to escape from it. Due to this, black holes are invisible. In order to observe them, telescopes are equipped with special instruments which observe the behaviour of material and stars surrounding black holes in order to detect their presence. Black holes are formed when a large star dies and collapses into itself. It is this compression of matter into a tiny space, which causes the strong field of gravity.

A black hole in the Messier 87 galaxy rose to fame when it became the first black hole to ever be captured on an image. Because light is unable to escape from black holes, it has been very difficult to capture them in an image.

The Event Horizon telescope is a project which links eight ground based radio telescopes which shared data in order to create the first image of the black hole. This data was collated by a team led by MIT graduate Katie Bouman – who created the algorithm to help translate the data into images.

London Eye Facts

What is the London Eye?

The London Eye is the world’s tallest cantilevered observation wheel, on the South Bank of the River Thames.

It was formerly known as the Millennium Wheel or the revolving observation wheel.

What is the height of the London Eye?

At a height of 443 feet(135 meters), the London Eye was the world’s tallest cantilevered observation wheel, before it was surpassed by the Star of Nanchang, in Nanchang, China.

Who built the London Eye?

The London Eye was originally conceived by David Marks and Julia Barfield of Marks Barfield Architects in 1993, in response to a competition organised by the Sunday Times and Great Britain’s Architecture Foundation. The competition was organised to build a new monument in London, to commemorate the new Millennium.

It was finally built by the architects themselves and was funded by British Airways, Tussauds Group and the architect couple themselves.

How long did it take to build the London Eye?

London Eye was constructed over a period of two years. Construction began in 1998 and it was inaugurated by the British Prime Minister, Tony Blair on December 31, 1999.

It admitted its first paying passenger until March 9, 2000.

4 Fun facts about the London Eye

1. The 32 capsules on the London Eye are representative of the 32 London boroughs and each one weighs as much as 20,000 pounds, approx But they are numbererd 1 to 33, avoiding the unlucky number 13.
2. The London Eye can carry 800 people each rotation.
3. The capsules travel at a pace of 26 cms per second, which is really slow.
4. The London Eye is not a ferris wheel, as it is supported by an A frame on just one side, and the carriages are outside the wheel rim instead of hanging low.

Muhammad Ali Biography

Who is Muhammad Ali?

Muhammad Ali was one of the most celebrated sportsperson of the 20th century. He is the first and only three time lineal World Heavyweight Champion.

Muhammad Ali was born as Cassius Clay and began training as a boxer at 12 years old. In a career that spanned almost 3 decades, Ali became one of the ‘Greatest’. His last fight was on December 11, 1981, with Trevor Berbick. He was a month short of his 40th birthday.

In 1984, he was diagnosed with Parkinson’s disease, sustained due to injuries to his head. He died on June 3rd, 2016, after several years as a philanthropist and a social activist. He won the Presidential Medal of Freedom in 2005.

Childhood and Early Life

Cassius Marcellus Clay, Jr, as Ali at birth was known as, was born on January 17, 1942 in Louisville, Kentucky. He had a sister and four brothers. He was named after his father Cassius Marcellus Clay, who was named after a Republican Kentucky politician. His father was a billboard painter and his mother Odessa O’Grady Clay was a domestic helper. They were descendents of African slaves and some mix of Irish and English ancestry.

Clay grew up among racial discrimination and racial segregation.

On one occasion he was upset about his bicycle being stolen, and was guided to take up boxing training, by a Louisville police officer, Joe E Martin.

Later Life and Career

Clay made his boxing debut in 1954, against local amateur boxer Ronnie O’Keefe. He went on to win six Kentucky Golden Gloves titles, two national Golden Gloves titles, an Amateur Athletic Union national title and the Light Heavyweight gold medal in the 1960 Summer Olympics, in Rome. He lost the 1960 Gold medal and it was replaced when he lit the torch, to open the 1996 Atlanta Olympics.

Marriage and Children

Muhammad Ali was married four times and had seven daughters and two sons.

Muhammad Ali’s Boxing Record

Muhammad Ali’s boxing career boasts 56 wins, 5 losses and 37 knockouts. He won the Heavyweight Championship 3 times between 1964 to 1979, which made him the title of ‘The Greatest’. He holds this title along with two others, Evander Holyfield (USA) and Lennox Lewis (UK)

  • 1964 Defeated Sonny Liston
  • 1974 Defeated George Foreman
  • 1978 Defeated Leon Spinks


Muhammad Ali was involved in several causes he felt close to. He worked tirelessly for racial equality for African Americans and also worked on several causes to promote peace and equality globally, including working towards national debt clearance of poverty stricken countries.

Awards and Achievements

He was honoured with a number of titles including, ‘the Greatest’, ‘Fighter of the Year’, ‘Sportsman of the Year’, ‘Sportsman of the Century’ and Sports Personality of the Century.

He received the Presidential Medal of Freedom(2005) and Presidential Citizens Medal(2009) for his contributions.

He was inducted in the International Boxing Hall of Fame. He is even honoured with a star on the Hollywood Walk of Fame.

5 Interesting facts about Muhammad Ali

  1. Ali was banned from boxing for 3 years due to his stance on the war in Vietnam.
  2. Ali had starred in a Broadway musical, recorded a spoken verse album, wrote poetry.
  3. Ali converted to Islam after his fight with Sonny Liston, in 1964.
  4. Muhammad Ali wrote two books, I am the Greatest and The Soul of a Butterfly

5 Super inspiring Muhammad Ali quotes

  1. If my mind can conceive it, and my heart can believe it – then I can achieve it.
  2. The best way to make your dreams come true is to wake up.
  3. Impossible is temporary. Impossible is nothing.
  4. It isn’t the mountains ahead to climb that wear you out; it’s the pebble in your shoe.
  5. It’s not bragging if you can back it up.

More information –

Meet the famous boxers from India – Vijender Singh and Mary Kom

What are Powers and Roots?

What is the power of a number

When a number is multiplied by itself either once or several times, the number of times the number is multiplied is known as the power of a number.

Example –
a) Multiplied by itself
5 x 5

b) Multiplied by itself multiple times
3 x 3 x 3

We can also write these numbers in a different way.
5 x 5 = 52
3 x 3 x 3 = 33
6 x 6 x 6 x 6= 64

What is an exponent, base and power in a number?

  • The small number at the top is the exponent. It is how many times the number is multiplied by itself.
  • The large number is called the base. It is the number that is being multiplied by it self.
  • The power of the number is how many times the number is being multiplied by it self.

How is the power of a number calculated?

The power of the number : 64 is
6 x 6 x 6 x 6 = 1296

The power of the number 72 is
7 x 7 = 49

What is the root of a number?

The root of a number A is another number, which when multiplied by itself a given number of times, equals A.
a) 5 x 5= 25
The number 5 is the root of twenty five.

b) 6 x 6= 36.
The number 6 is the root of the number 36.

How to calculate the root of a number?

Find the root of the number 16 :

Method –
16 is a small number – so it will be easy to figure out by multiplying small numbers by themselves:

1 x 1 = 1
2 x 2 = 4
3 x 3 = 9
4 x 4 = 16

So the root of the number 16 is 4.

Perpendicular Bisector: Definition & Theorem

What is a perpendicular bisector?

A perpendicular bisector of a line segment is a line that passes through the mid point of the line segment and is perpendicular to the line.

How do you draw a perpendicular bisector?

To draw a perpendicular bisector you need the following things :

Instructions :

  1. Draw a line of any length on a piece of blank paper.
  2. Insert the pencil in the compass and extend the compass so its points are more than half the length of the line.
  3. Put the pointy end of the compass down on one end of the line segment, then use the pencil inside the compass to draw an arc over the midpoint of the line segment on both sides of the line segment.
  4. Now, keeping the compass exactly the way it is, put the pointy end down on the other end of the line segment and draw two more arcs over the midpoint. You will see on both sides of the line: the arcs will intersect.
  5. Then take a ruler and draw a line between the two intersecting points that will pass through the line segment. This line is your perpendicular bisector.

Perpendicular bisector of a triangle

Perpendicular bisectors of triangles are drawn at each side of the triangle. Thus each triangle has three perpendicular bisectors. The point where the perpendicular bisectors of the triangle meet is known as the circumcenter of the triangle.

Perpendicular bisector theorem

  1. The theorem states that if a point is on the perpendicular bisector of a line segment, then that point is at an equal distance from both endpoints of the line segment.
  2. The converse of the perpendicular bisector theorem states that if a point is at an equal distance from both ends of a line segment, then that point lies on the perpendicular bisector of that line segment.

Why are perpendicular bisectors useful?

Perpendicular bisectors are useful in geometry, if we want to find a mid point of distances. This is necessary in architecture and study of mechanics and machinery and their construction.

Alcohols, Phenols and Ethers

Remember sometimes you go to a petrol pump and smell the petrol? Or if someone is cleaning the bathroom they pour a liquid and the liquid has a smell to it? Or when you go to the doctor when you are hurt and they apply a solution that feels cool when it is put on your skin. These things may contain chemicals that are known in chemistry as Alcohols, Phenols and Ethers.

What is an organic compound?

An organic compound is any compound which contains a carbon atom. Most oils, petrol and diesel and most molecules in living things are organic compounds.

What is hydroxyl group?

A hydroxyl group is an Oxygen atom attached to a Hydrogen atom.

What are alcohols?

An alcohol is when the Oxygen of the Hydroxyl group is also connected to the Carbon of an organic compound. Many alcohols are produced when the fruit is left alone for a few days and the bacteria eat the sugar inside the fruit. They use the sugar for energy and produce a waste that is usually alcohol.

Classification of alcohols

Alcohols are classified depending on the number of carbon atoms they contain.

  1. Methanol
  2. Ethanol
  3. Propanol
  4. Butanol
  5. Pentanol
  6. Hexanol

General formula of an alcohol

The General Formula of an alcohol is C(n)H(2n+1)-OH
Where “n”- Is the number of Carbon atoms

5 Uses of alcohols

Alcohols are used in a variety of ways,

  1. Alcohols are used in disinfecting the skin of a patient when they are injured or are about to be operated upon.
  2. Alcohols are used as fuel.
  3. Alcohols are also used as antifreeze to stop liquids from freezing in winter.
  4. Alcohols can also be used at preservatives.
  5. Alcohol is used as a solvent to dissolve chemicals, creating perfumes and more.

What are phenols?

Phenols are aromatic compounds- which means that when you smell phenols, they will give off a fruity smell.
Phenols are six carbon atom arranged in a circle with a Hydroxyl group attached to one of them.

General formula of a phenol

The formula of a phenol is C6H5-OH

Uses of phenols

Phenols are used in many cleaning agents when you clean floors and bathrooms, they are excellent at killing bacteria.
Phenol is also used in the production of cosmetics such as sunscreen and hair dye.

What are ethers?

Ethers are two Carbon atoms connected by an Oxygen Atom. These two carbon atoms could be part of larger compounds as well.

General formula of a ether

The general formula of a ether is C-O-C

Uses of ethers

Ethers are very interesting molecules because of their peculiar structure. They are used in Aerosol sprays, High Boiling Solvents and as a part of cosmetics.

Examples of ethers

Ethylene Oxide, Anisol and Diethyl ether are examples of ethers.

Recording Daily Weather

Why is it important to record daily weather?

Weather forecasting has been an important part of traditions in all civilizations for thousands of years. Farmers wanted to know the weather conditions for their crops, merchants needed favourable weather to begin their sea-voyages and even the common man wanted to know how the weather would be in the future. Since there were no modern tools to predict the weather, everyone looked for the signs in nature. Most of the times, the ancient people banked on old mythological proverbs and religious faiths.

When did modern weather forecasting begin?

Few hundred years ago, a naval officer named Robert FitzRoy came up with the idea of predicting the weather. He was deeply troubled by the massive loss of life at sea because of the extreme and unpredictable weather. He decided to set up an office in London where he used some basic equipment such as the barometer, nautical charts, and recorded patterns to predict the weather. As the telegraph network expanded in 1830s, FitzRoy could gather weather data from different coasts at his London office. If he thought a storm was around the corner, he immediately released a warning telegraph to the concerned port where a drum was raised to alarm the sailors. Though he had to face a lot of ridicule and mockery from the society, he continued working on weather predictions. Finally, in 1861, his forecasts started getting printed daily in ‘The Times’ newspaper of London. The first ever daily weather forecasts were published in The Times on August 1, 1861.

How do meteorologists forecast the weather?

Meteorology is the study of weather and the atmosphere. A meteorologist is a person who studies weather patterns and predicts how the weather would be in the future. All of you would have seen a meteorologist, or weather person, talking about weather on the news channels. Meteorologists gather information about the weather from satellites, balloons, and other instruments. They use powerful computers to analyse the collected data, and then, draw weather maps to predict the weather.

What are the different gadgets to predict weather?

  1. A Thermometer measures the air temperature. Thermometers are plain glass tubes containing liquids such as alcohol or mercury filled inside them. When air around the tube heats up the liquid, the liquid expands and rises up the tube. The readings on the thermometer then shows what the actual temperature is.
  2. A Barometer is a scientific device used by meteorologists to measure air pressure. When the barometer readings shoot up, it indicates sunny and dry weather, and when barometer readings fall down, it indicates rain and stormy weather.
  3. A Sling Psychrometer measures relative humidity.
  4. A Rain Gauge measures the amount of rain fallen over a time-period.
  5. A Wind Vane is an instrument that tells the direction of the wind.
  6. An Anemometer measures wind speed.
  7. Weather Maps show atmospheric conditions over a large portion of the Earth’s surface.
  8. A Hygrometer is a scientific instrument to measure the humidity in the air.
  9. A Weather Balloon measures weather conditions high up in the atmosphere.
  10. Weather Satellites are used to photograph and track large-scale air movements taking place over the Earth’s surface from the space.

Why is weather forecasting important?

There are several reasons why weather forecasts are important. Weather forecasting is a Science, that impacts the lives of many people. It forewarns the people about the future weather conditions so that people can plan their activities accordingly. It warns people about the impending severe weather conditions and other weather hazards such as thunder storms, hurricanes, and heavy rainfalls. Thus far, accurate weather predictions have been able to save the lives of many.

Are weather forecasts always correct?

Well, there has been a significant development in the technology of weather forecasting over the last 20 years. The weather forecast stations of today are much better equipped to provide advanced warnings of severe weather and save lives of many, but they are not always accurate. There is a lot of scope for improvement. Accurate weather forecasting requires powerful computers and lots of observational data collected from land, sea and air. A single weather station does not have the equipment to collect so much information and any major weather forecast is made only after a careful study of data received from thousands of stations across the globe. The other thing is that it is hard to predict the weather, as weather patterns are always changing.

8 Interesting facts about weather forecasting

  1. The first ever daily weather forecast was published in ‘The Times’ on August 1, 1861.
  2. If you love Math and Science, you too, can be a perfect meteorologist!
  3. There are some very interesting old proverbs that you can use to predict weather.
  4. Red Sky at Night, Sailor’s Delight. Red Sky in the Morning, Sailor’s Warning. This saying was used to warn the sailors about the weather conditions at the sea. If the sky was red at night, a fair weather could be expected and if the sky was red in the morning, it was a sign of a storm.
  5. Clear Moon, Frost Soon. The idea behind this saying was that a clear moon in the night sky meant frost in the morning.
  6. Cows Lying Down, Weather on the Way. The ancient farmers believed that when cows lied down on the ground, it was a sign of stormy weather and rain.
  7. Count the Cricket Chirps, Tell the Temperature. This proverb meant that any increase in the number of crickets in the area was a sign of increasing temperature.
  8. Ring around the Moon, Rain Real Soon- This meant that if you spot a ring around the moon, it would rain soon.

Classification of Plants

How are plants classified?

Plants are autotrophs and can make their own food through photosynthesis. Plants are classified based on their genetic and evolutionary relationship and form one of the five major kingdoms of classification.

Who came up with the classification system of organisms?

Carl Linnaeus, father of taxonomy is credited with creating the current system of classification of organisms in use today. In classification, the binomial nomenclature system is used and is in Latin.

It is divided into :

  • Kingdom
  • Division
  • Classification Order
  • Family
  • Genus
  • Species

What are the two main groups of plant classification?

Plants are classified into two main groups. This is a very basic way of classifying them.

I. Non Vascular Plants

  • Non vascular plants are known or thought to be the earliest living plants on the planet. They lack vascular tissues and wood that can give them structural support. They also lack true leaves, stem and roots that can help them transport water and nutrients. Because of this they are limited to a narrow range of habitats. The most common type of non vascular plants include the phylum Bryophyta.
  • The Phylum Bryophyta is a diverse group with over 10,000 plant species and consists of mosses, liverworts and hornworts.
  • Despite lacking some essential plant organs, bryophytes play an important role in minimising erosion along water bodies, carrying out water and nutrient cycling in forests and regulating temperature in permafrosts.
  • They reproduce through spores.

II. Vascular Plants

  • Vascular plants posses vascular tissue (xylem and phloem) that help them to transport water and minerals. They are also known as tracheophytes.

Vascular plants are divided into three main Phylum :

1. Pteridophytes

This phylum consists of over 12,000 species and over two thirds of them are tropical and consist of species of ferns and fern allies.

  • Pteridophytes are seedless plants. They reproduce using spores on the underside of their leaves. These are known as sporophylls. They do not flower or have seeds or cones for reproduction.
  • Pteridophytes have horizontal stems called rhizomes and simple leaves roots. The leaves are called fronds and unroll at maturity.
  • Pteridophytes have adapted to a wide range of habitat. They can be aquatic terrestrial and even cold resistant, but thrive in tropical regions.

2. Gymnosperms

Gymnosperms are thought to be some of the oldest living plants on the planet and exist in temperate and arctic regions. Members of this Phylum include pines, hemlocks, firs and spruce. The name gymnosperms means naked seed, which is exhibited by the presence of cones (or strobili) instead of seeds.

  • Gymnosperms are characterised by wood and green, needle like foliage.
  • Gymnosperms are considered to be heterosporous, that is they produce both male cones and female cones.

3. Angiosperms

Angiosperms are referred to as the flowering plants and is the most diverse Phylum with over 300,000 species, including trees, herbs, shrubs, bulbs, epiphytes(parasitic plants) and plants living in both marine and fresh water habitats.

  • Angiosperms are vascular seed plants, in which the ovule (egg) is fertilised and develops into a seed in an enclosed ovary.
  • The flower carry either the male reproductive system or the female or both.
  • The angiosperms have a very complex vascular tissue system and have adapted themselves to almost all types of temperatures and regions. They have developed extensive root systems and leaves that help them to absorb nutrients and make food for themselves.
  • Angiosperms have localised regions for plant growth called meristems and cambia. These two regions experience cell division for the regeneration or repair of a plant.
  • Angiosperms maybe either monocot or dicots.

What is the difference between monocot and dicot plants?





Monocotyledons or monocots have one cotyledon embryo.

Dicotyledons have two cotyledons embryo.


The veins in the leaf are parallel

The veins in the leaf are netlike(reticulated)


The vascular tissue bundles are arranged in a complex way.

The vascular tissue bundles are arranged in a ring.


Fibrous root system

Deep tap root system


Flowers parts in multiples of three

Flower parts in multiples of four or five.


Pollen with a single pore

Pollen with three pores


Secondary growth absent

Secondary growth present.

Examples of Monocotyledons

Banana, Orchid, Palm Tree, Sugar cane, Ginger, Onion, Rice, Wheat, Corn, Barley

Examples of Dicotyledons

Mangoes, Almonds, Beans, Peas, Pepper

Addition and Subtraction of Integers

What are Integers?

Integers are numbers that are not fractions such as 1,2,3… 45, 265 etc.
Fractions or numbers that also have parts of numbers are not integers.

For Example :
1.5, 2/3, ½, 23.21, 733.21 are not integers.

What do you do with Integers?

Integers can be added and subtracted to each other. They can also be divided and multiplied. But while doing so they have certain integer properties.

Properties of Integers

1. The Commutative Property of Integer Addition

If you are adding two or more integers to each other, they add up to the same answer, no matter what order you add them up in.
3 + 5 + 2 = 10
2 + 3 + 5 = 10
5 + 3 + 2 = 10
Each time it is the same answer!

2. The Commutative Property of Integer Multiplication

If you are multiplying two or more integers to each other, they add up to the same answer, no matter what order you add them up in.
3 x 5 x 2 = 30
2 x 3 x 5 = 30
5 x 3 x 2 = 30
Same answer each time!

3. The Associative Property of Integer Addition

Even if you group the integers in different ways and then add them, they will have the same answers.
(3 + 5) + 2 = 8 + 2 = 10
(2 + 3) + 5 = 5 + 5 = 10
5 + (3 + 2) = 5 + 5 = 10
And again, same answer!

4. The Associative Property of Integer Multiplication

Even if you group the integers in different ways and then multiply them – they will have the same answers.
(3 x 5) x 2 = 15 x 2= 30
(2 x 3) x 5 = 6 x 5 = 30
5 x (3 x 2) = 5 x 6= 30
Same answer!

5. The Distributive Property of Integer Addition and Multiplication

The distributive property of Integer Addition happens when you are multiplying integers with a group of integers you have added together. For example :
4 x (2 + 5) = ?
In this case, you have to follow the distributive law which states that each integer inside the brackets is multiplied to each integer outside the brackets.
4 x (2 + 5) = (4 x 2) + (4 x 5)
6 x (7 + 9) = (6 x7) + (6 x 9)

What are Positive Integers and Negative Integers?

Positive integers are all the integers that are greater than 0
+1, +2, +3, +4, …. +254 are all positive integers.
Usually when we write down positive integers we do not use the ‘+’ sign and this includes numbers in infinity.
Negative integers are all the integers that are less than 0
-1,-2,-3…. -254 are all negative integers

Rules for adding Integers

A positive integer when added to another positive integer is always going to be another positive integer.
(+4) + (+24) = (+28)
A negative integer when added to another negative integer will always result into another negative integer
(-13) + (-4) = -17

Rules for subtracting Integers

When a negative integer is subtracted from a positive integer, you need to change all the ‘-’ signs to ‘+’.
5 – (-6) =?
Does the sign change here?
– (-6) = + (+6)
Now use the same rules for addition :
5 – ( -6) =
(+5) + (+6) = 11

Floatation and Relative Density

What is floatation?

Floatation is the phenomenon of any substance or object resting on the surface of a liquid, without sinking.

The following are some floatation examples :

  • A plastic bottle floats on water.
  • A piece of wood floats on water.
  • Oil drops floating on water.

Why does an object float?

An object floats because of the differences in density of the object and the medium which is mainly liquid.
If a substance is denser than a liquid, it will sink. If a substance is less dense than the liquid it is put into, it will float.

What is density of a substance?

Density is the weight of a substance per unit volume. You can define the density of water by saying how many kilograms a liter of water or kerosene or any other substance weighs.
Another way of calculating density is by looking at the Relative Density of a substance. Which defines how dense a substance is, compared to another substance.

For example :
Mercury is 13.6 times denser than water. So if one liter of water weighs roughly one kilogram, one liter of mercury would weigh 13.6 kilograms.

What is the formula for Relative Density?

The formula for Relative Density (RD) is :
RD = (Weight of any volume of a substance) / (Weight of an equal amount of water)

Example :
500 ml of citric acid (lemon juice) weighs 800 grams. If 500 ml of water weighs 500 grams. What is the relative density of citric acid?

Solution :
RD = Weight of 500 ml Citric Acid/Weight of 500 ml Water
RD = 800/500
RD = 1.6
The Relative Density of Citric Acid with respect to Water is 1.6

The Relative Densities of some common substances are given below :

Relative Density of Water1
Relative Density of Soil2
Relative Density of Mercury13.6
Relative Density of Sand,2.65
Relative Density of Silver10

Antarctica’s Shrinking Iceberg

Thousands of years ago, most of Europe, Asia, North and South America was covered by huge sheets of ice, each several kilometres thick, but today, the only ice sheets on the Earth are found in Antarctica and Greenland. In this article, we will talk about Antarctica. It is a continent at the South Pole, located at the bottom of the globe. The continent remains frozen throughout the year because of extremely cold weather. Scientists believe that more than 90% of the ice found on the whole planet is in Antarctica. Today, Antarctica is changing fast because of the ongoing climate change.

What is climate change?

Climate change is what happens when our actions affect the Earth’s atmosphere. Our indiscriminate usage of the earth’s resources have caused drastic changes in global temperatures and weather. You would have noticed that the summers are becoming warmer, with temperatures soaring as high as 50 degrees Celsius and winters too are becoming more unbearable than before. All of this is a result of climate change, and we are directly responsible for it.

What is global warming?

Global warming is the rise in the temperature of the Earth. The harmful gases that are released from the vehicles and factories go up into the air. These gases are known as greenhouse gases and some of these gases trap heat and make the whole planet warmer. Deforestation or removal of the green cover of the Earth also contributes to global warming. Global warming does not just mean one day of hot weather. It means a slow but steady rise in the temperature over many, many years. Deforestation also contributes to global warming.

Let us explain to you in a little more detail. The Sun naturally warms up the Earth through its atmosphere, and the excessive heat from the Earth is reflected into space. Generally, the temperature on the Earth remains perfectly regulated by its atmosphere, but the presence of too many greenhouse gases makes the atmosphere thick and causes a ‘green house’ effect. The excessive heat from the sunlight gets trapped within the Earth’s atmosphere, leading to a rise in temperature. The ice in Antarctica is not supposed to melt, but because of global warming, it is melting a little bit more every year.

What are icebergs and glaciers?

Glaciers are made up of a large chunk of snow and ice and are found in Antarctica. An iceberg is a piece of glacier that breaks off from it because of the rise in temperature. Icebergs are made of fresh water and can float on sea water.

Are icebergs breaking away from the glaciers in Antarctica?

According to a NASA satellite, a large iceberg broke off from the Antarctic glaciers in July 2017. If the icebergs keep breaking off from the glaciers and begin melting, this will lead to a noticeable and dangerous rise in the sea-levels across the globe.

What are the harmful effects of climate change?

Changes in climate lead to serious natural disasters such as cyclones, earthquakes and tsunamis. This will lead to flooding of the low-lying areas and loss of vegetation and wildlife. Some of the major U.S. cities like Boston, Miami and New York are more likely to be flooded first. Many islands near the South Pacific Ocean and the Indian Ocean will be buried under the water. The number of people displaced could be well-imagined.

Icebergs also act like a mirror; they reflect the sunlight and thereby help in keeping the Earth’s temperature under control. If they disappear, the Earth will become warmer and many harmful climate changes would take place.

You CAN Help!

You would be thinking that since the problem is so big, there is hardly anything that you can do to help, but this is not the case. Each one of you who is reading this article can help in preventing this crisis.

Here is your list of do’s and don’ts to reduce climate change

  • Remember the three Rs-Reduce, reuse, recycle. Reduce the use of non-renewable fuels and things that consume more power. Try to reuse your old things. You can also give away your old clothes and toys to the needy children. Be creative, make an effort to come up with ideas to make new things out of the old. Try to put everything back into use.
  • Plant more trees.
  • Use energy saving CFLs in your house instead of bulbs and tube lights.
  • Use electrical appliances in your home wisely.
  • Turn off the lights and electrical appliances when not in use
  • Save water in the washroom.
  • Instead of going out in your car, prefer to use your cycle, or any means of public transport.
  • Let us prevent any further climate change, reduce our carbon footprint and adopt an eco-friendly lifestyle, starting TODAY!

Fact sheet on climate change

  1. As per the scientists, the global sea level rise has increased from 2.2mm each year in 1993, to 3.3mm each year in 2014.
  2. The average global temperature on the Earth has increased about 0.8° Celsius (1.4° Fahrenheit) since 1880.
  3. According to a research study, global warming will increase the Earth’s average temperature by 2-11 degrees Fahrenheit by the year 2100.
  4. Small icebergs weigh hundreds of tonnes and the big icebergs may weigh about billions of tonnes.
  5. Smaller icebergs are known as bergy bits and growlers. They are especially dangerous for ships because it is difficult to spot them.
  6. The famous ship Titanic sank after hitting an iceberg.
  7. Greenhouse gases mainly comprise of carbon dioxide, methane, nitrous oxide and chlorofluorocarbons (better known as CFCs).

History of Renaissance

What does Renaissance mean?

The Renaissance was a period in European history from the 14th century to the 17th century. The word Renaissance means rebirth. It was a rebirth in the sense that the period was a connecting period between the Middle Ages and Modern Ages in European history, though it is closely associated with Florence, Italy.

Why is the Renaissance important?

The Renaissance is important because it signalled the beginning of change in the thinking of European Christianity and so the perception of Man, Church and God changed too. This changed art, literature and architecture also.

The seeds of Renaissance were sowed post the Black Death, the plague which wiped out millions of people in Europe, between 1346 and 1353. This caused the economy to change as well.

Why did the Renaissance start?

The Rennaisance started with the decline in the powers of the Roman Catholic Church. The humanists emerged who believed that individuals had important contributions to make in the world, rather than that, the only ideas were of the Church.

How did Renaissance affect science, arts and literature?

  • During Renaissance, science, arts, architecture, philosophy and literature underwent a transformation in techniques and thought. Man became the measure of all things, as earlier stated by the Greek Philosopher Protagoras(490 BC to 420 BC). Some of the Renaissance thought patterns did reflect the early Greek and Roman philosophies. Renaissance art and philosophies brought human emotions into focus.
  • Renaissance art did not reject Christianity. However, there was a subtle shift in how intellectuals approached religion and other cultural areas of life. Printing was also discovered during this period.
  • During the Renaissance, art and money went hand in hand. The church was one the patrons apart from wealthy noblemen, who were businessmen.

Leonardo da Vinci’s contribution to the Renaissance period

Leonardo da Vinci’s brilliance crossed multiple disciplines, that he was referred to as the Renaissance man. Apart from the Mona Lisa and The Last Supper, two works of art he is famous for, he also did extensive studies and invented various machines and also surgery.

Leonardo da Vinci also created the map of the anatomical proportions of the human body, a very important study based on the notes of the architect Vitruvius. The defining of man as the measure of all things, the essence of Renaissance is reflected in this.

The Renaissance Timeline

  1. 1346   Bubonic plague begins
  2. 1350   Renaissance begins
  3. 1413   Brunelleschi creates Linear Perspectives in Art
  4. 1429   Joan of Arc and the Siege of Orleans
  5. 1439   Johannes Gutenberg invented the printing press
  6. 1464   Cosimo de Medici dies (Banker and Wealthy Florentine, also one of the most important patrons of Renaissance artists)
  7. 1478   The Spanish Inquisition
  8. 1486   Botticelli paints the Birth of Venus
  9. 1492   Christopher Columbus landed in the Caribbeans
  10. 1495   Leonardo da Vinci paints The Last Supper
  11. 1510   Raphael paints the School of Athens Fresco
  12. 1512   Michaelangelo paints the Sistine Chapel
  13. 1514   Machiavelli writes the Prince
  14. 1514   Thomas More writes The Utopia
  15. 1517   Martin Luther creates the theses for the birth of Protestantism
  16. 1559   Coronation of Queen Elizabeth the First.

Who were the important artists of the Renaissance?

Some of the important artists of the Renaissance are :

  1. Giotto di Bondone
  2. Leonardo da Vinci
  3. Michaelangelo Buonarroti
  4. Raphael Urbino
  5. Donatello
  6. Titian
  7. Sandro Botticelli
  8. Albrecht Dürer
  9. Michelangelo Merisi da Caravaggio
  10. Filippo Brunelleschi
  11. Hieronymus Bosch

Helen Keller Biography

Who was Helen Keller?

Helen Adams Keller was an American author, political activist and lecturer. She was the first deaf – blind person to earn a Bachelor of Arts degree. After graduating from Radcliffe, she went on to become one of the most influential people in the 20th Century. She worked for the rights of persons with disabilities, women and under privileged sections of society.

Early Life

Helen Keller was born a normal child in Tuscumbia, Alabama on June 27, 1880. She lost her hearing and sight at 19 months of age to what is now diagnosed as scarlet fever. Five years later, her parents, on Alexander Graham Bell’s advice, applied to hire a teacher from the Perkins Institute for the Blind, in Boston.

Helen Keller and Anne Sullivan

Anne Mansfield Sullivan was able to bring about an extraordinary transformation in Helen’s isolated world. She taught Helen to understand and communicate with the world around her. She went on to acquire an excellent education and become an important spokesperson for the blind and the deaf. Anne Sullivan taught Helen to read and write in Braille and hand signals of the deaf mute, which she could understand by touch. Her efforts to speak later on in life, were not as successful, when she went on to become a public figure, but she was able to make herself be understood.

Parents and Family

Helen Adams Keller’s father Arthur H Keller, was an editor for the Tuscumbia North Alabamian and had served as a captain for the Confederate Army. Her mother Kate Adam’s father was Charles W Adams, a Confederate general, in theAmerican Civil War.

Helen had two siblings, Mildred Campbell and Philip Brooks Keller, and two older half brothers from her father’s prior marriage, James and William Simpson Keller.

Education and Achievements

Helen Keller started attending the Perkins Institute for the Blind in May, 1888. Anne Sullivan and Helen Keller moved to New York to attend the Wright – Humason School for the Deaf, and to learn from Sarah Fuller at the Horace Mann School for the Deaf. In 1896, they returned to Massachusetts and Helen entered The Cambridge School for Young Ladies before gaining admittance to Radcliffe in 1900.

She became the first deaf blind person to earn a Bachelor of Arts degree, at the age of 24 in 1904.

Helen Keller was determined to communicate with others and she learned to speak. She spent much of her life giving lectures and speeches. She learned to read lips with her finger tips, so she could ‘listen’ to other people’s speeches.

She is known for her strong support for people with disabilities. She travelled to over 25 countries, giving lectures and motivational speeches about deaf people’s conditions.

Political and Social Activism

Apart from this, she was a woman’s rights activist, a political activist, a social activist and a pacifist. She also helped set up several foundations for the various causes she believed in, like the Helen Keller International organisation, along with George A Kessler, and it is devoted to research in vision, health and nutrition.

She also helped to found the American Civil Liberties Union (ACLU).

Writings and Literary Career

Helen Keller wrote a total of 12 published books and several articles.

Books by Helen Keller

  • The Frost King
  • The Story of My Life
  • The World I Live In
  • Out of the Dark
  • My Religion, later revised and published as Light in My Darkness
  • and many more

Later Years

Helen Keller suffered several strokes in 1961 and spent the last years of her life at home. She spent much of her time raising funds for the American Foundation for the Blind. She died in her sleep on June, 1968, at her home, ‘Arcan Ridge’, located in Easton, Connecticut, a few days short of her 88th birthday. She is buried at the Washington National Cathedral in Washington, DC.

6 Interesting facts about Helen Keller

  1. Helen Keller is Perkins School for the Blind’s most famous student
  2. She was nominated for the Nobel Peace Prize, in 1953
  3. Helen Keller and Anne Sullivan worked for 5 years in vaudeville to supplement their income. She was promoted as the 8th Wonder of the World and told her life’s story
  4. Although blind and deaf, Helen was very political and had very intelligent and strong opinions
  5. She was great friends with the writer Mark Twain and inventor Graham Bell
  6. Helen’s first word was ‘water’, when she understood the connection between the feeling of water running on her hand and Anne Sullivan described the word on her hand. She quickly demanded to learn as many words as possible. Anne Sullivan herself was visually impaired.

Awards and Honours

  • She was awarded the Presidential Medal of Freedom in 1964
  • Ranked one of the 100 most influential person of the 20th Century, according to TIME magazine
  • A commemorative stamp was issues by the US Postal Service in 1980
  • The state of Alabama issued a quarter with Helen Keller on it, during the US Mint’s commemorative 50 State Quarters Program
  • She was inducted into the Alabama Women’s Hall of Fame

3 Famous quotes by Helen Keller

  1. ‘The best and most beautiful things in the world cannot be seen or even touched. They must be felt with the heart.’
  2. ‘Character cannot be developed in ease and quiet. Only through experience of trial and suffering can the soul be strengthened, vision cleared, ambition inspired, and success achieved.’
  3. ‘Your success and happiness lies in you. Resolve to keep happy, and your joy and you shall form an invincible host against difficulties.’

Tokyo Facts and Information

Where is Tokyo?

Tokyo is the capital of Japan. It is one of the most populous city in the world with a population of 13.5 million. It is situated in the Kanto region, on the southeastern side of the main island Honshu and includes the Izu Islands and Ogasawara Islands. It is the seat of the Emperor of Japan and the Japanese Government.

Who founded Tokyo?

Tokyo was formerly known as Edo. Edo means estuary in Japanese. It had been the de facto seat of the government since 1603 when Shogun Tokugawa Ieyasu seized power. He was one of the three unifiers of Japan.

In 1868, with the arrival of Emperor Meiji, the name was changed to Tokyo. In 1943, the prefecture of Tokyo and Tokyo city were merged to form the Tokyo Metropolis.

What is Tokyo’s culture like?

Tokyo’s culture is a mix of the traditional and the new. The contemporary culture boasts of anime, fashion, design, high end robotic electronics and pop culture.

The traditional culture and rituals of Tokyo have been carried from the Edo period. The different districts in Tokyo have their own cultural backdrop. Performing arts such as Kabuki – za, Noh, Rakugo, the making of ukiyo-e prints, the writing of the short haiku poetry, tea ceremonies, all form a part of Tokyo’s cultural backdrop.

Tokyo also has beautifully landscaped gardens, streets lined with cherry blossoms, buddhist shrines and people enjoy dressing in the traditional kimono. The people of Tokyo honour omotenashi, the Japanese sincerity in showing hospitality to visitors.

Which are the famous heritage places to visit in Tokyo?

  1. The Imperial Palace, in the Marunouchi district, was built in the Edo period. It is still in use by Imperial family.
  2. Sensō-ji Temple, in the Asakusa district of Tokyo, is a shrine built for the Buddhist Goddess of Compassion, Kannon. It dates back to 645 AD.
  3. Ueno Park and Zoo, is the largets green space in Tokyo. The zoo was opened in 1882.
  4. The National Museum of Tokyo, has impotant Japanese and Chinese artworks and artefacts dating from 7th to 14th centuries.
  5. The Meiji Shrine, dedicated to the Emperor Meiji and his wife, Empress Shoken, was built in 1915. Destroyed in WW2, it was rebuilt in 1958.

12 Fun Tokyo facts you should know!

  1. Tokyo Metropolis has its own flag, which was adopted in 1964.
  2. It is the largest urban clustering of economy. It hosts 51 of the Fortune 500 companies.
  3. It is host to the 2020 Summer Olympics and Paralympics.
  4. Tokyo has capsule hotels, that are the size of a large refrigerator and have televisions, wifi and an electric console.
  5. Tokyo is made of 23 different wards or metropolitan areas or districts which are all distinct. And all districts are referred to as city!
  6. Tokyo is home to 14 Michelin three star restaurants.
  7. Tokyo’s Ritz Carlton has one of the most expensive rooms in the world, at USD 20,000.
  8. Shibuya Crossing is one of the busiest street crossings in the world. Around 2500 people cross at any given time.
  9. The Tokyo Tower is a communications and observation tower, in the Shiba-koen district of Minato, Tokyo, Japan. It is inspired by the Eiffel Tower and built in 1958.
  10. The Tokyo Skytree is a 634 meter tall broadcasting and observation tower built in 2012 and is in the Sumida district.
  11. Tokyo is famous for it’s varied cuisine, which include Ramen, Okonomiyaki, Udon, Sushi, Yuba, Soba, Tempura, Gyoza, Yakiniku.
  12. The National Museum of Western Art, built by the Swiss architect, Le Corbusier has works by some of the finest European artists like Rodin, Paul Cezanne, Claude Monet, Edouard Manet and Degas from the collection of the Japanese businessman Kojiro Matsukata.

Note: Don’t forget to check out Interesting Facts about Japan.

Nuclear Fission and Nuclear Fusion

Nuclear Fission and Nuclear Fusion are reactions which convert matter into energy.

What is matter?

The world you see around us has many things and all of this is made up of matter. Matter is anything and everything in the universe that occupies space.

What is the relationship between matter and energy?

The matter is made up of energy. Energy is what makes us do work.

What is nuclear fusion?

  • When matter fuses together to release energy, that is nuclear fusion.
  • All matter is made up of molecules, molecules are made up of atoms and atoms have a nucleus and electrons.
  • The Sun produces sunlight through nuclear fusion.
  • Inside the sun- where it is very hot, the nucleus of one atom and the nucleus of another atom come together and become one. A little bit of matter is left out- that little bit of matter is converted into a lot of energy.

What is nuclear fission?

  • Nuclear Fission is the process through which energy is created in nuclear power plants. It is also how nuclear bombs work.
  • In nuclear fission, the nucleus of an atom breaks into two or more nuclei (plural for nucleus). When the nucleus breaks, some matter is lost, this small amount of matter is converted into a large amount of energy. These broken nuclei then go and bombard other nuclei , those nuclei then break into more nuclei and this process can go on and on releasing a tremendous amount of energy.

Winter Olympics Facts

What is the Winter Olympics?

The Winter Olympics, officially known as the Olympic Winter Games, is a major international sporting event that takes place once every four years and is practiced on snow and ice.

The first Winter Olympics took place in 1924, in Chamonix, France.

How did the idea for Winter Olympics come about?

The idea for the Winter Olympics first came about in 1901, when the Nordic Games were held in Sweden. This gave birth to the idea for the Winter Olympics. Pierre de Coubertin, the founder of the Summer Olympics tried to add figure skating to the earlier Olympics, but had been unsuccessful, till 1908.

What are the official competitive categories of the Winter Olympics?

  • Alpine Skiing
  • Biathlon
  • Bobsleigh
  • Cross-country Skiing
  • Curling
  • Figure Skating
  • Freestyle Skiing
  • Ice Hockey
  • Luge
  • Nordic Combined
  • Skeleton
  • Ski Jumping
  • Snowboarding
  • Speed Skating

How are venues for the Winter Olympics decided?

The National Olympics Committees, created in 1894, selects from within their national territory cities to put forward bids to host the Olympics.

Which country has the most gold medals in the Winter Olympics?

Norway has the most gold medals.

Where is the 2018 Winter Olympics taking place?

The 2018 Winter Olympics, known as the PyeongChang 2018, is taking place in Pyeongchang County, South Korea, between 9th February, 2018 to 25th February, 2018.

4 Fun facts about the PyeongChang 2018 Winter Olympics

  1. The mascot for the PyeongChang 2018 is a white tiger named Soohorang and Bandabi, an Asiatic black bear.
  2. Pyeongchang is the smallest city to host the Olympics since 1994.
  3. The slogan for the PyeongChang 2018 Winter Olympics is ‘Passion. Connected’.
  4. A pentagonal, 35,000 seat Olympic stadium has been created in Pyeongchang. It will only be used for the opening and closing ceremonies and will be torn down after the games.

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What is Antarctic Circle?

The Antarctic circle is depicted as a red line at the bottom of the globe. It is actually an imaginary line placed to the south of the Equator.

Where is the Antarctic Circle located?

This special line of latitude is approximately 66¹/₂ degrees south of the equator and outlines the chilly southern zone of the world.

What’s inside the Antarctic Circle?

The continent of Antarctica lies within the Antarctic Circle. Antarctica is bigger than Europe and almost double the size of the continent of Australia. It remains covered in 99% ice almost throughout the year and because it experiences hardly any rain, scientists often refer to it as a desert. Antarctica has very little flora and fauna to boast of because of the harsh climatic conditions, but you would find some interesting animals such as penguins, whales seals, albatrosses, skua, snow petrel and krill.

Why is the Antarctic Circle important?

It helps the scientists in the study of the seasonal behaviour of the sunlight. It shows direct and indirect angles of sunlight.

What countries are in the Antarctic Circle?

There are no cities or villages in Antarctica. However, the countries nearest to the Antarctic circle are South Africa, Australia, New Zealand, Chile and Argentina.

What oceans does the Antarctic Circle touch?

Only the Southern Ocean passes through the Antarctic circle.

6 Interesting facts about Antarctic Circle

  1. The name ‘Antarctica’ comes from a Greek word meaning ‘opposite to the north’.
  2. The coldest temperature ever recorded on the Earth was in Antarctica on July 21, 1983, when it dipped 128 degrees below zero!
  3. All areas in the Antarctic Circle have twenty-four hours of daylight on the Summer Solstice in December.
  4. All areas in the Antarctic Circle have twenty-four hours of night in June on the Winter Solstice.
  5. The South Pole is in the center of the Antarctic Circle.
  6. There is no permanent population on the Antarctic Circle. Different countries have their research centres based in Antarctica where their team of scientists stay for some time of the year and conduct research.

Ratio and Proportion

What is a ratio?

Ratio is a relationship between two numerical values. It shows how many times one value contains another value.

Examples of ratio

When we make mango crush, we are told to add one part crush to four parts water. Which means if I take one cup of crush, I need to add four cups of water. This is a relation that can be written as 1:4.

How to solve ratios?

Sam wants to make tea with the ratio of milk to water to be 2 : 3. If he needs to make 5 cups of tea, how much milk and water will Sam need?

Answer – Sam needs a ratio of 2 : 3, thus the total parts of his mixture are 2 + 3 = 5. Since he is making 5 cups of tea, 1 cup can be said to be equal to one part.

Milk has to be 2 parts out of 5 so Sam will need 2 cups of milk.
Water has to be 3 parts out of 5 so Sam will need 3 cups of water.

What is a proportion?

Proportion is used to describe how much of a certain component is there in something. Like our mango crush will always be one part of crush and four parts of water. Thus there is a total of 5 parts in our crush. So mango crush will always be one part out of five and thus ⅕.

Types of proportion

1. Direct proportion

In the case of our crush, if we take one cup crush, we need to add four cups water. If we take two cups of crush, we will have to add eight cups of water. Thus if the quantity of one proportion increases, the quantity of the other also increases. This is called Direct Proportion.

2. Indirect proportion

If the quantity of one value increases, the other goes down, and vice-versa. This relationship is called Indirect Proportion.

Examples of proportion

In some cases like in a race, the relation between speed and time taken to cover a specific distance is proportional but not directly.

If we are travelling at 20 km per hour, we will cover 20 kilometer in one hour.
If we are travelling at 40 km per hour, we will cover 20 kilometer in half an hour.

As you can see, if the quantity of one value increases, the other goes down.

Proportion formula

If a:b::c:d then a/b=c/d

How to solve a proportion

If a car travels 30 km in one hour, then how far will it travel in two hours?
Answer – Let us assume the car travels Z km in two hours.

By the formula of proportion-
30km : 1 hour = Z km : 2 hours

So 30/1= Z/2

Z= 30/1 x 2

Z = 60

Thus the car will travel 60 km in two hours.

Ratio worksheet with answers

1) Rachel needs to make lemonade from the lemonade syrup, she has to add syrup to water in the ratio of 1:6. How will Rachel make 14 cups of lemonade?

A) 12 cups water to 2 cups syrup
B) 6 cups water to one cup syrup
C) 4 cups water to 10 cups syrup
D) 2 cups water to 12 cups syrup

Answer: A

2) Emma is told to make mix fruit juice with a 1:1 ratio of orange juice to pineapple juice. To make 1 liter of juice how much orange juice will she need

A) 1.5 liter of orange juice
B) 1 liter of orange juice
C) 0.5 liter of orange juice
D) 0.3 liter of orange juice

Answer: C

Proportion worksheet with answers

1) If a car goes 20 km in two hours, how far will it go in one hour?

A) 40 km
B) 30 km
C) 10 km
D) 5 km

Answer: C

2) Casper walks 5 km in one hour. The shop is half an hour away, how far is the shop in terms of km?

A) 2.5 km
B) 3 km
C) 1 km
D) 4 km

Answer: B

The Battle of Plassey

Why is the Battle of Plassey important to Indian colonial history?

The Battle of Plassey is considered a crucial event in Indian colonial history. The British East India Company was able to gain control after winning the battle against the Nawab of Bengal, Siraj – ud – Daulah. After this battle, the East India Company consolidated British presence in Bengal and then India, leading to nearly 200 years of British rule in India.

What led to the Battle of Plassey?

The British trading company, East India Company, had been given a royal charter by Queen Elizabeth on 31st December, 1600 to pursue trade in the East Indies. It included the right to form an army.

Although territorial conquest was not a priority in the first century of the company’s operations, it soon became the agenda to maintain trade in South Asia. The company faced competition from the rival companies, French East India Company and the Dutch and Portuguese counterparts. The different companies formed allies with various rulers to extend support against rebels and usurpers in exchange for trading support.

After the decline of the Mughal Empire and several independent rulers during the three Carnatic Wars, the British gained a stronger foothold in India.

The British forces became dominant, as a result of which, the British East India Company was able to extend and establish its powers and became the British Raj.

How did the Battle of Plassey take place?

  • In 1755, Siraj – ud – Daulah, became the Nawab of Bengal and allied with the French East India company. He then proceeded to overrun British trading posts, including the ones in Calcutta, because he felt the British were overriding his power and position as Nawab. He captured Fort William in Calcutta, in the Bengal Presidency, in 1756.
  • Lieutenant Colonel Robert Clive was sent from Madras to retake Calcutta. One of Siraj – ud – Daulah’s discontented followers, Mir Jafar was instrumental in betraying him to the British.
  • The Battle started with the French troops supporting the Nawab. Mir Jafar failed to join in the fighting, despite pleas from the Nawab. The battle was heading for a stalement, when it started to rain. The British troops were prepared with tarpaulins to keep the gun powder dry, but the Bengali troops were unprepared.
  • Unaware, the Nawab underestimated the British and open charged. The British open fired at the charging Bengali cavalry. They lost their commander, panicked and started moving back, exposing their artillery.
  • The British captured the Nawab’s artillery. The Nawab fled the battlefield and Mir Jafar was installed as a puppet ruler by the British.
  • This was the beginning of the rise of the British Raj in India.

Aung San Suu Kyi Biography

Early life

Aung San Suu Kyi was born on June 19, 1945, was born to a Burmese General Aung San and his wife, Daw Khin Kyi. Her father had helped Burma in gaining independence from the United Kingdom in the year 1947. He was assassinated the same year. After her father’s demise, her mother looked after her solely.

Education and career

Suu Kyi received her early education in Rangoon, Burma (now known as Myanmar) until she was 15 years old. In 1960, she came to India with her mother when she came as the Burmese ambassador to India and Nepal. Suu Kyi studied politics at the Delhi University. She earned a bachelor’s degree in philosophy, politics and economics from St. Hugh’s College, Oxford University. Thereafter, she started working for the UN. In 1972, she got married to Dr. Michael Aris, a professor of Tibetan culture who lived in Bhutan, and had two children.

Entry into active politics

In 1988, she returned to Burma to take care of her sick mother. She noticed that the Burmese people desired to break free from the military rule and wanted democracy. She decided to help her countrymen in establishing the democratic order in the country. Towards this purpose, she formed the National League for Democracy on 27 September, 1988.

Arrest and elections

Aung San Suu Kyi was arrested in 1989 and put behind bars in 1990. This happened just after an election in which her party, then National League for Democracy, had won by a considerable majority. The military, however, still did not allow her to take charge of her country. Between 1990 to 2010, she was either kept in the prison or in the house arrest. During the periods of confinement, Kyi engaged herself in studying languages such as French and Japanese, meditation and exercising.

Myanmar’s first free general election

In November 2010, Myanmar held its first general elections in 20 years. The army-backed Union Solidarity and Development Party won by a large majority. The new government released Suu Kyi from house arrest. In April 2012, Suu Kyi stood in the elections and won a seat for herself in the parliament. Moving on, she led her party to a majority win in Myanmar’s first openly contested election in November 2015. Today, she is the state counsellor of Myanmar and a close confidant of the President, Htin Kyaw.

Awards and accomplishments

Aung San Suu Kyi has played a vital role in establishing democracy in Myanmar. Her outstanding contribution is that Myanmar politics is recognized by the world.
Suu Kyi received the Thorolf Rafto Memorial Prize and the Sakharov Prize for Freedom of Thought in 1990.

Nobel Peace Prize

In 1991, she received the prestigious Nobel Peace Prize, and in 1992, she was awarded the Jawaharlal Nehru Award for International Understanding by India. The US House of Representatives awarded her the Congressional Gold Medal in 2007. At that time, she was still in the prison. She was made an honorary citizen of Canada. In 2014, she was listed as the 61st most powerful woman in the world by Forbes.

4 Interesting facts about Aung San Suu Kyi

  1. Aung San Suu Kyi’s name is made up from the names of three of her family members- ‘Kyi’ from her mother, ‘Aung San’ from her father and ‘Suu’ from her grandmother’s name.
  2. Aung San Suu Kyi has been in the prison or under house arrest for more than 15 years
  3. She is deeply influenced by the ideologies of Mahatma Gandhi and Buddhism.
  4. Aung San Suu Kyi has also authored a number of books. Her most popular works are – Freedom from Fear, The Voice Of Hope, Let’s Visit Burma and Letters from Burma

Structure of An Atom

What is an atom?

Everything in our universe is made of matter and matter is made of atoms. An atom maybe described as the smallest particle that matter is made with and has the properties of a chemical element. An atom is minute in size and typical sizes are in picometers, a ten billionth of a meter.

What are atoms made of?

An atom is made of three parts – protons, neutrons and electrons.

Each of these parts has an associated charge. The protons carry a positive charge, electrons have a negative charge and neutron possess no charge. Protons and neutrons make up the nucleus of the atom and electrons orbit the nucleus at different energy levels.

What is atomic number?

Atomic number of an atom is defined by the number of protons in the nucleus of an atom.

What is atomic mass?

Atomic mass of an atom is equivalent to the number of protons and neutrons in the atom.

Parts of an atom

What is a proton?

A proton is a positively charged particle found within the atom’s nucleus. Rutherford discovered them in his experiments with cathode ray tubes.

The number of protons in an atom define what the element is. This is what is referred to as the atomic number of that element. The number of protons also determine the chemical behaviour of that element.

What is a neutron?

A neutron is the neutral part of the atom’s nucleus, with no electric charge, and a mass slightly larger than that of a proton. It was discovered by the English physicist, James Chadwick.
Neutrons and protons combined make up the mass of the atom. We can find the number of neutrons if we know the atomic mass and the atomic number of an element, using this simple equation.

Atomic Mass – Atomic Number = Number of Neutrons

Atoms of the same element may have different number of neutrons. Adding neutrons changes the radioactivity of the element, without changing the charge of the atom. This is important in nuclear physics.

What is an electron?

An electron is a negatively charged part of the atom found outside the nucleus in orbits and are attached to the protons in the atom with electromagnetic force. Closer the electron to the nucleus, the stronger the electromagnetic force between them.

Electrons can escape from their orbit in response to an external energy being applied. It can also change its state to a higher energy level by absorbing a photon with sufficient energy to boost it to a new quantum state. It can also drop down to lower energy state emitting the excessive energy as a photon.

Atoms are neutral if the number of protons and electrons are equal. Atoms that have an excess or deficit of electrons are called ions. Electrons have no internal structure, though protons and neutrons on the other hand are made of quarks.

Thomson’s model of an atom

The Thomson Model of an atom was proposed by JJ Thomson, in 1897. He discovered electrons while experimenting with cathode ray tube. The cathode ray tube was negatively charged. He also studied positively charged particles in neon gas. Although his theory explained somethings about atoms and electrons, it failed to provide sufficient information about the positively charged particles and the nucleus of the atom.

Rutherford model of an atom

After the model of an atom, by Thomson, was unable to explain the positively charged particles in an atom, Ernest Rutherford proved the presence of positively charged particles in the nucleus of an atom through the gold foil experiment. This theory proved that the nucleus of an atom contains positively charged particles.

Bohr’s model of an atom

Bohr’s model of an atom was proposed by Neil Bohr in 1915. He specified that electrons move in fixed orbits/shells, which have fixed energy levels.

What is valency?

Valency is a measure of the reactivity of an atom. It is defined by the capacity of the atom to lose or gain valence electrons in the valence shell.
Every atom wants to have 8 electrons in the valence shell and this is known as the octet rule.

What are isotopes?

Isotopes are atoms with the same number of protons but that have a different number of neutrons. Since the atomic number is equal to the number of protons and neutrons, isotopes have the same atomic number, but different mass numbers.

Carbon 14, used in carbon dating to find out the age of really old archeological and biological remains, is an isotope of carbon.
Tritium, an isotope of hydrogen, is used to make glow in the dark faces on clocks and wrist watches.

What are isobars?

Isobars are defined as atoms of different elements that have the same atomic mass number, but different atomic number.
Carbon 14 and Nitrogen have the same mass number, which is 14, hence they are isobars.

How to write an essay?

What is an essay?

Essays are brief, non – fiction compositions that describe, clarify, argue or analyse a subject. An essay is composed of an introduction, body and conclusion. An essay will teach you to communicate with specific readers as it is a shorter form of communication with a clear beginning, middle and end.

Basics of essay writing

The purpose of your essay is determined by your goal. Some essays will be to either inform, to persuade, to explain or to entertain.

To write a good essay, it is very important to first understand the purpose and the title. A good title will make sure you :

  1. Understand the precise task set by the title.
  2. Identify the right research or reference material.
  3. Divide the content of your essay before you begin to write it, which is introduction, body and conclusion and are able to have a clear thesis statement.
  4. Are able to construct informative content in the body text and have an effective conclusion for it.

Importance of research in an essay

A well researched essay is interesting to read as well as makes sure, the reader can understand what you are trying to say, without too much trouble. Research makes sure you have understood and can prove what you are communicating.

How to organize your essay?

A well written essay makes interesting reading, irrespective of the subject. Some of these points help you to write it better.

  1. After you finish, read it again and see if it has covered the points you want to communicate.
  2. Is the language kept clear, without the use of words you do not understand?
  3. Made sure your body text essay is divided into paragraphs to separate or breakdown the points or topic you are discussing.
  4. Make sure your essay has enough examples if it is explaining something.

So, how to write a good essay?

Here is a simple way to write a good essay.

Step 1. Title of the Essay

  • Decide the title of your essay.

Step 2. Introduction of the Essay

  • When writing the introduction, remember, the introduction should have two important parts. A sentence outlining what your essay will be about and a sentence outlining what your point of view on the subject of your essay is. It should be interesting enough to attract the attention of the reader.

Step 3. Text Body or Content Text Body of the Essay

  • Writing the body of the essay requires that you organise the subject of your essay into parts.
  • Divide each point into paragraphs. Illustrate and support the points with research, diagrams, illustrations and comparisons to explain it well.

Step 4. Conclusion or Ending to the Essay

  • Writing the conclusion will help you put together the points you have discussed in the essay into a simple and logical way. Make sure it is brief and presents your point of view well.

Quick writing tips

  1. Practice writing simple sentences every day.
  2. Learn a new word every day, with its meaning.
  3. Practice punctuations and grammar.

Difference between elements and compounds

What is an element?

An element maybe defined as any substance that :

  • Contains only one kind of atom.
  • It cannot be broken down into a simpler form due to either a chemical or physical means (Copper or Sulphur)
  • Can exist as either atoms or molecules (Oxygen or Nitrogen)
  • Elements are arranged in the periodic table and are assigned a unique symbol based on their name.
  • Elements are divided into three categories that have characteristic properties: metals, non metals and semi – metals.

What is a compound?

A compound consists of two or more elements bonded together through a chemical reaction. A compound can be separated into its constituting elements only through a chemical reaction.

Types of compounds

These are divided into ionic compounds and covalent compounds.

1. Ionic compounds

They are made of electrically charged atoms or molecules, as a result of gaining or losing electrons. Ions of opposite charges form ionic compounds and usually a metal reacting with a non – metal.

  • NaCl
  • CO
  • KI

2. Covalent compounds

Also known as molecular compounds, these are formed when two non metals react with each other. The elements form a compound by sharing electrons, resulting in an electrically neutral molecule.

  1. C6H6
  2. CH3COOH
  3. C2H5OH

How do we write a compound formula?

The names of compounds are their chemical formula. These are generally descriptions of their composition and the valency of the elements. An element can form a compound with another element, only if the outer shell has electrons to either give or space to take electrons to form the electron octet.

The naming is done by :

  • Writing the symbol for the composition of the compound with the cation first and the anion after.
  • Determine the valance or charge of each element and place it in brackets above the symbol.
  • Balance the total positive and total negative charge on the cation and anion. The total of cation and anion must be zero.

Most compounds are named by the elements’ position on the periodic table.

Etruscan Shrew Facts and Information

What is an Etruscan Shrew?

The Etruscan shrew is the smallest mammal known by its body mass. It lives in the forests of Southern Asia and Southern Europe. It is also known as the etruscan pygmy shrew or the white – toothed pygmy shrew. It’s biological name is Suncus etruscus.

The smallest living mammal

The smallest mammal known by its size on the other hand, is the bumble bee bat, inhabitant of Thailand and Myanmar.

What does the Etruscan Shrew look like?

Being the smallest mammal, its average body weight is about 1.8 grams(0.063 oz) and it measures about 4 cms(1.6 inches), excluding the tail. The head is relatively large with a long, mobile proboscis and its hind legs are comparatively small.

Animal with the fastest heart rate

Because of their small size, the Etruscan shrew has a very high metabolic rate and the heart beats at very high rates per second. The heart is relatively large and is 1.2% of their body mass and beats at 1511 beats per minute. The shrews eat almost two times their weight in a day and eat every two hours or they will starve. They do not hibernate and because of this high metabolic rate, the shrews do not sleep and seldom rest for more than a few seconds.

What is a typical Etruscan Shrew’s life like?

  • The Etruscan shrew are insectivores. Although they prey on insects, they are themselves pryed on by birds like buzzards, owls cats and other small predators.
  • The largest threat to shrews however comes from humans to their nesting grounds and living habitats, as a result of farming and agricultural practices.

3 Amazing facts about the Etruscan Shrew

  1. Etruscan shrews generally live alone and can be very territorial, except during mating seasons.
  2. Etruscan shrews are known as short – range, high speed hunters. In darkness, they can detect, overwhelm, and kill their fast moving insect prey, which can be almost their size.
  3. They have a life span of one and half years.

What is Flora and Fauna?

What is the difference between flora and fauna?

The words flora and fauna are used by the scientists to describe the plant and animal life in a region or area.

What is flora?

The word ‘flora’ comes from the Latin word ‘Flora’ who was believed to be the princess of flowers. Flora is a collective noun used to describe all the plants, trees, fungi and bacteria that may be present in a particular region.

What is fauna?

Fauna comes from two Greek words ‘Faunus’, the name of a Roman god and ‘Fauna’, the name of a mythical Roman goddess. It is a collective noun that is used to describe all the animal life in a particular region.

Importance of flora and fauna

The flora and fauna present in the different corners of the Earth have made life possible on this planet. Both plants, as well as animals, help in maintaining the delicate ecological balance on Earth. The flora produces the oxygen which is taken in by the fauna. In turn, the fauna releases the carbon dioxide that the flora needs to live. So, one cannot live without the other, and we, humans, cannot live without either. The existence of one species depends upon the existence of the other. For example – Pandas eat only bamboo shoots. The destruction of the bamboo forests in China has driven Pandas on the brink of extinction due to food shortage and habitat loss.

Why does India have a rich heritage of flora and fauna?

India is a country with different types of soils, climatic conditions and geographical features which is why it supports a broad spectrum of species of flora and fauna.

What is so special about the flora and fauna of Australia?

Australia’s ecosystem is a unique one because of its unique location. As a result, many species of animals and plants that are found here are not found anywhere else in the world, such as the platypus, kangaroo, echidna, and koala. The small continent of Australia has more than 516 national parks to protect its unique plants and animals. There are several types of rainforests in Australia such as the tropical rain forests, subtropical rainforests and broadleaf rain forests.

2 Interesting facts about flora and fauna

  1. Botanists, or plant scientists, mainly study flora, while zoologists study fauna. Ecologists are the scientists who study both flora and fauna together.
  2. India is one of the 12 mega biodiversity countries of the world and has about 47,000 plant species and 89,000 species of animals.

Red Cross Facts and Information

What is the Red Cross?

The International Red Cross and Red Crescent Movement is the world’s largest humanitarian network that helps needy people during the times of war and natural disasters. It comprises of:

  • The International Committee of the Red Cross
  • The International Federation of Red Cross and Red Crescent Societies
  • National Red Cross and Red Crescent Societies with 190 registered societies

How was the Red Cross formed?

It was a horrific battle that gave birth to the idea for the Red Cross. In 1859, a Swiss entrepreneur Jean Henri Dunant went to meet the French Emperor Napoleon III, seeking his help for a business venture. Dunant did not get a chance to meet the French emperor. However, he happened to witness a gruesome battle – the Battle of Solferino, in which some 40,000 troops were killed or wounded in a single day. Realizing that neither of the warring armies had the medical corps, Dunant arranged for a group of volunteers to bring medical aid and food to the wounded.

International Committee for Relief to the Wounded

In 1863, Dunant, with four other men in Geneva, established an organization called ‘International Committee for Relief to the Wounded’ which was later renamed as the Red Cross. After a year in 1864, under the leadership of Red Cross, 16 countries held a conference at Geneva and signed the Geneva Convention which is now a code of conduct for war for protecting wounded soldiers, Red Cross volunteers, prisoners of wars and civilian population. The same meeting adopted the white flag with a red cross which is the reverse of the Swiss flag, having a white cross in the background.

What does the Red Cross do?

The mission of the Red Cross is to provide humanitarian service for victims of war and natural disasters. During wartime, it provides its services to the wounded soldiers and prisoners of war. It also provides medical aid to the victims of natural disasters such as tsunami, drought, earthquake and flood. During peacetime, it organises educational awareness campaigns to improve the health of the general public. Blood bank management, ambulance service, mobile health camps, health training, tree plantation and sanitation are some of the main activities of the Red Cross volunteers.

8 Interesting facts about the Red Cross

  1. World Red Cross Day is celebrated on May 8 every year, to commemorate the birth anniversary of the movement’s founder, Jean Henri Dunant.
  2. For coming up with the idea of Red Cross and his contribution towards its activities, Jean Henri Dunant was awarded the first Nobel Prize for Peace in 1901.
  3. The Red Cross network had raised more than $3 billion for relief for the 2004 Indian Ocean tsunami victims.
  4. In the year 2008, the IFRC responded to 623 disasters worldwide.
  5. The network has more than 97 million staff, volunteers, and supporters.
  6. Red Cross known as Red Crescent in the Muslim countries and Red Star in Israel.
  7. The Red Cross organisation has won three Nobel Peace Prizes-in 1917, 1944 and 1963.
  8. The writer Hemingway was an ambulance driver in World War 1.

Great Blue Hole of Belize Facts

What is the Great Blue Hole of Belize?

The Great Blue Hole is a huge submarine sinkhole. It is located near the center of the Lighthouse Reef, a small island 100 kilometres from the Belize City.

How deep is the Great Blue Hole of belize?

The hole is circular in shape, and is over 300 meters across and 125 meters deep. It is the world’s largest natural formation of its kind and is an integral part of the larger Barrier Reef Reserve System, which is a World Heritage Site of the United Nations Educational, Scientific and Cultural Organization (UNESCO).

How was the Great Blue Hole Belize formed?

The Great Blue Hole formed in stages, starting about 153,000 years ago as a sinkhole. The sinkhole originally formed as a limestone cave during the last glacial period. This was a time when the sea levels were much lower. As the ocean started to rise, the cave got flooded and finally collapsed, resulting in a ‘vertical cave’ in the ocean. This research was done by French Naval Officer and pioneer marine biologist, Jacques Cousteau, in the year 1971.

Who named the Great Blue Hole Belize?

The name ‘Great Blue Hole’ was given to this spectacular natural geographic feature by the British diver and author Ned Middleton, in his book Ten Years Underwater.

What type of animals and plants are found in the Great Blue Hole of Belize?

There are over 500 rare forms of animal and plant life found in the Great Blue Hole of Belize. Here, you would be able to meet several unique species of fish, including Midnight Parrotfish, Caribbean Reef Shark, and other rare fishes.

What kind of sharks are in the Blue Hole Belize?

Sharks such as the Bull Shark and Hammerheads, have also been reported here.

3 Interesting facts about Great Blue Hole of Belize

  1. Each year, more than 200,000 people come to visit the Great Blue Hole of Belize from all over the world.
  2. The Blue Hole Monument is one of the seven wonders of the Belize’s World Heritage site.
  3. The Discovery Channel placed the Great Blue Hole Belize at number one on its list of ‘The 10 Most Amazing Places on Earth’.

How is the American President elected?

Requirements to become President of the United States

The American constitution states that the presidential candidate should be –

  • 35 years of age
  • A United States of America resident for 14 years
  • A ‘natural born citizen’ of the United States of America

Voting rights in the United States

The government of the United States of America, gives the right to every person over the age of 18 to vote. Voting is considered not just a right, but also a privilege and a big responsibility.

Political parties in the United States

The two main political parties in the United States are the Republican and Democratic Parties. Members of both the parties have different views on different issues related to the country. It is a good thing as different sides of important issues get discussed and voted on.

How do candidates take part in the elections?

A presidential candidate first makes an official announcement that he or she is running for president. Then, he/she files papers with the federal elections commission, which controls the election process. Candidates usually make these announcements atleast a year before the presidential election. This is done to ensure enough time for the election campaigns.

Canvassing of votes for President

Once the candidates file their names for the election, they make an endeavour to remain in the public eye. This process is known as election campaigns or canvassing. The candidates try to convince voters to vote for them. They give elaborate public speeches and tell people about their agendas and what reforms will they introduce upon getting elected. They also run advertisements on TV, distribute buttons, and have debates to let the citizens know why they are the best candidate for the job.

How is the President elected?

The American President is elected by the Electoral College. The American President is elected according to the process of the Electoral College. The citizens of the US do not directly elect the President. People actually vote for an elector from their state, and these electors then vote for President.

Each state has a specific number of delegates in the Electoral College based on the population of the state. Once all the votes are in, the candidate who wins the majority of electoral votes, becomes the President. There are 538 total electors in the United States and a total of 270 electoral votes is required to win the presidential election.

How are votes counted?

After the polls close on the day of the election, the process of counting the votes begins. Each state has a different method to collect and tabulate ballots. Some are electronic, while others are paper-based. The votes are counted in a joint session of Congress.

What are primary elections or caucuses?

When the elections are on, the people in the United States gather to show their support for different candidates. Such gatherings are known as the primary elections or caucuses. During the primary elections, the voters get ballots having a list of the names of the candidates running for president. They go to a polling booth and vote for their favourite candidate.

What is a swing state?

In American politics, the term swing state implies to any state that could be easily won by either the Democratic or Republican presidential candidate. These states are usually targeted by both the major fighting political parties.

5 Interesting facts about the United States Presidential Elections

  1. Earlier only white men over the age of 21 were allowed to vote in the United States of America, but it was changed later on and now everyone over 18 years of age can vote regardless of race or gender.
  2. The process of voting is extremely important for the democratic countries as by way of voting people get to have their say in the government.
  3. The first automatic voting machine was invented in 1898.
  4. Other political parties in the USA are Reform, Green, Natural Law, and Libertarian.
  5. The major swing states in the United States are Florida, Ohio and Pennsylvania.

What is a region?

Definition of Region

A region is a specific area that has common features. A region may have common natural or artificial features. A region can be based on language, government, religion, type of flora and fauna or climate. Regions are the basic units of geography.

Why do Geographers use regions to study the Earth?

It is impossible to study our planet Earth as one unit or region as there is so much of information to be incorporated. Regions are one way to arrange and simplify this huge amount of information.

What is Regional Geography?

Regional geography is the branch of Geography that deals with the division and study of the Earth into different regions. The famous geographer, Paul Vidal de la Blanche is regarded as the father of Regional Geography.

Types of regions

1. Physical or Land region

Physical or land region is an area with geographic boundaries. For example- in the United States, there is a major physical region known as the Great Plains. This specific region has a lot of grass, is flat, and is home to animals like bison and antelope. Similarly, the Amazon River region in South America is characterized by warm temperatures, heavy rainfall, and similar diversity of plant and animal species.

2. Cultural region

People in one cultural region have same beliefs, speak the same language, eat the same food and have same cultural practices.

3. Political region

Political regions are decided on the basis of the political party ruling over that particular area. States are an example of the political regions.

What are the different regions of the world?

According to the United Nations, the world is composed of 10 major geographic regions: Africa, Asia, North America, South America, Central America, Eastern Europe, the European Union, the Middle East, the Caribbean and Oceania.

Different regions of the United States of America

The United States is divided into five major regions –

  1. Northeast region that includes Maine, Massachusetts, Rhode Island, Connecticut, New Hampshire, Vermont, New York, Pennsylvania, New Jersey, Delaware, Maryland Climate. The Northeast region has a humid continental climate with cool summers. The temperatures in these areas remain mostly below freezing. Major geographical features include the Appalachian Mountains, Atlantic Ocean, Great Lakes.
  2. Southeast region that includes West Virginia, Virginia, Kentucky, Tennessee, North Carolina, South Carolina, Georgia, Alabama, Mississippi, Arkansas, Louisiana, Florida. The climate in this region is humid subtropical with hot summers. This region is hurricane prone. Major geographical features include the Appalachian Mountains, Atlantic Ocean, Gulf of Mexico, and Mississippi River.
  3. Midwest region including Ohio, Indiana, Michigan, Illinois, Missouri, Wisconsin, Minnesota, Iowa, Kansas, Nebraska, South Dakota, North Dakota. The climate is humid continental throughout most of the region. Major geographical features comprise of Great Lakes, Great Plains, and Mississippi River.
  4. Southwest region including Texas, Oklahoma, New Mexico, Arizona. The climate is Semiarid Steppe in the western area and humid towards the east. Major geographical features are Rocky Mountains, Colorado River, Grand Canyon, and the Gulf of Mexico.
  5. West region including Colorado, Wyoming, Montana, Idaho, Washington, Oregon, Utah, Nevada, California, Alaska. This region has a range of climates including semiarid to alpine and Mediterranean to Desert as well. Major geographical features include Rocky Mountains, Sierra Nevada Mountains, Mohave Desert and the Pacific Ocean.

2 Interesting facts about region

  1. Due to plate tectonics, or the movement of the Earth’s crust, geographic regions are constantly being created and destroyed over time.
  2. Regional geography specifically started getting popularity in the United States and Europe during the period between World Wars I and II.

Napoleon Bonaparte Biography

Who was Napoleon?

Napoleon was a great military leader and the emperor of France. He was born on August 15, 1769 at Ajaccio, Corsica. His father was Carlo Buonaparte was a lawyer at the court of the French King. Since Napoleon came from a wealthy family, he was able to go to the best of the schools and get a good education. He went to a military academy in France and became an officer in the army. After his father’s demise, Napoleon returned to Corsica to help in handling the family’s affairs. While in Corsica, Napoleon joined hands with a local revolutionary – Pasquale Paoli and helped him in fighting against the French. Soon after, he changed sides and returned to France. Napoleon married his first wife, Josephine, in 1796 but divorced her in 1810 to marry Marie-Louise of Austria.

How did Napoleon become the ruler of France?

At age 26, he began his first military campaign against the Austrians. With his amazing leadership and warfare skills, he won over the Italian Peninsula and became a national hero. In 1798, he led a military expedition to Egypt which was extremely successful. In 1799, the ruling government in France called the Directory, started to lose its control over the country. Together with his supporters, in 1804, Napoleon formed a new government called the Consulate and gave himself the title of First Consul.

How was Napoleon as a ruler?

As the Consul of France, Napoleon established a number of government reforms. One of these reforms was the famous Napoleonic Code which stated that government positions would not be appointed based on a person’s birth or religion, but on their qualifications and ability. Before the French Revolution and the implementation of the Napoleonic Code, all high positions were bagged by those from the royal families or to those whom the kings favoured. Napoleon gave a boost to the French economy by building new roads and promoting business. He re-established Christianity as the official state religion, but at the same time allowed for freedom of religion to his citizens. Napoleon also set up non-religious schools, so children could get education. Napoleon’s power and control continued to grow with his reforms. In 1804, he crowned himself the Emperor of France.

Napoleon’s military timeline

Napoleon defeated the Austrian and Russian armies at the Battle of Austerlitz in 1805.

  • 1811 – France controlled most of Europe.
  • 1812 – Napoleon decided to invade Russia.
  • 1813 – Most of Europe had turned against France. Prussia and Spain declare war on France.
  • 1814 – Napoleon was forced into exile on the island of Elba.
  • 1815 – Napoleon escaped from Elba and gathered his army and took control of Paris for a period also known as the Hundred Days.
  • 1815 – In June, the armies of English and Prussia, led by Wellington and Blucher defeated Napoleon at Waterloo. This time Napoleon was once again forced into exile on the island of Saint Helena.

When did Napoleon Bonaparte died?

  • Napoleon died on May 5, 1821

5 Interesting facts about Napoleon Bonaparte

  1. Napoleon’s nickname was Little Corporal.
  2. Napoleon is famous for being fairly short, probably 5 feet 6 inches tall.
  3. His birth name was Napoleone di Buonaparte.
  4. He wrote a romance novel called Clisson et Eugenie.
  5. In 1804, he was crowned the Emperor France. At the coronation, he did not allow the Pope to place the crown on his head, but instead crowned himself.

5 Famous Quotes by Napoleon Bonaparte

  1. A soldier will fight long and hard for a bit of coloured ribbon
  2. If you want a thing done well, do it yourself
  3. Death is nothing, but to live defeated and inglorious is to die daily
  4. Never interrupt your enemy when he is making a mistake
  5. A leader is a dealer in hope.

Nutrition in Plants

How do plants get their food?

Plants can manufacture their own food, but animals including human beings cannot and rely on plants for their food.

All living organisms need food for the following :

  • Cell regeneration
  • Energy for cellular functions
  • Immunity against diseases
  • Plants make their foods using either the Autotrophic nutrition and Heterotrophic nutrition.

What is Autotrophic nutrition?

When green plants make their food using simple substances like sun light, water, carbon dioxide and minerals, the process is known as Autotrophic nutrition. This type of nutrition is also known as Holophytic nutrition. These types of plants are known as autotrophs. The words, ‘auto’ means self and ‘trophos’ means nourishment. Autotrophs are the producers in a food chain.

What is Heterotrophic nutrition?

A heterotroph is an organism that cannot manufacture its own food by carbon fixation and therefore derives its intake of nutrition from other sources of organic carbon, mainly plant or animal matter. In a food chain, heterotrophs are secondary and tertiary consumers. This is also known as Holozoic nutrition, as the food is ingested and goes through a digestive process.

What are the types of Heterotrophs?

The types of heterotroph are :

  1. The animals that are directly dependent on plants are called herbivores. For example – Deer, Cow, Goat and Rabbit.
  2. The animals that eat the flesh of other animals are called carnivores. For example – Lion, Tiger, Wolf and Snake.
  3. The animals that feed on both plants and animals are called omnivores. For example – Man, Bear and Crow.
  4. The animals that feed on the flesh of dead animals are called scavengers. For example – Kites and Vultures.

Photosynthesis in plants

Plants manufacture their food in their leaves. The leaves, are therefore, also known as the kitchen or food factories of the plants. Photosynthesis is the combination of two words – Photo and synthesis. ‘Photo’ means light and ‘synthesis’ means to make.

The reaction that takes place in the process of photosynthesis can be written as :

6CO2 + 6H2O ——> C6H12O6 + 6O2

Plants require the following things to carry out the process of photosynthesis –

  • Sunlight
  • Water
  • Carbon – dioxide
  • A green pigment known as the Chlorophyll

Leaves have numerous small pores like structures on their lower surface. These pores are surrounded by ‘guard cells’. These pores are called stomata. The stomata are guarded by two bean-shaped cells known as the guard cells. Leaves absorb carbon dioxide from air through stomata. Water is transported to the leaves through the Xylem tissue.

What is chlorophyll?

Chlorophyll is a green pigment found in the leaves. It gives the leaves their characteristic green colour. The job of chlorophyll is to absorb sunlight, carbon dioxide and water and convert them into carbohydrate and oxygen.

Importance of photosynthesis

The process of photosynthesis is very useful for our environment. It maintains a balance between the concentration of oxygen and carbon dioxide in the atmosphere. Plants release oxygen that is essential for our survival and that is why it is said that we must plant more trees.

What are the modes of nutrition in non-green plants?

There are some plants that lack chlorophyll. Such plants are also known as non-green plants and they cannot synthesise their own food. They depend on other organisms for food. Let us learn about some of the important non – green plants.

1. Parasitic plants

A parasite is an organism which lives on or inside the body of another organism and takes shelter and food from that organism. An organism which provides shelter and nutrition to another organism is called a host. The host in this case is always at loss.

Plants that get their food from other plants by living on them are called parasitic plants. For example – Cuscuta or Amarbel and Mistletoe. Cuscuta is a vine-like plant with a yellow coloured stem. It coils around big trees, like the Banyan tree and gets nutrition from it. In this case, Banyan tree is the host and Cuscuta is the parasite.

2. Insectivorous plants

The plants that eat insects are called insectivorous plants. They trap and digest the insects. For example – Pitcher plant is an insectivorous plant in which the leaves are modified into pitcher – shaped structures. The insects get attracted to the bright colour and sweet-smelling nectar of the pitcher plant. When an unsuspecting insect sits on the pitcher of the plant to take a sip of the nectar, the lid of the pitcher closes and the insect gets trapped inside. The insect is then digested by the enzymes released by the cells of the plants. Venus flytrap, Utricularia and Drosera are some other examples of insectivorous plants which trap and kill small flies and spiders in different ways.

3. Saprotrophs

The non-green plants that feed on the dead and decaying matter like animal wastes are called Saprotrophs or Saprophytes. For example – Fungi like Agaricus, Yeast and Bacteria.

4. Symbiotic plants

Symbiosis is the combination of two Greek words ‘Sym’ means ‘with’ and ‘biosis’ means ‘living’. In other words, symbiosis means ‘living together’. Symbiosis is the type of nutrition in which two different kinds of living organisms depend on each other for survival. They share shelter and nutrients. For example – Lichen. Lichen is a composite organism made up of fungus and alga. Fungus is a saproptroph and alga is an autotroph. The fungus provides water and minerals to the alga and in return the alga supplies food prepared by photosynthesis to the fungus.

3 Interesting facts about plants

  1. Insectivorous plants generally grow in swamps or marshy areas because the soil in such areas is deficient in nitrogen. To fulfill their nitrogen need, the plants trap and kill the insects.
  2. There are roughly 600 species of carnivorous plants which have different strategies to capture their prey.
  3. Charles Darwin was very fond of the carnivorous plant – Sundews, or Drosera.

What is Heron’s Formula?

Heron’s formula, sometimes known as Hero’s formula is named after Hero of Alexandria, a mathematician, and engineer in 10 AD.

Definition for Heron’s formula

Heron’s formula gives the area of a triangle by requiring no arbitrary choice of side as base or vertex as origin, contrary to other formulas that calculate the area of a triangle. The area can be calculated using all the three sides, especially in scalene triangle, where none of the sides are equal. Most formulas use the height of a triangle to calculate the area.

What are the steps for Heron’s formula?

According to this formula,

Area of the triangle –

A = \sqrt{s(s-a)(s-b)(s-c)},

where the semi – perimeter of the triangle,


a, b, c are the lengths of the sides of the triangle.

Heron’s Formula Worksheet

1. Calculate the semiperimeter of a triangle, s, where a = 23, b = 40, c = 35.

a. 35
b. 48
c. 25
d. 49
Right Answer- d. 49

2. Calculate the area of a triangle using Heron’s formula, if the three sides of the triangle are, a = 5, b = 9, c = 6

a. 12.34
b. 10.6
c. 14.14
d. 13.26
Right Answer- 14.14

3. Calculate the side of a triangle b, if side a = 12 and side c = 6 and the semi – perimeter equals 13.
a. 9
b. 8
c. 6
d. 7
Right Answer- b. 8

3 Interesting facts about Heron’s Formula

  1. Heron’s formula has been known to mathematicians for nearly 2000 years.
  2. Proof of this formula can be found in Hero of Alexandria’s book “Metrica”.
  3. Many mathematicians believe that Archimedes already knew the formula before Heron. Some also believe that this formula has Vedic roots and the credit should be given to the ancient Hindus.

What was the French Revolution?

A revolution means a revolt, mutiny or a powerful change.

Origins of the French Revolution

In the years between 1789 until 1799, France experienced the most violent political turmoil, overthrowing the monarchy of Louis XVI and establishing the French republic, only to end in the dictatorship of Napoleon Bonaparte, who was involved in the later years of the revolution.

Causes of the French Revolution

For years, in France, there was a vast difference between the poor and the rich. The rich became wealthier and made merry while the poor struggled for day to day living and became poorer. The poor saw the rich grow; while they got nothing. This angered them and finally a group of poor people rebelled against a few rich in the French society.

Who were involved in the French Revolution?

  • The French society prior to the French Revolution, was ruled by King Louis XVI. For years, in France, there was a vast difference between the poor and the rich. The rich became wealthier and made merry while the poor struggled for day to day living and became poorer.
  • The rich of the French society were called the Nobles who they lived in palaces and were gifted large lands by the King.
  • Then there was another class of people called the Church who owned most of the land in France and they levied heavy taxes on crops which were paid by the common man.
  • The Common Man was the third category of people who not only had to work extremely hard but also had to pay heavy taxes, leaving nothing for their savings or family.
  • The French Revolution was fought between the Common men on one side and the Nobles and Church of the French society on the other.

What led to the French Revolution?

The British colonies of America had declared Independence. France’s costly involvement in the American War of Independence had left France bankrupt. Two decades of poverty and difficulties had left the common man absolutely disillusioned and struggling with inflation due to heavy taxation. This was the beginning of a revolt. A revolution started in 1789 when the common men created a group called the National Assembly. The representatives of the National Assembly had taken an oath that they would not leave until a new constitution has been written for France. The members then attacked the Bastille prison, a symbol of power for the nobles and the King, on 14th July, 1789.

Ten Year Long Revolution (1789 – 1799)

Several other regions of France followed this event and a revolutionary movement was started. There was chaos all over. Peasants burned down castles of the nobles; some wealthy people left their privileges and ran away. There was a wave of violence across Europe known as the Great Fear. The violence kept spreading wherein the members of the third class wanted equal rights for themselves, but the members of the first class did not want to give full rights.

Declaration of the Rights of Man and of the Citizen

It was in August 1789, the National Assembly approved the Declaration of the Rights of Man and of the Citizen. This was the document that stated that all people are born free and have equal rights. The National Assembly also said that peasants will no longer farm for the nobles without pay. They took away the property from the Roman Catholic Church. Most male citizens also got the right to vote.

The Reign of Terror

The French Republic had a group called the National Convention which was later taken over by the Jacobins, an extremist group. The Jacobins began a period called the Reign of Terror. They arrested anyone who was against the revolution and killed many, including King Louis XVI in 1793. It was only in 1795 that a less extremist government called the Directory took over. A new constitution declined the right to vote for all those who could not pay taxes.

What was Napoleon Bonaparte’s involvement in the French Revolution?

During the Revolution, a General named Napoleon Bonaparte became famous. He was a skilled leader and helped expand the territories of France, including a victory over the powerful Austrian Army.

It was in 1799 that Napoleon Bonaparte did away with the Directory and the Revolution came to an end. He made himself the leader of a new government called the Consulate. Napoleon brought peace back to France. He rewrote the old French Feudal laws and created a new Napoleonic Code of laws, which remains in France even to this day.

Napoleon declared himself the Emperor of France in 1804. France became a republic in 1871.

What are synthetic fibres?

Definition of synthetic fibre

Synthetic fibers are man – made from chemicals. They are generally based on polymers and are stronger than natural and regenerated fibers.

Difference between natural and synthetic fibres

Synthetic or man – made fibres can easily be distinguished from natural fibres, such as silk, cotton and wool. Although natural fibres may also be made of polymers like cellulose and proteins, they don’t undergo any chemical changes during the manufacturing process and are used in their original form.

What are synthetic fibres made of?

Synthetic fibres, on the other hand, undergo changes in their chemical structure and composition, during the manufacturing process. Polymers such as regenerated cellulose, polycaprolactam, and polyethylene terephthalate, which have become familiar household materials under the trade names, Rayon, Nylon, and Dacron, respectively, are also made into numerous nonfibre products, ranging from cellophane envelope windows to clear plastic soft-drink bottles. As fibres, these materials are prized for their strength, toughness, resistance to heat and mildew, and ability to hold a pressed form.

Types of synthetic fibres

  1. Polyester is made from esters of dihydric alcohol and terpthalic acid.
  2. Acrylic fabrics are polycrylonitriles.
  3. Rayon is recycled wood pulp that is treated with chemicals like caustic soda, ammonia, acetone and sulphuric acid to survive regular washing and wearing.
  4. Acetate and Triacetate are made from wood fibers called cellulose and undergo extensive chemical processing to produce the finished product.
  5. Nylon is made from petroleum and is often given a permanent chemical finish that can be harmful.

Uses of synthetic fibres

Synthetic fibres play an important role in today’s world and are used either on their own or mixed with other synthetic or natural fibres to create fabrics or products for everyday use. Some uses are :

  1. Ropes
  2. Parachutes
  3. Fish Nets
  4. Carpets
  5. Tents
  6. Fillers in pillows
  7. Fabrics for everyday wear like lycra and spandex
  8. Blankets
  9. Warm and protective clothing for extreme climates
  10. Synthetic hair wigs

Advantages of synthetic fibres

Synthetic fibres are used because of their durable nature. Some of the advantages are :

  • They have good elasticity.
  • They do not wrinkle easily.
  • They are comparatively less expensive, more durable, require less maintenance and are easily available.
  • They are stronger and can handle heavy loads.

Disadvantages of synthetic fibres

  • Most are not heat resistant making them dangerous to wear near fire.
  • They do not allow air circulation, making them sticky, sweaty and uncomfortable to wear, during hot and humid climates.
  • They are non – biodegradable.

The Grand Central Station Facts

Why is the Grand Central Station famous?

The Grand Central Station/Terminal is an iconic American train station in New York City, located at 42nd Street and Park Avenue in Manhattan. It is the largest train station in the world that covers an area of over 48 acres and has 44 platforms and 67 tracks!

What is it like being at the Grand Central Terminal?

As you would enter the grand main concourse, you would find at its centre a circular Information Booth, on top of which is placed the Grand Central’s famous clock which is a four-sided timepiece and is one of the most iconic attractions in New York.

This clock has been a popular meeting point for over a century. This iconic timepiece is made up of expensive Tiffany glass and opal, and is valued somewhere between $10 and $20 million!

Who has painted the iconic ceiling mural at the Grand Central?

About 125 feet up, on the Grand Central Station ceiling, you would see a spectacular mural showing the Mediterranean sky. It comprises of 2,500 stars. This marvellous ceiling was designed by artist Paul Helleu and painted in gold leaf. There are 60 large stars that symbolize different constellations and are illuminated with fibre optics.

11 Interesting facts the Grand Central Station

  1. There is a unique gallery, ‘Whispering Gallery’, where you can whisper a secret to your partner. All you have to do is to stand at one corner of the wall and whisper into; your partner will be able to hear you way across on the other side.
  2. If you are a foodie, there is a series of restaurants and a large gourmet culinary market wherein you will find a wide choice of food items to satiate your taste buds.
  3. For the shopaholics, there are more than 65 stores spread throughout the terminal.
  4. For those who are fond of reading, it even has a spacious and well-equipped library.
  5. The Grand Central Terminal is owned by a private company known as Midtown TDR Ventures.
  6. Grand Central Terminal became functional at midnight on February 2, 1913. It was built on the spot that housed Cornelius Vanderbilt’s railroad network, The New York Central. Acorns and oak leaves are used throughout decorations in the terminal, representing the Vanderbilt family motto: “Great oaks from little acorns grow.”
  7. The estimated construction cost of the Grand Central Terminal is approximately $2 billion.
  8. More than 750,000 visitors pass through the Grand Central Terminal daily.
  9. The Grand Central Terminal is also known as the first ‘stair – less station’ as all levels and platforms within it can be reached by lifts or ramps.
  10. One of the most latest Hollywood movie to feature Grand Central was Men in Black III. A race of tiny aliens was shown being kept inside a Grand Central locker.
  11. It was preceded by Grand Central Depot (1871) and Grand Central Station (1900), both of which were demolished.

Famous quotes about the Grand Central Terminal

  1. There’s something so soothing about the hum of Grand Central Station – Rachel Nichols
  2. Better to get off the train at this station. Than to do it later, when it’s too late. Remember Time doesn’t wait! – Deyth Banger
  3. If you are happy in the station, then the station becomes your train! In other words, if you are happy where you are, it means that you are already travelling! Happiness is a great journey! – Mehmet Murat ildan

‘Grand Central’ Poem by Billy Collins

A poem by Billy Collins (Poet Laureate of the United States from 2001 to 2003), an ode to the 750,000 people that move about daily at The Grand Central Station for the centenary celebrations

The city orbits around eight million
centers of the universe

and turns around the golden clock
at the still point of this place.

Lift up your eyes from the moving hive
and you will see time circling

under a vault of stars and know
just when and where you are.”

John Herschel Glenn Jr Biography

Who is John Herschel Glenn Jr?

John Herschel Glenn Jr, was a military test pilot, selected by NASA for its maiden manned space flight. Part of the Mercury Seven Project, he was a back up to the first two Americans, Alan Shepard and Virgil ‘Gus’ Grissom in space.

John Glenn is remembered as the first American to orbit the earth, circling it three times. At this time, the United States and the USSR were in a race with space programs and Yuri Gagarin from Russia was the first man to orbit the earth.

Early Years – John Herschel Glenn Jr

He was born on 18th July, 1921, in Cambridge, Ohio, to John Glenn, Sr. and Clara Teresa. Glenn studied Science at the Muskingum College, Ohio, and soon after that received his private pilot license in 1941.

In 1942, Glenn joined the United States Navy as a pilot. Thereafter, he switched to the United States Marine Corps. He also served as a fighter pilot in World War II and flew many missions over the Pacific Ocean. In 1943, Glenn married his childhood lady love, Anna Margaret Castor. The couple had two children, Carolyn and John David.

Career in the US Marines

Glenn stayed in the Marines after the war. On July 16, 1957, Glenn set an amazing transcontinental air speed record. He flew a F8U-1 Crusader from NAS Los Alamitos to Floyd Bennett Field, Brooklyn, in 3 hours, 23 minutes, and 8.4 seconds. Glenn was awarded his fifth Distinguished Flying Cross for this mission.

First Man to Orbit Earth Three Times!

In 1958, Glenn joined Project Mercury of NASA. He was the oldest of the seven pilots selected. His task was to fly a Mercury spacecraft called ‘Friendship-7’. His first words when reaching orbit were ‘Zero G and I feel fine.’ He retired from NASA after his flight, and decided to try his luck in politics. He won his first general election in 1974. He was re-elected to the Senate in 1980. Glenn was a popular senator and was re-elected several more times.

Oldest Space Traveller!

In 1998, Glenn went into space again onboard the Space Shuttle Discovery at the age of 77, making him the oldest man to go into space!


He retired from the Senate in 1999. In 2012, Glenn was given the Medal of Freedom by President Barack Obama.


He died at a medical centre after suffering from a ‘serious medical condition’ in Columbus in December 8th, 2016. He was 95 years old at the time of his death.

But he will always be remembered as the first American to orbit space!

3 Interesting facts about John Herschel Glenn Jr

  1. In the Korean War, John Glenn shot down three enemy planes and flew in 63 combat missions.
  2. The only US Senator to have gone into space.
  3. The nickname Friendship-7 was given to the Mercury spacecraft by John Glenn.

Famous quotes by John Herschel Glenn Jr

  • ‘I don’t know what you can say about a day when you see four beautiful sunsets. This is a little unusual, I think’, Glenn said this during his first orbit.
  • ‘To look out at this kind of creation out here and not believe in God is to me impossible.’
  • ‘To me, there is no greater calling, if I can inspire young people to dedicate themselves to the good of mankind, I’ve accomplished something.’
  • ‘We are more fulfilled when we are involved in something bigger than ourselves.’

What is a star?

A star is a luminous sphere of plasma held together by its own gravity. The nearest star to Earth is the Sun. Many other stars are visible to the naked eye from Earth, during the night.

If a star has a planetary system, it maybe referred to as a sun.

There are millions of stars in the universe and astronomers are constantly discovering new heavenly bodies, including new stars and planets.

How are stars formed?

  • Stars are formed in the densest regions of the interstellar medium, called molecular clouds. Molecular clouds are perfect star forming regions because the combination of these atoms into molecules is much more likely in dense regions. Stars are born as clumps within gigantic gas clouds that collapse in on themselves!
  • When a molecular cloud collapses under its own gravity, it forms a denser core which is sustained by nuclear fusion. Nuclear fusion reactions, which take place in the star’s core, support the star against gravity and also produces photons and heat, as well as small amounts of heavier elements.
  • As the cloud’s material heats up, it falls inward under the force of its own gravity. This process goes on for millions of years. As the gases within the star get exhausted, the star starts to cool down slowly and dies eventually.

How do stars die?

Due to its high temperature and intensity, a star is constantly creating materials including helium, silicon, oxygen. As it continues creating, it will eventually start creating iron. When the core turns to iron, it will start to die, as iron is not combustible. It will slowly collapse on itself.

What is the biggest star in the Universe?

R136a1 is the biggest(heaviest) star in the Universe right now! The facts keep changing because of the changing mass of a star or a new discovery!

The R136a1 is a huge star. It’s a member of a star cluster within the Tarantula Nebula, an immense star formation factory located in the Large Magellanic Cloud. It’s believed that the R136a1 contains anything from 265 – 320 solar masses, making it the biggest star known. But it is believed that R136a1 is a star that will probably collapse into itself in a million years.

The other stars that are also big are the Eta Carinae, UY Scuti and NML Cygni.

What is the smallest star in the Universe?

EBLM J0555–57Ab, has been discovered to be the smallest star ever found. Its size is slightly larger than Saturn and it’s about 600 light years away from Earth. It is a part of a binary star system.

The gravity pull of EBLM J0555–57Ab, is 300 times of Earth with a radius of 49,000 kms, 80 percent the size of Jupiter and 85 times the mass of Jupiter. The temperature is lesser than exoplanets discovered. If its size were smaller, it wouldn’t be possible for it to have nuclear fusion reaction required for it to be a star.

What do stars look like?

  • Looking at stars, from earth, it’s impossible to judge what stars look like. Because of a star’s distance and earth’s dense atmosphere, stars appear to twinkle.
  • A star’s colour is based on their age and heat intensity. The hottest stars are blue, and the next hottest are white. Yellow stars are next in heat intensity and red stars are the coolest. Our sun is a green star.
  • Blackholes are stars who have finished being stars and they trap light, instead of emitting it.
  • Sometimes a star shines brighter, simply because it is closer to earth than the other stars.

What are the well known stars and constellations?

  • Polaris, also known as North Star has been a guide for navigation for centuries.
  • Sirius, also known as the Dog Star, has been used by different early civilisations to herald changes in seasons and navigation.
  • Alpha Centauri System is the closest star system to earth.
  • Betelgeuse is 650 light years from Earth. It is also known as the Alpha Orionis and is part of the Orion constellation. It’s a star that is expected to go supernova soon, althought its exact date is not known. And we might be able to see this spectacular event!

9 Interesting facts about stars

  1. Did you know there are runaway stars? Stars that encounter one or two heavier siblings in a massive, dense cluster are pushed out from the cluster by the larger ones. Sometimes, a star may experience being pushed away due to a stellar explosion.
  2. Total number of stars visible to the naked eye are only about 6000.
  3. The Sun is the closest star to us.
  4. Most stars come in multiples and form constellations.
  5. There are between 200-400 stars in our galaxy and that there maybe 500 billion galaxies in the Universe. That’s a lot of stars!
  6. 99 percent of our Solar System is the mass of the sun.
  7. The most massive stars are short lived.
  8. In 185 AD Chinese astronomers were the first to record a supernova, this is now classified as SN 185.
  9. Most stars travel the galaxy with companions or in clusters. But not all stars do that; our Sun, for example, moves through the galaxy without a stellar companion.

Combustion and Flame

What is combustion?

Combustion or burning is a high-temperature exothermic redox chemical reaction between a fuel (the reductant) and an oxidant, usually atmospheric oxygen, that produces oxidised, often gaseous mixture termed as smoke. In some reactions, water is also produced along with smoke and other chemicals.

Types of combustion

Combustion is categorised as the following :

1. Complete and Incomplete Combustion

Complete Combustion –

  • In complete combustion, the reactant burns in oxygen, producing a limited number of products.
  • When a hydrocarbon burns in oxygen, the reaction will yield carbon dioxide and water.
  • When elements are burned, the products are primarily the most common oxides. Carbon will give carbon dioxide, sulphur will give sulphur dioxide.
  • Nitrogen is not a combustible substance when oxygen is the oxidant, but small amounts of various nitrogen oxides form when air is the oxidant.

Incomplete Combustion –

  • Incomplete combustion will occur when there is not enough oxygen to allow the fuel to react completely, to produce carbon dioxide and water.
  • It also occurs if external devices or sources does not allow the combustion to take place completely. Carbon and carbon monoxide are the by products and not carbon dioxide.
  • Certain substances like diesel, oil, plastic, tyres, coal or wood, pyrolysis occurs before combustion. Pyrolysis is the process where complex molecules or polymers are broken down into simpler molecules. Pyrolysis generally occurs without oxygen. It is used in waste management to alter the waste generated into a more usable material.
  • Incomplete combustion adds harmful compounds to the environment, in the form of smog and other contaminants.

2. Smouldering

This type of combustion, though categorised by the presence of incandescence and smoke, produces no flame.

A relatively slow process, smouldering occurs between the oxygen in air and the surfaces of solid fuels such as coal, peat, wood, tobacco and synthetic foams. These solid fuels glow when smouldering, indicating temperatures in excess of one thousand degrees celcius. Sometimes it occurs for some time in a hot environment, despite lack of oxygen. Although under such conditions, it produces high amounts of carbon monoxide.

3. Diffusion Combustion

Diffusion combustion results from the transfer of fuel vapours and oxygen across a concentration gradient into a reaction area that is characterised by high temperatures and correct proportion of reactants. Vapours may come initially from a solid fuel such as candle wax, a liquid fuel like alcohol or kerosene or a gaseous fuel like methane, or even the ordinary LPG cylinders we use in our homes.

The flames produced from diffusion combustion begins as smooth, laminar flame, increasing in turbulence as it grows and consumes more fuel and oxygen.

4. Rapid Combustion

Rapid combustion releases massive amounts of energy in the form of heat and light as is the case with fire. In some cases, combustion occurs so fast that large amounts of gases are released, along with heat and light, causing a significant pressure shift in the surrounding atmosphere. This pressure shift, often accompanied by a very loud noise, is called an explosion.

Internal combustion engines convert the energy produced by rapid combustion into usable kinetic energy.

5. Spontaneous Heating and Combustion

Spontaneous heating and combustion differs from most other types of combustion in that no external ignition source is required for it to proceed. An extremely slow process, spontaneous can take upto a few weeks. It consists of a gradual oxidation of certain material. As heat builds up, the rate of reaction increases, eventually causing smoldering or flaming combustion when the temperature rises. It may occur with petrochemicals, hydrocarbons, hay, cotton, etc.

What is a flame?

A flame is the visible gaseous part of a fire. It is caused by a highly exothermic reaction taking place in a thin zone.

Very hot flames are hot enough to have ionised gases as components, which may be considered plasma.

Structure of a candle flame

A candle flame consists of three zones.

  1. The innermost zone of a flame is dark or black and is the coldest part of the flame and is made of unburnt vapours of combustible material.
  2. The middle zone of a flame is yellow, bright and luminous. The fuel vapours burn partially in the middle zone, because there is not enough air for burning in this zone. The partial burning of fuel in the middle zone produces carbon particles. These carbon particles then leave the flame as smoke and soot. It has moderate temperature.
  3. The outer zone of the flame is blue. It is a non luminous zone. In this zone, complete combustion takes place, as it has enough supply of oxygen.

What is fuel?

Fuel maybe defined as any material that can be made to react with other substances, so that it releases chemical energy as heat.

Classification of fuels

1. Solid Fuel: Coal, wood, charcoal, peat and agricultural waste
2. Liquid Fuel: Kerosene, gasoline
3. Gaseous Fuel: Liquified Petroleum Gas, natural gas
4. Biofuels: Biofuel is defined as derived from biomass
5. Fossil Fuel: Fossils fuels are hydrocarbons, coal, petroleum, natural gas, coal. Fossils fuels are formed from plants dead and fossilised millions of years ago. They are non-renewable sources of energy

What are the characteristics of a good fuel?

The characteristics of a good fuel are :

  • High calorific value
  • Moderate ignition temperature
  • Low moisture content
  • Low noncombustible matter
  • Moderate velocity of combustion
  • Products of combustion not harmful
  • Low cost
  • Easy to transport
  • Combustion should be controllable
  • No spontaneous combustion
  • Low storage cost
  • Should burn in air with efficiency

Uses of combustion chemistry

The study of combustion chemistry helps us to design and monitor better and more efficient machines and engines. It also helps us to avoid using fuels that irreversibly damage our environment.

Urban Administration Facts

What is urban?

An urban area is a human settlement with high population density and infrastructure. They are categorised as cities and towns.

For the Census of India 2011, the definition of urban area is as follows:

1. All places with a municipality, corporation, cantonment board or notified town area committee, etc.
2. All other places which satisfied the following criteria:

a) A minimum population of 5,000
b) At least 75% of the male, main working population is engaged in non-agricultural pursuits
c) A density of population of at least 400 persons per sq. km

What is urban administration in India?

Municipal governance in India has been in existence since 1687, first with the formation of the Madras Municipal Corporation and then Calcutta and Bombay Municipal Corporation in 1726.

By the early 19th century, almost all towns had municipal governance of some type or the other.

With rapid urbanisation, and cities and town contributing to 60% GDP, it becomes very important to develop an efficient urban or municipal governance.

What are the main features of municipal governance?

The main features of municipal governance are :
To create an effective, responsive, democratic, transparent, accountable local governance.
To provide a responsive policy guidance and assistance to sub-national entities.
To strengthen the legal, fiscal, economic and service delivery functions of municipalities.
To foster greater citizen participation in the governance of local bodies.

What is the Nagar Palika Act or the Municipal Act?

The Nagar Palika Act or the Municipalities Act, 1992 set up through the 74th Amendment Act, also provides for a three-tier municipal system in the urban centres. It is similar to the Panchayati Raj system in rural areas.

The Twelfth Schedule of Constitution (Article 243 w) provides an illustrative list of eighteen functions, that may be entrusted to the municipalities. Reservation of seats for ST, SC, OBC & women are similarly provided as in the Panchayati Raj system.

The Nagar Palikas/Municipals are to work as instruments of development and planning and also to handle funds for local activities.

What is the structure of municipal governance of a metropolis?

The structure of municipal governance of a metropolis is as follows :

1. Municipal Corporation

It is the topmost urban local body with a population more than 3,00,000. It is set up under the special statute passed by the respective state’s legislature. Except Delhi, which is the National Capital, the power to set up a Municipal Corporation, lies with the Union Parliament.

2. Councillors

Members of the Municipal Corporation are elected on the basis of universal adult suffrage for a period of five years and they are called Councillors.
These Councillors, collectively called the Municipal Council, exercise deliberative functions and the executive functions are performed by the Municipal Commissioner.

3. Municipal Commissioner and Mayor

The Municipal Commissioner is an Indian Administrative Services(IAS) official appointed by the state government and has executive powers of the government of Municipal Corporations.The other executives known as the Mayor and Deputy Mayor are political executives elected for a period of one year by the members of the Corporation. The Mayor is an honorary head of the corporation and presides over the meetings of the corporation.

What are the functions of municipal corporations?

  1. The Municipal Corporations of cities are involved in providing amenities to the citizens of the city.
  2. Obligatory Basic Amenities
  3. Clean water and construction, and maintenance of water works
  4. Supply of electricity
  5. Road transport services
  6. Construction
  7. City maintenance
  8. Health and life services like crematorium, burial facilities, birth and death registrations
  9. Law and order
  10. Waste and sewage management


  1. Construction of garden, parks, libraries, museums, theatres, and stadiums
  2. Providing affordable, public housing
  3. Planting roadside trees and plants
  4. Providing relief shelters to destitutes and disabled persons
  5. Civil reception VIPS
  6. Registration of marriages, organisation and management of fairs and exhibitions

Rural Administration Facts

What is rural?

The word rural denotes an area that is undeveloped, or under developed. It refers to small settlements which is outside the boundaries of a city, commercial or industrial area and may include countryside areas and villages, where there is natural vegetation. The primary source of income is agriculture and animal husbandry. Cottage and small-scale industries also form a source of income.

In India, a town whose population is below 15000 is considered rural, as per the planning commission.

What is rural administration?

India is made of many states. The states are further divided into districts. The districts are further divided into tehsils(sub-districts) and talukas. Gram panchayat is responsible for looking after such areas, as further they have no municipal board.

Agriculture is the main occupation and lands are sometimes leased on long-term basis for cultivation, by poor farmers. Sometimes land grabbing by people who are powerful also takes place. To settle land disputes or discourage this practice, it is very important to maintain proper land records. Records of the land are maintained by the patwari.

What is a Patwari’s function in rural administration?

A patwari is a person appointed by the local government or land authority to maintain and update land ownership records for a specific area as well as to undertake collection of land taxes. The records maintained by the patwari are used for calculating land revenues.

What is a Tehsildar’s function?

  • Tehsildars are appointed by the Financial Commissioner, and Revenue and Naib Tehsildars by the Commissioner of the Division.
  • The duties of the tehsil office (Panchayat Samiti) exercises certain fiscal and administrative power over the villages and municipalities within its jurisdiction.

The duties of the tehsildar are :

  • They enjoy the powers of Executive Magistrate, Assistant Collector and Sub Registrar/Joint Sub – Registrar.
  • Is Incharge of tehsil Revenue Agency and is responsible for proper preparation and maintenance of tehsil Revenue Record and Revenue Accounts.

What is the function of the District Magistrate?

A district magistrate, also known as district collector, is an officer of the Indian Administrative Services (IAS). They have been empowered as executive magistrates and are also incharge of revenue collection and administration of a district in India.

As an IAS officer, the duties of the district magistrate or collector are very extensive. They are:

As District Magistrate:

  1. Maintenance of law and order.
  2. Supervision of the police and jails.
  3. Supervision of subordinate Executive magistracy.
  4. Hearing cases under the preventive section of the Criminal Procedure Code.
  5. Supervision of jails and certification of execution of capital sentences.
  6. Arbitrator of land acquisition.
  7. Disaster management during natural calamities such as floods, famines or epidemics.
  8. Crisis management during riots or external aggression.

As Collector:

  1. Land assessment
  2. Land acquisition
  3. Collection
  4. Collection of income tax dues, excise duties, irrigation dues etc.
  5. Distribution of agricultural loans
  6. Chairman of the District Bankers Coordination Committee
  7. Head of the District Industries Centre

As Deputy Commissioner/District Commissioner:

  • Reports to Divisional Commissioner on all matters.

As District Election Officer:

  • Conducts Elections in the district, be it General, Assembly or Municipal.
  • Acts as the Returning Officer for the Lok Sabha constituency in the district.

What is the role of a Police Station?

The police have to ensure enforcement of law and order in the area of their charge. In rural areas, sometimes a police station will cover several villages.

Station House Officer (SHO)

A police station is headed by the Station House Officer. In other words, the SHO is the in-charge of the police station. The SHO registers complaints. Complaints are usually registered in the form of an FIR(first information report) and after an investigation by a constable, the SHO may take the help of the Gram Panchayat or village elders in finding a solution. The SHO can also go to the court to reach a solution.

The Hindu Succession Amendment Act, 2005

According to the Hindu Succession Act 1956, daughters did not have any right to ancestral property. This act was amended in the year 2005, to grant daughters the same rights, duties, liabilities, and disabilities that were earlier limited to sons.

What is a natural disaster?

A natural disaster maybe defined as a major adverse occurrence resulting from natural processes of the Earth. The severity of the disasters is measured in lives lost, economic loss, loss to the environment, like in the case of forest fires and the ability of the population for rebuilding or reconstruction.

Effects of natural disasters

Sometimes the loss of property affects the living spaces of people, their transportation, livelihood, and means to live, which is agriculture, communication, irrigation, power projects in both rural and urban settlements.

Sometimes the natural disasters are of such huge scales, that the cost and time involved in reconstructing the infrastructure can affect the economy of the geographical region.

Difference between natural and man made disasters

Man-made disasters are caused due to human error or negligence. Some man-made disasters are so severe, they also set off natural disasters, like loss of the marine ecosystem, animal life, affecting or polluting water resources, destruction of natural resources.


Man Made Disasters

Natural Disasters


Negligence of humans

Natural forces

Types of Disaster

Oil Spilling, Nuclear bombing and testing, Terrorism, Pollution

Tsunami, Floods, Droughts, Wild Fires, Earthquakes, Cyclones etc.


Proper intervention, inspection

education, ensuring safety measures

Regular surveillance, cautionary measures like evacuation, setting up counter-disaster systems, search and rescue, provision of emergency food, shelter, medical assistance etc.

Types of natural disasters

Natural disasters can be classified under the following categories.

1. Earthquakes:

Earthquakes are usually brief but maybe repetitive. They are caused by the sudden release of energy in the earth’s crust, creating seismic waves, which can cause a lot of damage both on the surface and under the surface, sometimes causing landslides. When earthquakes occur in the ocean, they cause tsunamis.

2. Avalanches and landslides:

Avalanches and landslides occur in high altitudes, avalanches specifically in snowy areas and landslides on mountain and hillsides.

They can be triggered by overloading of snow or surface weight, the slope angle, melting snow, rains, or water cascades, and vibrations. Sometimes, they are caused by noise as well, like thunder, or explosions, even shouting or screaming.

3. Sinkholes:

  • Sinkholes are caused by the collapse of large amounts of the earth’s surface into itself, becoming a huge gaping hole in the surface, due to the dissolution of salts, which cause the surface to become weak in places. It is a natural erosion process. It may be caused by torrential rains as well.
  • Sinkholes in the sea offer scuba divers exciting places to explore.
  • Sinkholes are also used as garbage dumping grounds, causing severe damage to groundwater.

4. Floods:

Flooding is the submerging of land not generally submerged, by the overflowing of water. The overflow may occur from a water catchment/reservoir, or from a lake or sea or any other water body.

5. Volcanic eruptions:

Volcanic eruptions occur when a volcano erupts and throws out hot materials like molten rocks(lava), rocks, ash, and dust. Because lava flowing from volcanoes is so hot, it destroys as it flows.

6. Tsunami:

A tsunami or a tidal wave is caused by a large displacement of water, in the ocean. They are seismic waves and do not resemble any other kind of sea wave or currents or tides, which are caused by wind or the lunar cycles. They reach dangerous heights and destroy the coastlines. Japan is prone to tsunamis.

7. Cyclonic storms:

Cyclones are large masses of air, that rotate, spiral around a very strong center with a low atmospheric pressure. It is called a typhoon in Northwest Pacific, a hurricane in Central America. Cyclones can cause severe destruction if they are moving at very high speed, uprooting trees and destroying buildings. They also carry storms and bring in torrential rains, which may cause flooding.

8. Droughts:

Droughts are caused by lack of rainfalls and can cause severe losses to agricultural industry and communities that are dependent on rain and agriculture. Over centuries, droughts have caused several severe famines, causing thousands to die of starvation and suicides.

9. Tornadoes:

A tornado is a rapidly rotating column of air that is in contact with both the Earth’s surface and a cumulonimbus cloud or in some rare cases cumulus cloud. Tornadoes cause severe damage uprooting as they move along at really high speed. They are also known as twisters.

10. Wildfire:

Wildfires or forest fires are uncontrolled fires burning in wildland areas. They can be caused by lightning or volcanic eruptions, or even human carelessness or arson. Wildfires can destroy acres of precious forests which has taken years to grow resulting in loss of both flora and fauna.

What is an Ice Age?

Our planet Earth has experienced several periods of warming and cooling episodes throughout its history. The Ice Age is a period in the Earth’s history that began around 70,000 years ago. As the name suggests, it was a period when the climate was way colder than it is today. In fact, it was the time when most of the Earth’s surface was buried under sheets of ice.

Causes of Ice Age

The geologists believe that the ice age was not caused by one event but a series of factors resulted in the cooling of the Earth, including the planet’s position to the sun, its tilt, and certain changes in the Earth’s atmosphere. Small changes over a very long period of time resulted in such a dramatic change in the climate.

Discovery of the Ice Age

Swiss scientist Louis Aggasiz was one of the first few scientists to study the evidence of the Ice Age. In the mid 1800’s, he told the other scientists that the boulders they saw randomly placed on the Earth’s surface out of nowhere had been left by glaciers. No one believed him and discarded his theory, calling it foolish. They were of the opinion that those boulders were placed there by the Noah’s flood or witchcraft.

Life during the Ice Age

During the Ice Age, the Earth’s surface was completely frozen. This type of barren and cold biome is known as the tundra. Only a few plants, including the evergreen trees, could grow in the frozen soil. The main occupation of men during that period was hunting. Every part of the hunted animals was used for something or the other. Their flesh was used for eating, skins were used as clothing, blankets and shelters and bones were used for making tools and weapons.

Some of the important animals of those times were the woolly mammoth, woolly rhinos, bears, and reindeer. People used to make the pictures of these animals on the walls of their caves. Scientists have also found the frozen fossils of these animals.

Are we living in an Ice Age?

Yes, you would be surprised to learn that we are currently living in an ice age called the Quaternary Ice Age. The Earth is in a warmer stage of the ice age known as the interglacial period. In other words, an interglacial period is a warm period between the cold periods of the Earth where the glaciers are receding.

How many Ice Ages has the Earth experienced?

According to the scientists, the Earth has experienced five major ice ages which are as follows-

  • Huronian – The Huronian Ice Age lasted from about 2400 to 2100 million years ago and was one of the longest ice ages. Scientists believe that the lack of carbon dioxide in the Earth’s atmosphere caused it.
  • Cryogenian – The Cryogenian Ice Age lasted from 850 to 635 million years ago. Scientists sometimes call the Earth during this phase as the ‘Snowball Earth’ also.
  • Andean-Saharan – The Andean-Saharan Ice Age took place between 460 to 430 million years ago.
  • Karoo – The Karoo Ice Age lasted around 100 million years between 360 to 260 million years ago. It is named after glacial tills in Karoo, South Africa.
  • Quaternary – The most recent ice age is the Quaternary Ice Age. It started about 2.5 million years ago and is still going on.

3 Interesting fun facts about Ice Age

  1. Ice Age is not an event that happens quickly. It is actually a very long-term natural phenomenon that lasts for several million years.
  2. The animals that lived during the Ice Ages were generally quite large and fully covered with fur. Scientists also call them ‘Megafauna’.
  3. The famous Disney movie ‘Ice Age’ is based on this period.

What is a landslide and how does it happen?

What is a landslide?

A landslide is defined as the movement of a mass of rock, mud or debris down a slope due to gravity. Landslides cause massive damage to human lives and property while also causing disruption in the movement of traffic and communication network. Landslides block the riverways which may further result in floods also. The productive farm fields that are affected by the landslides may lose their fertility and this causes a massive loss to the farmers.

What causes a landslide?

Landslides are induced by climatic conditions such as heavy rainfalls, snowfalls or natural phenomena such as volcanic activity or earthquakes. Human activities such as deforestation, mining, constructions, vibrations from big machines, etc. may also cause a landslide. Deforestation also is an important cause of landslides. The roots of trees hold the soil in place. Without trees, the stability of a slope is decreased greatly and with a large or even a small change, a landslide can be caused.

Types of landslides

  1. Falls – Falls are sudden movements of huge amount of soil, debris, and rock that breaks away from slopes and cliffs. Such landslides occur as a result of weathering, earthquakes, and force of gravity.
  2. Slides – In this type of a slide, the unstable sliding material breakaways from underlying stable material.
  3. Topples – Topple landslides occur when a block of rock tilts or rotates. It leads to formation of a debris cone below the slope known as a Talus cone.
  4. Spreads – This phenomenon is symbolised by the gradual horizontal displacement of large volumes of distributed material over very gentle or flat terrain.
  5. Flows – This is the most destructive and dangerous form of landslide. Flows have a high water content which loosens the slope material and turns it into a slurry.

Prevention of landslides

Though we cannot prevent natural disasters, we can always make an effort to mitigate their effect. We must encourage people to protect nature, plant more trees and curb deforestation. In addition, detailed geologic investigations, advanced engineering practices and wise use of land can help in reducing landslide hazards.

Landslides in India

Every year, landslides in the Himalayan region kill hundreds of people and cause severe damage to several small villages, leaving them unsuitable for habitation. The main reasons for landslides in India are indiscriminate cutting down of trees, slash and burn cultivation practices in the hills, road construction and mining activities, increased grazing activities, and rapid urbanization. According to data of the Defence Terrain Research Laboratory, “Landslides rank third in terms of the number of deaths due to natural disasters. While Himalayan Landslides kill one person per 100km. The estimated average losses due to landslides in the Himalayas cost 200 lives and Rs 550 crore every year.”

Some of the major landslides that have taken place in India in the last few years are as follows:

  • June 16, 2013 – Kedarnath, Uttarakhand –More than 5,700 casualties were recorded because of this dreadful natural disaster.
  • September 24, 2012 – Northern Sikkim – Over 27 people died in this sad incident, including members of the Indo-Tibetan Border Police (ITBP)
  • July 27, 2007 – Dasalgaon-Maharashtra – The official records suggest 50+ casualties.
  • July 26, 2005 – Raigad – More than 50 people were believed to be dead in this tragedy.
  • July 26, 2005 – Sakinaka, Mumbai – Over 74 people lost their precious lives in this landslide.

3 Interesting facts about landslides

  1. Landslides can move slowly, just a few millimeters per year or can move swiftly with speeds up to 200 miles per hour.
  2. The world’s biggest landslide occurred in 1980 when Mount St. Helens, a volcano in the USA erupted.
  3. The scientists have found out that planets such as Mars and Venus also experience occasional landslides.

Jawaharlal Nehru Biography

Early Life

Pandit Jawaharlal Nehru was the first prime minister of India. He was born on 14th November,1889 in Allahabad. He was born to Shrimati Swarup Rani Thussu and Shri Moti Lal Nehru, a prominent lawyer in Allahabad. He received his early education at home, and later, at the age of 15, he went to England to pursue his higher studies in law. He came back to India in 1912 and started his practice as a lawyer.

Nehru’s role in the freedom of India

Jawaharlal Nehru got married to Shrimati Kamla Nehru in the year 1916, and in 1917, he became the father of a baby girl whom he named “Indira”. Later on, this little girl went on to become India’s first woman Prime Minister. Jawaharlal Nehru was deeply perturbed by the kind of harsh treatment Britishers were giving to his fellow Indians and decided to join the freedom movement. His patriotic heart did not permit him to sit comfortably at home. He joined the Non-cooperation Movement of Mahatma Gandhi and also went to jail several times for flouting the rules of the Britishers. He underwent all the pain and suffering happily for the sake of his country.

Achievements of Pandit Jawaharlal Nehru as a Prime Minister

When India gained freedom in 1947, he became the first Prime Minister of India. As the Prime Minister of India, he took India on the path of progress under his guidance. During his tenure, he brought some changes in domestic, international, economic, agricultural and social policies.

Under his administration, he established several industries, so as to boost our country’s economy and direct it towards development and modernization. He believed that educating the youth of the country was vital for the country’s future growth. Towards this effect, he established numerous institutions of higher learning, including All India Institute of Medical Sciences (AIIMS), the Indian Institutes of Technology (IITs), the Indian Institutes of Management (IIMs) as well as the National Institutes of Technology. He also included free and compulsory primary education for all children in his five-year plan. Despite being an advocate of peace and non-violence, he understood the importance of having a strong defense. He arranged the best modern equipment for the Indian army to safeguard the borders.

Children’s Day

Pandit Jawaharlal Nehru was extremely fond of children and loved them very much. Children also used to fondly address him as ‘Chacha Nehru’. It is because of his love for the children, his birthday- 14th November is still celebrated as Children’s Day in India. Jawaharlal Nehru always emphasized on the importance of giving love and affection to children, and the main purpose of celebrating his birthday as the Children’s Day is to encourage the welfare of children all over the country.

Pandit Jawaharlal Nehru was one of the most popular national and international figures. He is considered as the maker of modern India because of the remarkable changes that he brought in as the first Prime Minister of India. Serving his country, he left for his heavenly abode on 27th of May in 1964.

6 Interesting facts about Pandit Jawaharlal Nehru

  1. Jawaharlal Nehru was the longest serving Prime Minister of the country from the year 1947 till 1964.
  2. Nehru was awarded with the Bharat Ratna award in 1955, India’s highest civilian honor for his outstanding contribution during the freedom struggle and as the first Prime Minister of India.
  3. He wrote many books, including ‘The Discovery of India’, ‘Glimpses of World History’, and his autobiography, ‘Towards Freedom’.
  4. He was also known as ‘Panditji’.
  5. He invented the fashion trend of wearing the “Nehru jacket”
  6. He was extremely fond of roses and always used to clip a bud in his jacket.

Famous quotes by Pandit Jawaharlal Nehru

  1. A moment comes, which comes but rarely in history, when we step out from the old to the new; when an age ends; and when the soul of a nation long suppressed finds utterance.
  2. Time is not measured by the passing of years, but by what one does, what one feels, and what one achieves.
  3. There is perhaps nothing so bad and so dangerous in life as fear.
  4. Action itself, so long as I am convinced that it is right action, gives me satisfaction.
  5. I like being with children and talking to them and, even more, playing with them. For the moment I forget that I am terribly old and it is very long ago since I was a child.
  6. Grown-ups have a strange way of putting themselves in compartments and groups. They build barriers… of religion, caste, colour, party, nation, province, language, customs and of rich and poor. Fortunately, children do not know much about these barriers, which separate. They play and work with each other and it is only when they grow up that they begin to learn about these barriers from their elders.

Read more –
Here’s a full transcript of Jawaharlal Nehru Speech – A Tryst With Destiny

Major Domains of the Earth – Biosphere

The earth is made of four main spheres or domains which play an important part in sustaining life on earth. The spheres combine and interact with each other, to form a complex and intricately balanced system of land, air, water and living creatures’ relationships with each other.

What are the four major domains of the earth?

  1. Lithosphere : The lithosphere is the solid, exterior part of the earth. It is the most rigid of earth’s layers.
  2. Atmosphere : The atmosphere is a complex 500 – 700 km of mixture of gases, including oxygen that we breathe and other elements. These are bound to earth through gravity and so do not disappear into space.
  3. Hydrosphere : The hydrosphere consists of all the water sources on the planet and is interconnected through the water cycle.
  4. Biosphere : The biosphere connects all the existing ecosystem into a network with the other spheres. It is the sphere where all life dwells.

What is biosphere?

The biosphere is a life supporting global ecosystem and is one of the major domains on the planet. In the biosphere, all living things depend on each other, and the existing, surrounding environment, which maybe living or may consist of abiotic factors.

The biosphere is also known as the ecosphere.

When did the biosphere originate?

The biosphere is said to have originated maybe around 3.5 billion years ago and has originated from the abiogenesis process which eventually led to the biogenesis process. The term biosphere was coined by geologist Eduard Suess in 1875. Consequently, Charles Darwin, Matthew F Maury, Vladimir I Vernadsky and Arthur Tansley have contributed towards considerable research to the study of the biosphere. Sir Arthur Tansley introduced the term ‘ecosystem’, in 1935.

How does life sustain itself in the biosphere?

  • Scientists believe that the increase of atmospheric oxygen led to the evolution of the first forms of life.
  • Energy is needed for the function that organisms perform, such as growth, movement, waste removal and reproduction. It is the only requirement that living organisms in the biosphere need apart from what is there in the four major domains.
  • The source of this energy comes from the sun. Plants convert the sun’s energy into food and are very important to the biosphere.

What processes occur in the biosphere?

The organisms in the biosphere are constantly involved in one or more of the following processes :

  1. Decomposition : The breakdown of complex molecules—molecules of which dead organisms are composed – into simple nutrients that can be re-utilized by living organisms.
  2. Energy : Power that can be used to perform work, such as solar energy.
  3. Nutrient cycle : The cycling of biologically important elements from one molecular form to another and back to the original form.
  4. Photosynthesis : Process in which plants capture light energy from the sun and use it to convert carbon dioxide and water into oxygen and organic molecules.
  5. Respiration : Chemical reaction between organic molecules and oxygen that produces carbon dioxide, water, and energy.

What is the Biosphere 2 project?

In order to study the biosphere and the impact of all life forms and the other spheres on the biosphere, scientists set up the Biosphere 2 project. Biosphere 1 is the planet earth.
The artificially replicated Biosphere 2 was set up on three acres, in the Arizona desert, in the 1980s. In 1991, September 26th, a group of four men and four women decided to enter Biosphere 2 for a period of two years. The artificial biosphere contained 3800 species of plants and animals and the human group experimented with growing their food and sustaining and surviving without any other resource.
Although the experiment was one of the first of the longest experiments of living in isolation, it was not successful for several reasons.

Major Domains of the Earth – Atmosphere

The earth is a very complex place. It has been divided into four sphere, to enable us to understand it separately and how each sphere interacts with each other.

What are the four major domains of the earth?

The four major domains are divided as :

  1. Lithosphere Lithosphere is the solid shell of the earth and is divided into a crust and mantle.
  2. Atmosphere – Atmosphere is a layer of gases surrounding a planet, held in place by the gravity of the body.
  3. Hydrosphere Hydrosphere is the combined mass of water present on the surface or under the surface, on a planet.
  4. Biosphere Biosphere also known as the ecosphere, is all the connected ecosystems on a planet and includes all living beings, including their interaction with the other spheres.

What is atmosphere?

Atmosphere is a collection of gases that make the earth habitable.

It consists of 78% nitrogen, 21% oxygen, 1% water vapour and some percentages of trace gases like argon, helium, neon and carbon dioxide. All of these gases combine to form a layer that we refer to as the earth’s atmosphere. It helps protect life on earth by creating pressure, allowing liquid water to exist on the earth’s surface, absorbing ultraviolet solar radiation, warming the surface through heat retention and reducing extreme temperature between day and night.

5 Layers of atmosphere

The atmosphere is comprised of 4 layers, based on temperature, and another layer 500 kms above the earth’s surface, called the exosphere. They are :

1. Troposphere :

The lowest part of the atmosphere, the troposphere contains most of our weather clouds, rain, snow. In this part, temperatures drop by 6.5 degrees celcius, at every km elevation. The sun’s heat is insulated and weathers are created in this layer.

2. Stratosphere :

The stratosphere extends from after the tropopause, the upper boundary of the troposphere. The stratosphere is crucial to life on earth, as it contains the ozone layer, which protects against UV rays from reaching the earth’s surface. Very few clouds are found in this layer. Jets fly in this layer of the atmosphere, to avoid turbulence found in the troposphere.

3. Mesosphere :

The mesosphere is one of the least studied layers of the atmosphere, as flights and balloons do not fly in this layer and satellight are in layers above this one. Meteors that stream into the earth’s atmosphere, are generally burnt up, by the time they reach this layer and cannot travel further. The mesosphere does experience special clouds – noctilucent clouds and the presence of lightning, called elves and sprites.

4. Thermosphere :

  • The thermosphere is the layer of the earth’s atmosphere directly above the mesosphere. The small particles of gas present in the layer absorb x – rays and ultra violet radiation from the sun. Thermosphere means heat sphere, and temperatures in the sphere can go upto 1000 degree celcius.
  • The lowest part of the thermosphere, from 80 km to 600 km and more, is the layer that contains ionised air and is called ionosphere. The sun’s rays in this part of the atmosphere are so strong, they break apart molecules and atoms of air, leaving ions (atoms with missing electrons) and free floating electrons.
  • The ionosphere is the region of the atmosphere where the aurorae occur. Aurorae occurs in both Northern and Southern hemisphere. The phenomenon is known as aurora borealis, or northern lights at the north pole and it is known as aurora australis or southern lights, at the south pole.
  • Aurora is caused by high energy particles streaming out from the sun – the solar wind – striking the earth’s upper atmosphere, or ionosphere. Energy from these electrically charged particles is converted into light, forming visible glows, rays, arcs, bands and veils. The light is generally greenish, but sometimes it is also red. The charged particles are attracted by the earth’s magnetic field. The aurorae are witnessed near the magnetic poles and some distance close to it.

5. Exosphere :

The exosphere is the last layer of the atmosphere. The exosphere extends to 10,000 km above the earth’s surface. In this layer, hydrogen and helium are the main components and particles are constantly escaping into space from this layer of the atmosphere. Several satellites orbit the earth in this layer.

Major Domains of the Earth – Hydrosphere

The earth is the only planet that can sustain and nurture life. This is because of the four domains that make the planet.

What are the four major domains of the earth?

The domains, also known as the spheres are :

  1. Lithosphere : The lithosphere is the solid, outer part of the earth and includes the brittle, upper portion of the mantle and the crust. It is bound by the atmosphere above and the asthenosphere(a part of the upper mantle), below. The lithosphere is the most rigid of earth’s layers.
  2. Atmosphere : The atmosphere consists of 4 layers, and is responsible for the air we breathe, the weather we experience. It also protects us from the sun’s rays and regulates the temperature on the surface.
  3. Hydrosphere : The hydrosphere connects all the water sources on the planet.
  4. Biosphere : The biosphere connects all the existing ecosytem into a network with the other spheres.

What is hydrosphere?

Hydrosphere is the part of the earth which, combines all the water sources on the planet. It includes atmospheric water, oceans, rivers, lakes, groundwater, ice and any other possible source.

The hydrosphere incorporates the water cycle, where water travels from one source to another, changing forms temporarily in between. About 70% of the earth’s surface is covered in oceans which is not potable water. A very small percentage of earth’s water is fresh water.

What is the water cycle?

The water cycle, or the hydrological cycle, takes into account, the exchange of water from the hydrosphere, and cryosphere, which is frozen ice. The continuous movement and exchange of water helps to form currents that move warm water from the tropics to the poles and help regulate the temperature of the earth.

Although several other elements are part of the water cycle, some are useful, like oxygen, while others maybe harmful, like acid rain, algal blooms etc.

Human impact on the hydrosphere

  • The world’s water sources have gotten and are getting even more impacted by human lifestyle.
  • Massive discharge of toxic chemicals, radioactive substances and other industrial wastes, petroleum waste and sewage disposal, seepage of minerals and pesticides into the ground water are all responsible for affecting the quality of the hydrosphere.

Major threats to the hydrosphere

The hydrosphere is affected by excessive pollution of the water sources. This has caused several problems, some of them irreversible. The three major problems are :

1. Eutrophication :

Eutrophication is the excessive dumping of nutrients into water sources. This process induces growth of plants and algae which in turn depletes the oxygen levels in the water, apart from causing other probplems. Eutrophication is almost always induced by phosphate – containg detergents, fertilizers, or sewage in water.

2. Acid rain :

Acid rain is defined as precipitation, with a pH of less than 5.7 that results from reactions involving gases other than carbon dioxide. It has become a world wide problem and is caused by the emission of sulphur di-oxide and nitrogen oxides to the atmosphere by human activities, mainly, fossil fuel burning.

3. Greenhouse gases :

Green house gas emissions from the burning of fossil fuels has led to serious issues. One of them being the increase of global temperatures, which has caused melting of polar ice caps. This has caused the global environment to change considerably.

Environmental problems of hydrosphere

Some issues that we might face in the future if it is left unchecked are :

  • Areas of land might be lost permanently
  • Precipitation patterns may change, causing drastic changes in yearly rains and monsoons.
  • Altitude of clouds may change, causing the overall climate to drop considerably.
  • The pH levels of ocean surface water may change, causing damage to marine life and affecting the marine ecosystem.

Major Domains of the Earth – Lithosphere

The earth is a very complex place. It has been divided into four sphere, to enable us to understand it separately and how each sphere interacts with each other.

What are the four major domains of the earth?

The four major domains are divided as :

  1. Lithosphere – Lithosphere is the solid shell of the earth and is divided into a crust and mantle.
  2. Atmosphere Atmosphere is a layer of gases surrounding a planet, held in place by the gravity of the body.
  3. Hydrosphere Hydrosphere is the combined mass of water present on the surface or under the surface, on a planet.
  4. Biosphere Biosphere also known as the ecosphere, is all the connected ecosystems on a planet.

What is lithosphere?

The word lithosphere is derived from two Greek words, Lithos, meaning rocky and Sphere meaning rigid. Every rocky planet has a lithosphere. The lithosphere is the outermost shell of the planet earth, which consists of the crust and the upper mantle. The upper mantle behaves elastically over thousands of years.

The earth’s lithosphere is divided into tectonic plates. The uppermost part of the lithosphere that chemically reacts to the atmosphere, hydrosphere and biosphere through the soil forming process, is called the pedosphere. The shifting of tectonic plates over millions of years is responsible for the changing earth’s surface.

What are types of lithosphere?

The earth’s lithosphere is of two types : oceanic and continental lithosphere.

1. Oceanic lithosphere

  • It consists mainly of mafic (rich in magnesium and iron) crust and ultramafic (over 90% mafic) mantle and is denser than continental lithosphere.
  • It thickens as it ages and moves away from the mid ocean ridge.

2. Continental lithosphere

  • It is also called the continental crust. It is the layer of igneous, sedimentary rock that forms continents and the continental shelves.
  • This layer consists mostly of granitic rock.
  • The oldest oceanic lithosphere is about 170 million years old compared to parts of the continental lithosphere which are billions of years old.

What is the continental drift?

Under the lithosphere layer, is a molten layer, which is in constant motion. This layer is known as asthenosphere. The lithosphere layers, both the crust and the mantle, are constantly being shaken or disturbed by the movement in the asthenosphere layer. These movements over a period of time, start changing the position of the land masses referred to as continents. This phenomenon, which takes thousands of years is known as continental drift and changes the surface topography of the planet.

Major plates of the lithosphere

  • African Plate
  • Antarctic Plate
  • Eurasian Plate
  • Indo-Australian Plate
  • North American Plate
  • Pacific Plate
  • South-American Plate

World Wide Fund for Nature

What is World Wide Fund for nature?

The World Wide Fund for Nature (WWF) is an international non – government organisation, working in the field of wilderness preservation and towards reducing the impact of humans on the environment.

When was the WWF founded?

It was founded in 1961, by a small group of ardent, mostly British naturalists and conservationists such as Peter Scott, Max Nicholson, Guy Mountfort and Julian Huxley. Initially called the World Wildlife Fund, it retains its official name in Canada and the United States of America.

Where is the World Wide Fund based out of?

WWF was established as a Swiss Foundation and registered in Zurich. Its current headquarters are at Avenue du Mont-Blanc, Gland, Vaud, Switzerland. It is the world’s largest conservation organisation, working in more than 100 countries. It has identified 238 ecoregions, that represent the world’s most biologically outstanding habitats and is working toward those region’s conservation.

Why does the WWF use the Panda symbol?

The WWF giant panda logo originated from a panda named Chi Chi, who had been transferred from Beijing Zoo to London Zoo in 1958. The panda being, an endangered species, with its recognisable iconic features of black and white, made it a strong symbol that could be identified, without language barriers around the world.

It has been modified slightly over the years.

What is the WWF mission?

The WWF work has evolved from saving species and landscapes, to now working with sectors globally, to educate and influence people into making sustainable choices and decisions. The WWF also works with corporates and business and helps make decisions around the use of natural resources.

The WWF work focuses on these areas :

1. Food : With the growing human population, the food requirements of human is increasing rapidly. With this increasing need, man requires more land and resources like fresh water for rearing animals and farming for food which places a considerable strain on land and wildlife and other resources. While efforts to produce adequate amounts of food has been successful, the food doesn’t reach malnourished people. WWF aims to improve efficiency and productivity while reducing wastage and shifting consumption patterns to help conserve our resources and reduce environmental impact.

2. Climate : Our carbon footprint has led to polluted air, acid rains and global warming, which in turn causes polar ice caps to melt, causing several natural disasters. WWF is involved in helping people rethink the way we produce and consume energy, food, water in the present and for the future. It involves changing and redesigning the current public infrastructure and facilities to make it more climate resilient.

3. Fresh Water : The world is facing a huge fresh water crisis. Water is important to all life and there is just 1% of it, that is fresh and accessible. Changing climate, population growth and changing consumption patterns are just a few things affecting fresh water. WWF is committed to partnering with governments, businesses, institutions and communities to ensure healthy fresh water to communities in under developed countries, for wildlife and to provide a sustainable future for all.

4. Wildlife : Ours is a living planet. Saving our wildlife is high on the list of WWF priorities. The 2014 report revealed an astounding decline in wildlife by 52% in the last 40 years. Some species are on the verge of extinction. WWF recovery success stories include southern Africa’s black rhino to black bucks in the Himalayas. All species play an important part in the ecosystem of a region.

5. Forests : Over urbanisation due to pockets of exploding human population, or deforestation to increase farmlands to grow food, has led to extremely huge areas of the earth’s precious forest areas to completely deplete. This has caused changes in temperature, affected rainfalls, changed topography and caused wildlife to go extinct. Loss of our forests will also cause irreplaceable loss to flora and fauna on the planet.

WWF is involved in conserving tropical rain forests, which are the most biologically diverse and complex forests on Earth – forests in the Amazon, the Congo Basin, the Greater Mekong and other regions near the equator. But it also is taking place in temperate regions, such as the Russian Far East and the United States.

6. Oceans : Home to over 2 million species, marine biodiversity far outweighs, life on land. Our oceans regulate global climates, mediate and cause temperature, drought, rainfall. The oceans are also responsible for 83% circulation of the planet’s carbon cycle, making sustaining the ocean a very high priority.

WWF’s oceans work focuses on healthy and resilient marine ecosystems that support abundant biodiversity, sustainable livelihoods, and thriving economies.

What is satire and it’s types

Definition of satire

Satire maybe defined as a genre of literature. A feature of satire is the strong dramatic use of emotions and words to highlight the follies and foibles of humanity, society or an individual.

How is satire used in literature or in art forms?

The four elements of satire are :

  1. Reversal – Satire uses reversal to present the opposite of the normal order. Reversal can focus on the order of events, or the hierarchical order.
  2. Parody – To imitate the techniques and/or style of some person, place, or thing in order to ridicule the original. But it is required to have an original frame of reference for the reader or the audience to understand the parody.
  3. Exaggeration – To enlarge, increase or represent something beyond normal bounds so that it becomes ridiculous and its faults can be seen. Caricature is the exaggeration of a physical feature or trait. Cartoons are an example of this. Burlesque is the ridiculous use of language, for example, characters speak differently and out of character.
  4. Incongruity – To present things that are out of place or are absurd in relation to its surroundings. Particular techniques include oxymoron, metaphor and irony.

Different types of satire

Satire has been in existence since early Roman writing and performance arts. The word satire is derived from the phrase, lanx satura, meaning medley.

The Roman writers Horace (Horatian Satire) and Juvenal (Juvenalian Satire) by their practice have left an indelible mark on formal satirical verse writing. Through their writings, they devised loosely defined rules of satire.

Roman satire is of two types – Comical satire and tragical satire

Nicolas Boileau, Dryden and Alexander Pope’s writings in the 17th and 18th century have contributed to the modern age of satire, influencing satire writing styles.

Although satire is a complex writing form and difficult to classify, it is classified based on the writers who have contributed significantly, on the medium that it is conceived for and the topics that it depicts.

Satirical writings have also been discovered in ancient Egyptian papyrus rolls, dating from 2nd millennium BC.

The Greeks had no formal word for satire, although the term cynicism and parody has been used in writings. Greek playwright Aristophanes, is one of the best known early playwright.

Menippean satire

Another type of satire is Menippean satire which is usually in the form of prose with its central focus on mental attitudes and not individuals or entities. It is named after the Greek parodist Menippus. His works have influenced other early Greek and Roman writers.

Difference between Irony, Sarcasm and Satire

  • Irony – Irony maybe defined as describing situations that are strange or funny because things happen, in a way that seems to be the opposite of what an audience or reader expects.
  • Sarcasm – Sarcasm depends on addressing an issue indirectly and generally uses a comparative point of reference. It uses bitterness, rudeness, harshness to drive a point.
  • Satire – Satire uses emotional or attitudinal exaggeration humour to ridicule a situation or a society or an individual.

Famous works in satire

  • The Animal Farm
  • Don Quixote

Masai Mara National Reserve

Where is Masai Mara national reserve located?

The Masai Mara National Reserve, known by the local inhabitants as the Mara, is a large game reserve in the Narok County, Kenya. It shares its borders with the Serengeti National Park in the Mara Region, Tanzania. It lies in the Great Rift Valley, which is a fault line, some 5,600 kilometers from Ethiopia’s Red Sea.

Mara, which is Maa, in Masai language is translated as spotted, as it describes the landscape, with cloud shadows, circle of trees, scrub, savanna, which cover the area.

Masai Mara safari

The Masai Mara is one of the most visited natural wildlife reserves, with adventure safaris, but it also suffers from local poachers and international trophy game hunters.

The Masai are the ancestral inhabitants of the Mara.

Who are the Masai people?

  • The Masai people are Nilotic ethnic group inhabiting the Kenyan and Tanzanian savannas. They speak the Maa language and Swahili, Kenyan and Tanzanian.
  • They are pastoralists and have inhabited the grasslands and chosen to live with the wild animals, without hunting them, being one with the land.

What kind of animals inhabit the Masai Mara?

  • The Masai Mara is one of the world’s finest wildlife destinations. It is home to one of the oldest, most diverse and expansive ecosystems on the planet.
  • It is also home to the Big 5, the world’s most sought after wild animals, dangerous and difficult to hunt by colonial hunters, which are the African Lion, Elephant, Rhino, Leopard and the Buffalo.

Great migration of the Masai Mara

  • One of the spectacular events to occur in the Mara is the annual Wildebeest migration, one of the largest overland migration in the world.
  • The Great Migration sees over 1.5 million Wildebeest, 200,00 Zebra and a host of other Antelope travelling cross country. This occurs around July, each year.

4 Interesting facts about Masai Mara National Reserve

  1. It was officially established as a reserve in 1961, as a wildlife sanctuary and covered only 520 square kilometers(200 square miles) of the current area. Today it covers 1,510 square kilometers area.
  2. Apart from the Big 5, the most dangerous and difficult to hunt animals, the Masai Mara also has animals which form a part of the wildlife, like the Hyena, Cheetah, Eland, Gazelle, Topi, Thomson’s Gazelle, Vultures, Hippos etc. Hippos are abundant in the Mara River, as well as very large Nile crocodiles.
  3. The Wildebeest are the largest inhabitants of the Masai Mara. More than 470 species of birds are found in the Masai Mara, many of them migrants. Species such as Eagles, Stork and Vultures are among the more than 50 birds of prey.
  4. There are more than 4 types of topography in the Mara. They are : Ngama Hills, Oloololo Escarpment, the Mara Triangle and the Central Plains.

World Trade Organisation

What is the World Trade Organisation?

The World Trade Organisation is an inter – governmental organisation that regulates international trade. It has been created to ensure that trade occurs smoothly, predictably and as freely as possible. WTO agreements have been negotiated and signed by a substantial number of the world’s trading nations and has been ratified in their parliaments.

How was the WTO conceived and why?

The World Trade Organisation was conceived and created to handle trade negotiations.

Initially conceived as ITO, but functioning as GATT, it continued to be one of the key pillars of Post World War 2 economic reconstruction and development. This is before WTO came into being.

GATT proved to be highly successfully in liberalising world trade. By the mid 1980s, there was a need for a stronger multilateral organisation to monitor trade and resolve trade disputes. Following the Uruguay Round, (1986 – 1994) of multi trade negotiations, World Trade Organisation began its operation.

Why did GATT change to WTO?

WTO is a successor to the General Agreement on Tariffs and Trade, GATT created in 1947. GATT had been created in the hope that a specialised United Nations agency called International Trade Organisation (ITO) would materialise. GATT was successful for five decades, despite non – materialisation of ITO.

WTO began operations on January 1, 1995, under the Marrakesh Agreement signed by 123 countries. By 2010, World Trade Organisation had more than 160 members.

What are the objectives of WTO?

World Trade Organisation has six set objectives. They are,

  1. To set and enforce rules for international trade
  2. To provide a forum for negotiating and monitoring further trade liberalisation
  3. To resolve trade disputes
  4. To increase the transparency of decision-making processes
  5. To cooperate with other major international economic institutions involved in global economic management
  6. To help developing countries benefit fully from the global trading system

WTO focuses on all goods, services and intellectual and some investment policies, as well.

Organisational structure of WTO

The General Council has the following subsidiary bodies that oversee several committees and agencies. They are :

  1. Council for Trade in Goods : There are 11 committees under this Council’s jurisdiction
  2. Council for Trade : Related Aspects of Intellectual Property Rights : These work in recording the intellectual property information within WTO and other international organisations.
  3. Council for Trade in Services : The Council operates under the guidance of the General Council and is responsible for overseeing the functioning of the General Agreement on Trade in Services (GATS). It is open to all WTO members and can create subsidiary bodies as required.
  4. Trade Negotiations Committee : Deals with current trade talks.

What purpose does World Trade Organisation serve?

  • WTO attempts to protect small and weak countries against discriminatory trade practices of large and powerful countries.
  • Secondly, it also requires members to limit trade only through tariffs and to provide market access not less favourable than that specified in their schedules.
  • It also enables to help governments resist lobbying efforts by groups claiming special favours on trade.

What is WTO’s role in resolution of trade disputes?

  • Just like GATT before it, WTO plays a very strong role in helping settle trade disputes. Members are commited not to take unilateral or one sided decisions, against other members. Instead they are expected to seek to settle issues with the dispute settlement system and to abide by its rules and findings.
  • Resolution of Trade Disputes begin with bilateral consultations, through the mediation, or good offices. If this does not work, an independent panel is created to hear the dispute.
  • All settlements have to finish within nine months and are settled as per the rules set by the Appellate Body, unless a consensus exists among the members against doing so.

Difference between vertebrates and invertebrates

What are vertebrates?

Vertebrates are animals with a spinal column and an elaborate skeletal structure.

Characteristic traits of vertebrate animals

Vertebrates have the following characteristics:

  1. All vertebrates have muscles and skeletons that help them to move around easily and perform complex moves.
  2. All vertebrates also have an endoskeleton, which consists of the bones that are inside a body which gives them their shape and allows them to stand erect.
  3. All vertebrates have some or all of these systems : muscular system, skeletal system, excretory system, immune system and nervous system, and skin covered with scales, fur, hair, or feathers.

Classification of vertebrates

Vertebrates are further classified into five classes. They are:

1. Pisces – fishes

  1. They are cold-blooded animals
  2. They have streamlined body
  3. They have gills to breathe and fins for movement
  4. In most of the cases, the body is covered with scales which provide protection to the body

Example – Goldfish, Seahorse, Shark

2. Amphibia – frogs and salamanders

  1. They are cold-blooded animals
  2. They can live both on land and in water
  3. They breathe through both lungs and moist skin
  4. They reproduce only in water

Example – Toad, Frog, Salamander

3. Reptilia – lizards and snakes

  1. They are cold -blooded animals
  2. They live on land
  3. They breathe with the help of lungs
  4. They have dry and scaly skin
  5. They lay eggs

Example – Snake, Turtle, Crocodile

4. Aves – birds

  1. They are warm blooded animals
  2. Their body is covered with feathers
  3. Their forelimbs are modified into wings
  4. They breathe through lungs
  5. Their bones are hollow
  6. They lay eggs

Example – Pigeons, Parrot, Peacock

5. Mammals – animals with mammary glands

  1. They are warm blooded animals
  2. They breathe through lungs
  3. They give birth to babies
  4. They have mammary glands to produce milk

Example – Human, Dog, Cat

What are invertebrates?

Invertebrates are animals without a spine. They have no vertebrae.

Characteristic traits of invertebrate animals

Invertebrates have the following characteristics:

  1. They are multi-cellular and all the cells are assigned different tasks
  2. They have no cell walls
  3. They reproduce by two reproductive cells or gametes

Classification of invertebrates

1. Sponges – poriferans

  1. They are known as sponges
  2. They live in salt water fixed to some object
  3. Their body is covered with pores through which their food enters

Example – Sycon, Spongilla

2. Cnidarians

  1. They live in the marine habitat
  2. The body is like a tube with one opening called mouth
  3. Mouth is surrounded by tentacles that help in capturing prey
  4. They have a radially symmetrical body

Example – Hydra, Jellyfish

3. Platyhelminthes – flatworms

  1. They can be found in marine/fresh water
  2. They have flat, ribbon shaped body
  3. The body is bilaterally symmetrical
  4. The body has a single opening
  5. Most of them are parasites

Example – Tapeworms, Liverfluke

4. Nemathelminthes – roundworms

  1. They are found in fresh/marine water or on land
  2. They have a thread like, rounded body
  3. They have an unsegmented body
  4. Their body has two openings, mouth and anus
  5. The body is bilaterally symmetrical
  6. Most of them are parasites and reproduce sexually by laying eggs

Example – Pinworm, Ascaris

5. Annelids – segmented worms

  1. They are found in marine and fresh water
  2. They have segmented bilaterally symmetrical body
  3. They have a body cavity
  4. They have special organs of excretion known as Nephridia

Example – Earthworm, Leech

6. Arthropods – animals with jointed legs

  1. They have a segmented, bilaterally symmetrical body
  2. Their body is divided into three parts – Head, Thorax and Abdomen
  3. It is covered by a tough outer covering called exoskeleton
  4. They have jointed appendages

Example – Ants, Honeybee, Scorpion, Spider

7. Molluscs – soft bodied shelled animals

  1. Animals have a soft unsegmented body with an external hard shell

Example – Squid, Snail, Octopus

8. Echinoderms – spiny-skinned animals

  1. They live in the marine environment and have spines all over the body
  2. The body is radially symmetrical
  3. Their body has two openings, mouth and anus
  4. They have tube like feet having suckers

Example – Starfish, Sea Urchins

5 Fun facts about vertebrates and invertebrates

  1. Different types of vertebrates have different numbers of vertebrae. Humans have 33 vertebrae, an alligator has 66 vertebrae, and a snake has about 500 vertebrae!
  2. Vertebrates have advanced nervous system, therefore, they are much more intelligent than invertebrates.
  3. Invertebrates cannot make their own food, and therefore, they have to feed off other things to get their energy.
  4. Mammals and birds are warm-blooded, which means that they can make their own body heat even when the temperature outside is low. The body temperatures of warm blooded animals usually stay the same.
  5. The body temperature of the cold-blooded animals, like reptiles, fish and amphibians depends on the temperature outside. For example, when the sun sets at night, their bodies become cold and when the sun rises, their bodies become warmer.

What is electromagnetism?

Definition of electromagnetism

Electromagnetism is the type of magnetism produced by an electric current. This phenomenon was discovered in 1819 when a Danish scientist named Hans Oersted noticed the needle on a magnetic compass moved if it was put close to an electric wire.

Before his discovery, scientists believed that electricity and magnetism were two different scientific phenomena. Then, in 1825, an English physicist named William Sturgeon created the first use – able electromagnet that could easily lift a 9 pounds iron piece.

What is an electromagnet?

An electromagnet is a magnet whose magnetic field is created when electricity is flowing. This type of magnet is different from the refrigerator magnets that you use to decorate your refrigerator. A refrigerator magnet is a kind of permanent magnet made of magnetic material that continuously generates a magnetic field. On the other hand, electromagnets are built and produce a magnetic field only when required.

Difference between a permanent magnet and electromagnet?

Permanent magnet

  1. The South – North polarity of a permanent magnet is fixed. It cannot be changed.
  2. Its strength cannot be altered.


  1. The South – North polarity of an electromagnet can be altered by changing the direction of the current in the coil.
  2. Its strength can be altered by changing the current flowing in it or by changing the number of turns in it.

How is an electromagnet made?

When an electric current flows through a wire, it generates a magnetic field. The magnetic field can be increased by coiling the wire. This allows more current to flow through a smaller distance and increases the magnetic field. The direction of the current determines the direction of the magnetic field.

Right hand rule and electromagnetic field

When electricity flows in a long straight wire it creates a circular or cylindrical magnetic field around the wire according to the right-hand rule, which means the fingers show the direction of the electromagnetic field generated and the thumb points to the direction of flow of electrons or current.

How to make an electromagnet?

Not every material can be used to create an electromagnet. A naturally magnetic material like nickel, cobalt or iron, has to be used. Any of these three materials or their mixtures are used with a solenoid and a battery to create an electromagnet. You too can make your own electromagnet at home by following the given instructions:

Making a simple electromagnet

All of you know that a nail is not a magnet. However, it can be turned into one if you wrap a wire coil, called a solenoid, around it.

Material required –

  • A battery
  • Paper clips
  • Nail
  • Copper wire

3 Steps to make a simple electromagnet

  1. Wrap the copper wire onto the nail. Make sure that the wire-coils are very close and tight.
  2. Wrap the copper wire ends tightly to the top of the battery on both sides where the positive and negative charges are located.
  3. Now, move the contraption on the top of the paper clips that you have. You would be able to easily lift them without touching them. This is electromagnetism at work!

6 Uses of electromagnetism

  1. Electromagnets produce much more powerful magnetic fields than permanent magnets. The power of the electromagnets can be adjusted by changing the amount of current flowing through it. Electromagnets find their uses in many things that we use in our everyday lives.
  2. They are used in cell phones that work on the interaction between the phone signals and magnetic pulses produced by an electromagnet inside the phone.
  3. Electromagnets are also used in magnetic resonance imaging (MRI) machines that help us to look inside the human body.
  4. Loudspeakers use electromagnets to produce sound.
  5. Electromagnets make it easy to handle large chunks of scrap metal via cranes.
  6. Modern generators also require electromagnets to function efficiently.

What is World Bank?

The World Bank is an international organisation dedicated to providing finance, advice and research to developing nations to aid their economic advancement.

The Bank predominantly acts as an organisation that attempts to fight poverty by offering developmental assistance to middle class and poor income countries for capital programs.

How does the World Bank work?

The World Bank is based in Washington DC. The United States and United Kingdom are the two most powerful countries in attendance and dominate negotiations.

The largest shareholders of the World Bank are France, Germany, Japan, United Kingdom and United States of America. The other countries’ presence as shareholders is based on the size of their economy.

The President of the World Bank

Although the Presidents of the World Bank have traditionally been American, there have been a few instances of non – American presidents.

Current president of the World Bank

The current 12th President is Jim Yong Kim, a South Korean born American physician, who is serving his second term. His development priorities include launching several innovative financial instruments including facilities to address infrastructure needs to prevent pandemics and help millions of people forcibly displaced from their homes by climate shocks, conflict and violence.

How is the World Bank organised?

Due to growing membership and needs, the World Bank expanded and consists of five different agencies which are :

  1. The International Bank for Reconstruction and Development – Funded by sales of bonds in international capital markets, the IBRD provides assistance to middle income countries.
  2. The International Development Association – Provides policy advice, interest free loans and technical advice to countries with a per capita income lesser than $885.
  3. The International Finance Corporation (IFC) – Finances private sector investments.
  4. The Multilateral Investment Guarantee Agency (MIGA) – Helps encourage foreign investments and investment opportunities, by providing guarantees to foreign investors against loss caused by non – commercial risks in developing countries.
  5. The International Centre for Settlement of Investment Disputes – Settles any disputes that may arise between foreign investors and host countries.

Industrial Revolution Timeline

What was the start of the industrial revolution?

Britain was the first country to experience modern industrialisation. Apart from the fact that Britain was well connected to Europe and rest of the discovered world, it also had ample supply of fuel and raw materials, like iron and labour from increasing population, especially in cities.

Coal played a very important part in the Industrial Revolution because most machines were powered by it, but the burning of coal intensified air pollution in the cities. Now let us come to iron!

The industrial revolution begins

At the beginning of the 18th Century, iron makers found a way to extract pure iron out of iron ore. Soon, industries started producing enough iron to make machines, water pipes, engines and rails etc. that were required for the development. The mass production of goods called for new methods of transportation. New roads and a system of canals carried products made in factories to markets all over the world. The process of spinning raw cotton into thread and weaving of thread into fabric completely revolutionized the textile industry.

Impact of the industrial revolution

Though the European countries were getting wealthier, the labourers who actually produced goods were living in deplorable conditions. As more and more people were flocking to the cities from villages in search of job opportunities, there was a gross dearth of accommodation. The workers were forced to live in small, dingy houses which also led to the spread of communicable diseases. Many people died because of fatal diseases like cholera, plague and typhoid. Small children of your age were also made to work in the factories. The working hours were long, salaries were very less and there were no holidays. The air was filled with black smoke from the factories chimneys and the pollution was at its peak causing huge damage to the environment.

Important inventions during the first industrial revolution and their inventors

James WattFirst Reliable Steam Engine1775
Samuel F. B. MorseTelegraph1836
Elias HoweSewing Machine1846
Isaac SingerImproves on Howe’s Sewing Machine1851
Werner von SiemensElectric Dynamo1866
John MacadamSafer roads with stones1820
James HargreavesSpinning Jenny1770
Samuel CromptonSpinning Machine1779

How many industrial revolutions have we had?


As we just read, the first industrial revolution spanned from the end of the 18th century to the beginning of the 19th century. It witnessed the appearance of mechanisation that replaced agriculture with industry. Non – renewable sources of energy like coal and iron were the heroes that facilitated this change. Important events were the invention of the steam engine, development of railroads, acceleration of trade, and birth of the first factories and cities as we know them today.


At the end of the 19th century, new sources of energy like electricity, gas and oil surfaced and initiated the second industrial revolution. The steel industry began to develop and grow. Chemical synthesis also developed and introduced us to different synthetic fabrics, dyes and fertilizers. The invention of better means of communication like the telegraph, the telephone and advanced means of transportation like automobiles and planes also came into existence.


In the latter half of the 20th century, a third industrial revolution appeared with the advent of nuclear energy. This revolution saw the rise of electronics such as transistors and microprocessors, and computers. The modernisation of technology led to the production of miniaturised material which played an important part in furthering space research and biotechnology.


The fourth industrial revolution is taking place before our eyes. Its origin lies in the emergence of the Internet which has helped us to create a new virtual world from which we can manoeuvre the physical world. There is a growing concern about the environment and factories of tomorrow will hopefully be powered by renewable sources of energy such as wind, sun and geothermal energy. That would be great, right?

Srinivasa Ramanujan Biography

Ramanujan’s early years

Srinivasa Ramanujan was one of the most famous mathematical wizards who made important contributions to the field of advanced mathematics. Srinivasa Ramanujan was born on 22 December, 1887, to a poor Brahmin family in Erode, a small village in Tamil Nadu, India.

He grew up in Kumbakonam town, near Chennai, where his father was employed as a clerk in a cloth merchant’s shop. He was an exceptionally good student and won a number of merit certificates and awards. He loved Mathematics more than any other subject.

Once, when he was just in his middle school classes, he mathematically calculated the approximate length of the equator. He also very clearly knew the values of the square root of two and value of pi!

Srinivasa Ramanujan – Education and work

  • At the age of 16, he got a scholarship for his first year at the Government College in his hometown. His deep interest in Mathematics led him to neglect other subjects because of which he was not able to clear his examinations and had to forgo his scholarship. After dropping out of college, he had to struggle a lot to earn his living.
  • However, it did not dampen Ramanujan’s spirits and he continued to work on problems and theorems. He bought a book authored by G. S. Carr which contained over 5000 problems. He worked and reworked all the problems and theorems and made new discoveries. He also found a job as an accounts clerk in the office of the Madras Port Trust.
  • Then, he got in touch with V. Ramaswamy Aiyer, the founder of the Indian Mathematical Society. With his help, Ramanujan got his paper on Bernoulli numbers published in the ‘Journal of the Indian Mathematical Society’ in 1911. Soon, he became a quite popular in Chennai for his prowess in Mathematics.
  • In 1913, he casually wrote to the well-known Cambridge mathematician, G. H. Hardy, and told him about his work. Hardy was mighty impressed with Ramanujan’s works and assisted him in getting a grant from Trinity College, Cambridge.
  • Ramanujan moved abroad and started to work in collaboration with Hardy, but his health started failing. Despite poor health, he remained engrossed in his research and study of newer vistas in mathematics. In 1916, he graduated from Cambridge with a Bachelor of Science by Research.
  • In 1920, he moved back to India and left for his heavenly abode.

What is Srinivasa Ramanujan famous for?

  • Despite having almost no formal training in Mathematics, Ramanujan’s knowledge of the subject-matter was astounding. Without the knowledge of the modern developments in the subject, he had made some important contributions to the field of mathematical analysis, number theory, game theory, infinite series and continued fractions.
  • He was a luminary who rose to great heights from a humble background and followed his heart against the odds in his way. His innovative ideas and vision still serve as a great resource for modern mathematicians.

The Man Who Knew Infinity

In the honour of Ramanujan, December 22 is now celebrated as the National Mathematics Day in India. His biography titled ‘The Man Who Knew Infinity‘ was published in 1991 and a movie based on him starring Dev Patel was also shown at the 2015 Toronto Film Festival.

Famous quotes by Srinivasa Ramanujan

  1. An equation means nothing to me unless it expresses a thought of God.
  2. I have not trodden through a conventional university course, but I am striking out a new path for myself. I have made a special investigation of divergent series in general and the results I get are termed by the local mathematicians as “startling.”

What is scattering of light?

Scattering is the phenomenon by which a beam of light is redirected in many different directions when it interacts with a particle of matter.

What is the difference between scattering of light and just normal reflection?

Scattering occurs when a particle of light is fully absorbed and then emitted, while reflection is when a wave/particle is simply reflected off the surface without interacting.

What is the difference between scattering of light and just normal refraction?

Refraction is the bending of light as it crosses different transparent/translucent mediums, and doesn’t experience any change except it bends. In scattering, light experiences a change in its properties.

How does light scattering work?

When light experiences particles on its path, it is scattered by the particles, it encounters. The intensity of the scattered light depends on the size of the particles and the wavelength of the light.

Light scattering theory

According to Rayleigh theory, a theoretical description of light scattering involving particles much smaller than the wavelength of the light, makes the sky blue.

When light meets a molecule smaller than its wavelength, the electric fields temporarily polarise the molecule, re-distributing the electrons in the molecule such that one end has a weak positive charge, and the other has a weak negative charge. This separation of charges is called a dipole moment. As the oscillating electric fields interact with the molecule, the molecule’s dipole moment oscillates and the molecule re-radiates the light in all directions.

Rayleigh scattering can be considered to be elastic scattering since the photon energies of the scattered photons do not change.

Molecules with larger sizes than the wavelength of the light , experience scatter differently. They experience what is known as the Mie Effect. Since the particles are bigger, the light appears white. This is why clouds, which are made of droplets of water appear white.

These principles are sometimes used to calculate molecular mass.

Why do shorter wavelengths scatter more?

Shorter wavelengths and higher frequency scatter more because, the more wavy the line, the more chances it has of intersecting with a particle. Longer wavelengths have lower frequency and so have less chances as they are straighter and chances of colliding or intersecting with a particle is less.

Why is the sky blue?

The colour of the sky is blue because of the shorter wavelength and the length of the path. The colour of the sky changes as the path distance changes.

What is a Chromosome?

Definition of Chromosome

The word chromosomes is derived from two words, Chroma, meaning colour and Soma, meaning body. This is because when they were first discovered, they had used very strong colour dyes to detect them.

What are chromosomes made of?

They are thread like structures, located inside the nucleus of cells of both plants and animals. Each chromosome is made of protein and single molecule of DNA (Deoxyribonucleic Acid). DNAs are responsible for carrying forward the genetic make up of an individual plant or animals and so the species.

In humans, animals, and plants, most chromosomes are arranged in pairs within the nucleus of a cell. Humans have 22 of these chromosome pairs, called autosomes.

What does a chromosome structure look like?

  • Chromosomes tend to show up only when the cell is undergoing cell division.
  • Chromosomes are made of DNA that are tightly coiled around positively charged proteins called histones. This is to condense the DNA material.
  • On each chromosome, there is a constriction point known as the centromere, that separates into four arms. The centromere plays an important role in the overall shape of the chromosome and can be used to locate a specific gene. Short arms are called p arms and long arms are called q arms. This gives the chromosome an X like appearance.
  • Studies have shown that chromosomes without centromeres, segregate randomly, are eventually lost from cells. On the other hand that have multiple centromeres tend to fragment, causing genetic mutations and disorders.

4 Types of chromosomes

1. Metacentric Chromosome

Metacentric chromosomes have the centromere in the center, such that both sections are of equal length. Human chromosome 1 and 3 are metacentric.

2. Submetacentric Chromosome

Submetacentric chromosomes have the centromere slightly offset from the center leading to a slight asymmetry in the length of the two sections. Human chromosomes 4 through 12 are submetacentric.

3. Acrocentric Chromosome

Acrocentric chromosomes have a centromere which is severely offset from the center leading to one very long and one very short section. Human chromosomes 13,15, 21, and 22 are acrocentric.

4. Telocentric Chromosome

Telocentric chromosomes have the centromere at the very end of the chromosome. Humans do not possess telocentric chromosomes but they are found in other species such as mice.

How many chromosomes does a human cell have?

  • Human cells have 23 pairs of chromosomes, making a total of 46 chromosomes. Of these, 22 pairs are called autosomes and look the same in both male and female humans.
  • In females, the 23rd pair has two X shaped chromosomes.
  • In males, the 23rd pair has one X and one Y chromosome.
  • The sex or the reproductive cells, the gametes, have 23 chromosomes out of which the sperm cell will carry an X or a Y chromosome. The egg will carry 23 chromosomes, out of which the 23rd will be an X. This is a haploid cell.
  • On fertilization of the egg, depending on the 23rd chromosome, the gender of the zygote is decided. The zygote will carry 46 chromosomes. This is known as a diploid cell.

Why are chromosomes so important?

Chromosomes are important to ensure that when cell duplicate or undergo cell division, to produce new cells, they carry the genetic information accurately to the next generation of cells, and hence the organism. This keeps the genetic information intact and is important to keep the species alive. It is also important for cells of organs to regenerate.

What is a chromatid?

A chromatid is one of the replicated copies of a chromosome. Identical sister chromatids are produced as a result of DNA replication.

In contrast, homologous chromosomes are derived from either the mother or the father of the organism. Although they contain the same set of genes, they usually have genetic differences.

Do bacteria and viruses have chromosomes?

  • Bacteria and virus have simplified chromosome structures.
  • In bacteria or prokaryotes, the chromosome is dispersed within the cell and is not enclosed by a separate membrane. It is called a nucleoid. It is also common for bacterial species to have to possess extrachromosomal genetic elements called plasmids. Plasmids play a major role in drug/antibiotic resistance and hence spread of bacteria borne diseases.
  • Virus on the other hand have very basic, fragments of genetic material inside the protein coat or shell. The shell is called capsid.

What is Ohm’s Law?

Definition of Ohm’s law

Ohm’s Law is the mathematical relationship between electric current, resistance and voltage.

Ohm’s law states that the current through a conductor, between two points is directly proportional to the voltage across the two points.

The principle is named after the German scientist Georg Simon Ohm.

Ohm’s Law formula

The formula for Ohm’s Law is as follows:

V = IR


V is Voltage
I is Current
R is Resistance

How does Ohm’s Law work?

A continuous flow of free electrons, through the conductors of a circuit is called current. An electric circuit is formed when a conductive path is created to allow the free electrons to continously move.

The force that is motivating the flow of electrons is called voltage. It is a specific measure of potential energy that is always relative between two points.

Free electrons tend to move through conductors with some degree of friction, or opposition to motion. This opposition to movements of free electrons is called resistance.

Using this Law, we are able to analyse electric circuits. If you know any two values, you can analyse the third one. Sometimes electric circuits are complicated, but this equation is so important, it solves those complicated circuit values as well. It is applied in almost all circuit studies.

Practical application of Ohm’s Law

  1. Ohm’s Law is used in electrical heaters to generate heat. The conductor is designed to create resistance to the flow of free electrons and so the resistance creates heat.
  2. Ceiling and other fans, use Ohm’s Law as well. The speed is regulated using Ohm’s Law application.
  3. Light Bulbs emit light using Ohm’s Law

Here is a simple, fun exercise. Walk around your house and see which object uses Ohm’s Law! Make a list and compare it with your friends. Have fun!

Simple Interest and Compound Interest

What is interest?

  • Interest is the rate at which money is borrowed. It is used in accounting and by banks and people who lend money. It is calculated by using a set percentage, generally pre-determined or decided by the party that is lending the money.
  • The borrowed money is called Principal Amount. When we borrow and then pay back, we pay back the Principal Amount plus the additional Interest Amount, which has been calculated.
  • The person borrowing the money is called a Borrower.
  • The person giving the money is called a Lender.
  • Interest is calculated as either Simple Interest or Compound Interest. And all banks or people who loan money use this.

What is simple interest?

Simple Interest is rate of interest calculated only on the principal amount, or on that portion of the principal amount that remains. It excludes the effect of compounding. Simple interest can be applied over a time period other than a year, for example every month or week, even every day.

Simple interest formula –

Simple Interest =

P x R x T

  • P is the Principal Amount
  • R is the Rate of Interest
  • T is the Time

This type of interest usually applies to automobile loans or short-term loans, although some mortgages use this calculation method.

What is compound interest?

Compound Interest is the addition of interest to the principal amount of a loan or deposit, or in other words, interest on interest. It is the result of re-investing interest, rather than paying it out, so that interest in the next period is then earned on the principal sum plus previously-accumulated interest. Compound Interest is standard in finance and economics.

Compound interest formula –

Compound Interest (A) = P(1 + R/n)nT

A = the future value of the investment/loan, including interest
P = the principal investment amount (the initial deposit or loan amount)
R = the annual interest rate (decimal)
n = the number of times that interest is compounded per year
T= the number of years the money is invested or borrowed for

Have fun solving these simple interest exercises!

1. How much time will it take to yield Rs. 8892/- on Rs. 28,500/-, if the rate of interest is 7.8 percent?
Ans :

  • 2.5 years
  • 4 years
  • 2.3 years
  • 3 years

Correct Answer: 4 years
2. What is the amount of interest paid on Rs. 5432/- for 2.8 years, at 9 percent?

Ans :

  • Rs. 610/- per annum
  • Rs. 1030/- per annum
  • Rs. 1368/- per annum
  • Rs. 980/- per annum

Correct Answer: Rs. 1368/- per annum

Have fun solving these compound interest problems!

1. What is the time period if the calculated compound interest is Rs. 7299/- on a principal amount of Rs. 6285/-?

Ans :

  • 6 years
  • 3 years
  • 5 years
  • 4 years

Correct Answer: 3 years

2. What is the per annum percentage of compound interest calculated if the principal amount is Rs. 17,852 and the amount returned is Rs. 27938/- after 5 years.

Ans :

  • 5 %
  • 7%
  • 9%
  • 8%

Correct Answer: 3. 9%

Thomas Edison Biography

Early life

Thomas Alva Edison has been described as America’s greatest inventors. He was born on February 11, 1847, in Milan, Ohio and he grew up in Port Michigan. He was the youngest of seven children of Samuel and Nancy Edison. His father was an exiled political activist from Canada, while his mother was an accomplished school teacher and a major influence in Thomas’ early life.

An early bout with scarlet fever and ear infections left Thomas Edison with hearing difficulties and nearly deaf. He was a hyperactive child and so he attended school only for a few months and was instead taught by his mother.

The young entrepreneur

As a young child, he sold newspapers, candy and vegetables on the railroads. He even printed and sold his own newspaper, called the Grand Trunk Herald.

In 1866, at the age of 19, Thomas Edison moved to Louiseville, Kentucky, where, as an employee of Western Union, he worked the Associated Press bureau news wire. Edison worked the night shift, while he followed up on his two passions, reading and experimenting.

Wives and children

He married one of his employees, Mary Stilwell, and during their 13 year marriage, they had three children, Marion, Thomas and William, who also became an inventor. In 1884, Mary died at the age of 29 of a suspected brain tumour.

In 1886, Edison married Mina Miller, 19 years his junior. They also had three children, Madeleine, Charles and Theodore. Mina outlived Edison dying on 24th August, 1947.

Inventing years

One of the most prolific inventors of all time, Thomas Edison, created, and invented an impressive amount of objects we use in our everyday life. Apart from being an inventor, Edison also managed to become a successful manufacturer and businessman, marketing his inventions to the public.

His gift to early modern research were two huge laboratory facilities, Menlo Park and West Orange Laboratory, where some of his biggest and famous inventions were designed and discovered, including vacuum tube electronics. These became model of other research facilities.

At the time of his death on October 18, 1931, he had amassed a record 1093 patents covering innovations in telecommunications, electric power, sound recording, motion pictures, mining and cement technology.

Thomas Edison’s most famous inventions

His major contributions to the field of science and technology were the :

  1. Telegraph
  2. phonograph where Edison recorded ‘Mary had a Little Lamb!’
  3. first commercially incandescent electric bulb
  4. alkaline storage batteries and a kinetograph (a camera for motion pictures)
  5. including several research projects for the United States Government including submarines, ships and other equipments
  6. early stages of today’s wireless technology, known as the Edison Effect

5 Famous quotes by Thomas Edison

  1. Be courageous! Whatever setbacks America has encountered, it has always emerged as a stronger and more prosperous nation…Be brave as your fathers before you. Have faith and go forward.
  2. I never perfected an invention that I did not think about in terms of the service it might give others… I find out what the world needs, then I proceed to invent.
  3. When you have exhausted all possibilities, remember this: you haven’t.
  4. To have a great idea, have a lot of them.
  5. What you are will show in what you do.

What is an Exponent?

Definition of exponent

An Exponent is a number that states how many times the base number is to be used in multiplication. The Exponent Number appears on the top right of the base number as a small number.

Basic exponent rules

  • 55 means 5×5. The smaller number 2 is the Exponent and denotes the number of times 5 needs to be multiplied.
  • So instead of writing 2x2x2 we can simply write 23
  • The Exponent way is much shorter and easier to write an and comes in handy when you need to solve big equations. Exponents are also known as Index or Power.
  • Thus we can say that tells you to multiply ‘a’ by itself ‘n’ number of times.

Example: 35 = 3x3x3x3x3= 243

Properties of exponents

Suppose A = 1 or 0 exponent

  • If the Exponent is 1 then you have the number itself. Example: = 91 = 9
  • If the Exponent is 0 then you get 1. Example: 50 = 1
  • If both the Number and the Exponent is zero 00 then the result is indeterminate.

Negative Exponents

A Negative Exponent is just the opposite of Multiplication, that is Division.
So, 5-1
Is basically 1/52 = 1/25= 0.04
A negative exponent means how many times you need to divide 1 by the number.
Example: 6-3 = 1/= 0.0046

Grouping exponents with signs

In order to avoid confusions, use Parenthesis like () brackets.

There is a difference:

  • With brackets: (ab)2 = (ab)x(ab)
  • Without brackets: ab2 = axbxb


  • -22 = (-2)X(-2)= 4
  • -22 = -(2)2 = -4

Special exponents:

  • When a number has an Exponent of 2, it is called Squared.
  • When a number has an Exponent of 3, it is called Cubed.

Special cases:

Example : 52 x 53

  • Is same as 5 to the power of 2+3 or 52
  • So when the bases are same you can add the exponents during Multiplication.


  • This is the same as 3 to the power of 4×2 or 32
  • This is the case of exponent on top of an Exponent and here we multiply the Exponents.

Worksheet on exponents

1. Write the expression using exponents:
a) 56 x 56 x 56
b) 1.8×1.8×1.8×1.8×1.8×1.8
c) (-2)x(-2)x(-2)x(-2)

Ans: 563; 1.83; -24

2. Solve the following exponents:
a) 103
b) 04
c) 26
d) 18

Ans: 1000; 0; 64; 1

3. Solve the following equations:
a) -(1/2)5
b) -0.52
c) -1.23
d) -(5/2)3

Ans: 1/32;  0.25;  1.2;  125/8

4. Solve the equations:
a) 10-3
b) 3-2
c) 5-4
d) 1-1

Ans: 1/1000;  1/9;  1/625;  1

Types of Objects in English

What is a subject?

We all know about a subject in English grammar. A subject is a person, place, thing or an idea that the sentence is talking about. This subject performs an action which we know as the verb.


  • Mona played.
  • Ritu ate.
  • Here Mona and Ritu are subjects, while played and ate are the verbs or actions respectively.
  • Mona played with a doll.
  • Rita ate an apple.
  • Here, doll and apple are the objects.

What is an object?

An object is a person or a thing that receives the action of the verb. An object is a noun or a pronoun or a noun phrase that is affected by the action verb. It also completes a sentence.

Find the objects in these sentences:

  • The boys are playing with kites.
  • They are clicking pictures.
  • Ria is reading a book.

What are the different types of objects?

There are two types of objects – direct and indirect objects

What is a direct object?

A direct object answers the questions ‘what’ or ‘whom’. The noun object follows the transitive verb and completes the sentence.
Sam wrote a letter.
Here it answers the questions ‘what’ so letter is the object.


  • Pooh collected honey all day.
  • Here honey becomes the object.
  • Tim brought his friend to the cricket match.
  • Here it answers ‘whom’ so friend becomes the direct object.

What is an indirect object?

An indirect object answers the questions ‘to whom’, ‘for whom’, ‘to what’ and ‘for what’. Here the indirect object always comes before the verb and the direct object.


  • He bought his daughter a scooter.
  • It answers the question ‘for whom’ so ‘his daughter’ is the Indirect object.
  • Raju sent Mani a lovely postcard.
  • It answers the question ‘to whom’ so Mani is the Indirect object here.

Usage of direct objects in a paragraph

Shivali held her diary tightly. In the other hand she had a spatula. She wanted to hit the spider but could not find the courage.

Usage of indirect objects in a paragraph

Mr. Mehta opened his wallet and gave the shopkeeper the money. He had bought milk for his white cat. It was a cold night and he had to heat it for the cat.

What is Graham’s Law?

What is Graham’s Law of Diffusion and Effusion?

In1829, Thomas Graham, a Scottish Chemist formulated the Graham’s Law of the Diffusion and Effusion of Gases. According to this Law, the rate of Diffusion of different gases, at a constant temperature, is inversely proportional to the square root of its density.

Formula for Graham’s Law of Diffusion and Effusion

r ∝ 1/(M)½


r = rate of diffusion or effusion
M = molar mass

The Molar Mass tells you the number of grams per mole of a compound. The units for molar mass is grams/mole. It indicates the number of atoms, ions, molecules, or formula units present in a particular chemical.

3 Fun facts about Graham’s Law

  1. Our noses can smell because of Graham’s Law. Graham’s Law determines what we smell faster. Some gases travel faster and some gases travel slower.
  2. Respiration in all living things is based on Graham’s Law, including respiration through skin or lungs.
  3. You would have noticed balloons lose air from them slowly, even if they haven’t burst? This is because of Diffusion of Gases.

What is the Ideal or Universal Gas Law?

According to the Universal or Ideal Gas Law, the relationship between the pressure, volume, and temperature for a fixed mass (quantity) of gas is as follows:

  1. If temperature and pressure are kept constant, then the volume of the gas is directly proportional to the number of molecules of gas.
  2. If the temperature and volume remain constant, then the pressure of the gas changes directly proportional to the number of molecules of gas present.
  3. If the number of gas molecules and the temperature remain constant, then the pressure is inversely proportional to the volume.
  4. If the temperature changes and the number of gas molecules are kept constant, then either pressure or volume (or both) will change in direct proportion to the temperature.

Formula for the Universal or Ideal Gas Law

The formula for the Universal Gas or the Ideal Gas Law is :

PV = nRT


p is pressure
V is volume
n is the number of moles
R is the universal gas constant
T is temperature (K)

The Universal or Ideal Gas Law can be derived from the Kinetic Molecular Theory.

What is Kinetic Molecular Theory?

Kinetic Molecular Theory shows us how individual gas molecules behave or interact with one another.

According to the Kinetic Molecular Theory :

  1. Molecules are point masses (they have no volume)
  2. Gas molecules exert no force on each other unless they collide
  3. Collisions of molecules with each other or the walls of the container do not decrease the energy of the system
  4. The molecules of a gas are in constant and random motion
  5. The temperature of a gas depends on its average kinetic energy, that is, the energy of an ideal gas is entirely kinetic.

Elasticity vs Plasticity

All of you would have heard the terms ‘plastic’ and ‘elastic’. Do you know that ‘plastic’ and ‘elastic’ are also important scientific terms that are used to describe the properties of materials such as rubber, plastic, metal, etc?

What is elasticity?

In Physics, when an external force is applied to the surface of any material, the material goes through a physical change or deformation. When the force is removed, the material, depending on its properties, may or may not return to its original shape. Now, if the material returns to its original shape, it is said to be elastic in nature, and this property is known as ‘elasticity’.

What is plasticity?

On the other hand, if the material does not regain its original shape, it is said to be plastic in nature, and this property is known as ‘plasticity’.

What kind of materials are known as elastic and plastic materials?

Elastic material:

One of the most common examples of elasticity is a rubber band. You can easily stretch it to a length many times its original one, but when you release it, it returns to its original shape. The balloons that you use in your birthday parties are again made of rubber, which is an elastic material. Even those stretchable jeans and shirts that you wear are made of an elastic material, mostly spandex which is a stretchable fiber.

Plastic material:

The bending of a steel rod upon applying force is an example of plasticity. Once bent, it cannot come back to its original position.

What happens when force is applied to a body?

When an external force is applied to a body, the body tends to break. This happens because the distance between the atoms inside it, increases and each atom tries to pull its neighboring atom closer to itself. The pull between the atoms creates a force inside the body that tries to resist the deformation. This force is called strain, and the deforming force on the body is known as stress. The resistance of a material to elastic deformation or deflection is called stiffness. Also, there is a limit to the force which a body can resist without breaking. This limit is called the elastic limit of a body.

Difference between plasticity and elasticity





It is an irreversible process.

It is a reversible process.


Plastic materials are highly ductile in nature.

Elastic materials are less ductile in nature.

Shape and size

The shape and size of materials change permanently in this process.

The shape and size of materials does not change permanently




Hooke’s Law and elasticity

Hooke’s Law proposes that the amount of elongation of a spring is directly proportional to the force that is acting on it. Springs and every elastic material require an application of some force to stretch it. The force required to stretch an elastic material depends on the stiffness of the material, and is known as the ‘Young’s modulus’ or ‘elastic modulus.

In other words, Young’s modulus is a measure of the flexibility of a given material. With the help of Young’s modulus, engineers and scientists can calculate and understand the behavior of a material under load. For example, it can be used to foretell how much a wire will extend under tension, or to predict the load at which a thin column will give away under compression.

Young’s modulus is constant over a range of strains. Such materials are called linear. Examples of linear materials include Steel, Carbon Fiber and Glass.
Rubber is a non – linear material.

Uses of plasticity in the metal industry

The metal industry takes advantage of the plastic properties of materials by making them undergo some degree of permanent deformation without rupture or failure. Almost all materials including metals, plastics, soils, rocks and concrete undergo plastic deformations. Heat and pressure are commonly used to shape these materials into the desired form. This is done in a carefully controlled environment so that the objects do not beak apart. Metals like copper, silver, steel and gold have greater plastic deformation ranges. Materials like rubber, crystals and ceramics have the least plastic deformation ranges.

5 Interesting facts about elasticity

  1. A steel bar or wire can be extended only around 1 percent of its original length, while in case of rubberlike materials, we can get elastic extensions of up to 1,000 percent also.
  2. When force is applied on a given body, the bonds between the atoms inside it break leading to deformations. Elastic materials like rubber have long-chain molecules that uncoil because of which it gets extended and gets back into shape when they recoil.
  3. Rubber can be stretched three times its original size.
  4. Your hairs have elastic properties too. A single strand of hair can hold 100 grams of weight without breaking!!
  5. Young’s modulus is represented by the alphabet E. The higher this value is, the stiffer the material is!!

What is Charles’ Law?

Charles’ Law of Ideal Gases

Charles’ Law of Ideal gases is named after Jacques Charles, who formulated the original law.

An ideal gas maybe defined as a theoretical gas composed of molecules on which no forces act, except upon collision with one another and with the walls of the container in which the gas is enclosed.

It is a gas which perfectly follows Boyle’s Law.

Charles’ Law is a special case of the ideal gas law. It states that the volume of a fixed mass of a gas is directly proportional to the temperature. This law applies to ideal gases held at a constant pressure, where only the volume and temperature are allowed to change.

What is the formula for Charles’ Law?

V/T = k,

where V is the volume of gas, T is the temperature of gas (measured in kelvins) and k is a constant.

According to this formula, at a fixed pressure, the volume of a gas is proportional, to the temperature of the gas. As the temperature increases, the volume of the gas also increases.

6 Facts about Charles’ Law

  1. Jacques Charles, who formulated Charles’ Law of Ideal Gases, is also the inventor of the first hydrogen gas balloon, which made its first flight in August, 1783.
  2. On heating up a fixed mass of gas, that is, increasing the temperature, the volume also increases. Similarly, on cooling, the volume of the gas decreases.
  3. Air conditioners and Fans function using Charles’ Law. Hot air rises up and cold air comes down. Fans function on revolving the air, where as air conditioners also give off a blast of cold air from compressed coolants.
  4. Breads and cakes also use Charles’ Law of Ideal Gases. Carbon dioxide trapped in fermented dough, expands on baking and causes fluffy breads and cakes.
  5. If you keep aerosol and deodrant spray cans in sunlight, they can burst. Compressed gases will expand when the temperature inside the cans increases.
  6. Steam engines and car combustion engines also work on the principle that gases expand as temperatures increase. Charles Law is used to apply mechanical movements in these engines.

What is Boyle’s Law?

Definition of Boyle’s Law

Boyle’s Law is an experimental gas law that describes how the pressure of a gas tends to increase as the volume of the container decreases. It is named after the chemist and physicist Robert Boyle.

What does Boyle’s Law state?

According to this law : If a fixed amount of ideal gas is kept at a fixed temperature, the pressure (P) and volume (V) are inversely proportional, that is, when one doubles, the other is reduced by half.

What is an ideal gas?

An ideal gas maybe defined as a theoretical gas composed of molecules on which no forces act except upon collision with one another and with the walls of the container in which the gas is enclosed.
It is a gas which perfectly follows Boyle’s Law.

Why is Boyle’s Law important?

Boyle’s Law is important for us to understand how gases behave under pressure.
The practical uses of Boyle’s Law is seen all around us everyday.

Practical applications of Boyle’s Law

  1. Medical syringes use this principle. The plunger creates a space when it is pulled back and reduces the pressure in the tube. The fluid draws up inside the tube, because of this low pressure inside, balancing the pressure inside to pressure outside.
  2. When you climb high altitudes or are in an aeroplane, your ears ‘pop’ or you feel uncomfortable because of a change of pressure in your head. This is because the pressure inside the body is not in balance with the pressure outside which is lower at high altitudes. This is against Boyle’s Law. So your body has to undergo a period of acclimatisation.
  3. Deodrants and other spray cans work on Boyle’s Law. The compressed air, which is in the can, is a liquid because its boiling temperature is lower than room temperature. This gets released as the nozzle is pressed. Once the seal is released, the liquid inside the container expands and becomes a gas. So you get a whiff of your favourite smell, or a coat of paint.
  4. Popular aerated drinks and sodas also use Boyle’s Law. Carbon di oxide gas is mixed with syrups and water to make soft drinks. Mixing Carbon di oxide increases the pressure in the liquid making it fizzy, which is what aerated drinks are about!
  5. Deep sea diving also uses an understanding of Boyle’s Law to acclimatise deep sea divers.
    When deep sea divers go under water, after a certain point, while the pressure in their body is still at sea level, the pressure at deep sea level is high. As the divers descend, pressure inside the body increases along with the fact that they are breathing in compressed air from air tanks. When the divers start their ascent, they have to decompress at different levels to release the pressure and the mixed gases inside them. The different pressures inside and outside, plus the the fact that compressed air starts expanding as the ascent begins can cause air bubbles in between tissues and cells, which can cause severe damage, even death.

Fluid Mechanics Fundamentals

What is fluid mechanics?

In science, fluids refers to any substance that takes on the shape of its container or continously deforms.

Fluid mechanics is the study of gases and liquids at rest and in motion. This area of physics is divided into fluid statics – the study of the behavior of fluids at rest, and fluid dynamics – the study of moving fluids. Fluid dynamics is further divided into hydrodynamics or the study of water flow, and aerodynamics or the study of airflow.

Most problems in the field of fluid dynamics are too complex to be solved just by mathematical calculations. Such problems are solved by numeric methods using computer simulations. This branch of study is called numerical or computational fluid dynamics (CFD).

Real life applications of fluid mechanics

Understanding how fluids behave helps us in understanding the mechanism of flight and water currents. For example, fluid mechanics can be used to understand how aircrafts fly through the air, how ships sail through water and also changes in the weather patterns.

Main principles of fluid dynamics

  • Fluids are the substances that flow when an external force is applied to them.
  • Liquids and gases are both fluids.
  • Fluids do not have a definite shape and they conform to the shape of containers they are poured in.
  • The total force exerted by a liquid at rest on a given surface is called thrust.
  • The SI unit of thrust is newton.
  • A faster, moving fluid has less pressure than a slower, moving fluid.

Archimedes’ principle

If an object is immersed in a fluid, be it a balloon in air or a ship sailing in the ocean, it displaces the fluid, in which it is immersed. The amount of fluid displaced is equivalent to the weight of the object.

When a body is partially or fully immersed in a liquid, an upward force acts on it which is known as buoyancy.

Bernoulli’s principle

In 1738, a famous scientist called Daniel Bernoulli introduced the world to an interesting and important scientific theory. According to it, a fluid moving at a higher speed has lower pressure than a fluid moving at a lower speed. We can use Bernoulli’s principle to measure the speed of a liquid or gas moving in a pipe or over a given surface.

This principle also explains how aircrafts are able to take off from the ground. Because the wing of an aircraft is flat at the bottom and curved on the top, the air has to travel a greater distance along the top surface than along the bottom surface. To do this, air has to go faster over the top, causing its pressure to decrease. This makes a higher-pressure air pocket at the bottom of the aircraft which gives it a lift and makes it airborne.

What is fluid flow?

A fluid in motion is called a flow. It includes a wide range of fluid movement through the air, through a pipe or a channel, or just along a given surface. The flow of a fluid is classified into different types based on the properties of the flow.

Steady vs. Unsteady flow

  • Steady flow – If the movement of a fluid does not change over time, it is termed as a steady flow.
    For example : Water flow out of a tap. Though the flow is unsteady to start with, but with time it becomes steady.
  • Unsteady flow – If the movement of a fluid keeps changing with respect to time, then it is called an unsteady flow.

Different types of fluid flow

  • Laminar flow – A smooth flow of liquid is said to have a laminar flow.
  • Turbulent flow – An unsteady, irregular and chaotic flow is called turbulent flow. This type of flow may contain eddies and vortices etc.
  • Pipe flow – Such type of flow is in contact with rigid boundaries on all sides. One example would be water moving through a pipe or air moving through an air duct.
  • Open-S channel flow – It is a type of flow where there is a minimum of one free surface, not in contact with a rigid boundary. For example – water moving through a river, rain water on the streets, and irrigation canals.

3 Interesting facts about fluid dynamics

  1. Archimedes discovered hydrostatics in about 250 BC. According to a legend, he rushed out of his bath and ran through the streets of Syracuse shouting ‘Eureka!’
  2. It is believed that Bernoulli started studying fluids because he was interested in studying the pressure and flow of blood in the human body.
  3. Most of the universe is made of fluids, including our atmosphere and oceans, planets such as Jupiter, and stars like the Sun as well. Even rocks and metals can become fluid upon heating.

The White Revolution in India

What is White Revolution?

White Revolution was one of the biggest dairy development movements, by the Indian Government, in India in 1970. It was a step taken by the Indian Government to develop and help the dairy industry sustain itself economically by developing a co-operative, while providing employment to the poor farmers.

The White Revolution helped increase milk productivity and milk was now sold at competitive market prices. This program increased the demand for development and production of healthy animals, use of modern technology in milk production sector and networking between various small and large scale dairy industries.

The White Revolution followed after the success of the Green Revolution and the aim of White Revolution was to make India one of the largest milk producers in the world.

How did the White Revolution start?

The White Revolution, known as Operation Flood, was launched in 1970. It was an initiative by India’s National Dairy Development Board (NDDB) and was the world’s biggest dairy development programme. It transformed India from a milk deficient nation into the world’s largest milk producers.

Operation Flood was based on the experimental pattern set up by Verghese Kurien, chairman and founder of AMUL, who was named the Chairman of NDDB and was also recognised as the architect of Operation Flood.

Under Verghese Kurien, the programme created national milk grid linking producers throughout India with consumers in over 700 towns and cities, reducing seasonal and regional price variations and ensuring that the milk producers get a major share of the income generated from end consumers, by forming co-operatives.

Father of the White Revolution

Verghese Kurien was the father of the White Revolution. He founded Amul, one of the largest milk producing companies in India. Kurien, along with his friend H. M. Dalaya invented the process of making milk powder and condensed milk from buffalo milk. Many companies were started under his leadership and former Prime Miniter Lal Bahadur Shastri created the National Dairy Development Board based on Amul’s management, resource and infrastructure arrangements.

What were the phases of the White Revolution in India?

Phase 1: This phase started in July 1970 with the objective of setting up dairy cooperatives in 18 milk sheds in 10 states. They were to be linked with the four best metropolitan markets. By the end of this phase in 1981 there were 13,000 village dairy cooperatives covering 15,000 farmers.

Phase 2: It aimed at building on the designs of phase 1 and on the assisted Dairy development programmes in Karnataka, Rajasthan and Madhya Pradesh. By the end of this phase in 1985 there were 136 milk sheds, 34,500 village dairy cooperatives and over 36 lakh members.

Phase 3: This phase emphasised on consolidating the gains of the earlier two phases by improving the productivity and efficiency of the dairy sectors for long term sustainability. It ended in 1996 and by that time there were 73,300 dairy cooperatives and over 9.4 million farmer members.

4 Advantages of White Revolution

  1. It ended the imports of milk solids in India and India started exporting milk powder to many foreign nations.
  2. Dairy industries and infrastructures modernised and expanded. Around 10 million farmers earn their income from dairy farming.
  3. Dairy needs are met locally.
  4. Genetic improvement of milking animals has increased due to cross breeding.

Hydrogen Fun Facts

9 Facts about hydrogen you should know!

  1. Hydrogen was distinctly recognised as an element in 1766 by the English physicist and chemist Henry Cavendish. The element was named hydrogen by the French chemist Antoine Lavoisier.
  2. The name hydrogen comes from the Greek words, Hydro meaning ‘water’, and gene, meaning ‘forming’.
  3. Hydrogen is an essential element of our world. Infact it makes up 75% of the mass of the universe. It is found in the sun and all stars. Hydrogen is believed to be one the element produced in the Big Bang, the start of the universe as we know it today. And is the source of energy of all the stars, even the energy we get from the sun.
  4. Hydrogen is the simplest and lightest element on the periodic table of elements. And bonds to itself or to something else to fill its outer shell. It forms both negative and positive ions. That is why it is represented as H2. Its atomic weight is 1.00797 making it the lightest of all elements.
  5. Hydrogen is odourless, colourless and tasteless. And is undetectable by human senses.
  6. Hydrogen is highly flammable but will not ignite unless an oxidiser (air) and ignition sources are present.
  7. Hydrogen fuel cells make electricity. They are very efficient, but expensive to build though. Small fuel cells can power cars. Power generated by hydrogen is environmental friendly as it reduces dependency on fossil fuels and the by product is water. But the production of hydrogen as fuel is not eco – friendly or cheap!
  8. Hydrogen is the main component of Jupiter and the other gas giant planets.
  9. The first gas balloon flight in Paris in 1783 used hydrogen.

What are the main uses of hydrogen?

  • Hydrogen is used to make ammonia for fertilizer, in a process called the Haber process, in which it is reacted with nitrogen.
  • The element is also added to fats and oils, such as peanut oil, through a process called hydrogenation.
  • Hydrogen use include rocket fuel, welding, producing hydrochloric acid, reducing metallic ores and filling balloons.

Hormones in Animals

What are hormones?

Hormones are specific molecules produced by the endocrine system, that act as messengers to perform important and critical functions of the body. They are directly released by the endocrine glands (without ducts) within the body into the circulatory system and reach the organs or areas of the body that require attention. The word hormones is derived from the greek word ‘to set in motion’.

They regulate specific biological activities including growth, development of the body skeleton, muscles, metabolism, movements, water usage and storage, electrolyte balance, and sexual development including physical appearance.

Both plants and animals have hormones to carry out important functions. In plants the hormones are called phytohormones and endogenous growth inhibitors. A combination of these determine normal growth process in plants.

3 Types of hormones in animals

Animals have three types of hormones based on their chemical composition and origin. They are :

  1. Steroid Hormones
  2. Peptide Hormones
  3. Amine Hormones

What is an endocrine system?

An endocrine system maybe defined as a set of glands that secrete hormones directly into the blood. As the body’s chemical messengers, hormones transfer information and instructions from one set of cells to another.

Do hormones act only on the part of the body they are meant for?

Yes, although the organism’s body has several hormones in the blood at any given time, the designated hormones affect the cells that are genetically programmed to receive and respond to its message because hormones are target specific.

Hormone levels in the body are affected by factors such as stress, infections and changes in the balance of fluids and minerals in blood.

What are the different endocrine glands in animals?

1. Pineal Gland :

The pineal gland is located near the centre of the brain, dorsal to the diencephalon and produces the hormone Melatonin, which affects reproductive development, sleeping patterns and seasonal functions.

2. The Pituitary Gland :

It is a pea shaped gland located at the base of the brain and is considered to be the master gland and secretes several hormones like Growth Hormone, TSH, LSH, ACTH, MSH, Vasopressin and Oxytocin.

3. Hypothalamus :

It is a neuro – endocrine part of the brain and links the nervous system and the endocrine system through the pituitary gland. It secretes hormones like TRH, GnRH, GHRH, CRH, Somatostatin and Dopamine.

4. The Thyroid Gland :

It is located in the neck, ventral to the larynx and is one of the largest glands. It produces three very important hormones, Triiodothyronine, Thyroxine and Calcitonin. The hormones released are important for metabolism and a healthy skeletal structure.

5. The Parathyroid Glands :

These are two pairs of small, oval shaped glands embedded on the dorsal surface of the thyroid gland present in the neck. They secrete Parathormone, which helps in regulation of Calcium and Phosphate ions in the bones and blood.

6. The Thymus Gland :

It is located in front of the heart, in the upper part of the sternum. It produces the hormone Thymosine which helps in the maturation of T – lymphocytes.

7. The Adrenal Gland :

The adrenal glands are located above the kidneys and hence are called as suprarenal glands.
There are two regions in the adrenal glands :

  • Adrenal Cortex – it secretes hormones like Cortisol, Aldosterone and Androgens.
  • Adrenal Medulla – it secretes hormones like Adrenaline and Noradrenaline. Adrenaline is also called the fight or flight hormone and is released when the body faces stressful situations involving danger, anger and excitement.

8 The Pancreas :

It is located just below the stomach within the curve of the intial part of the small intestine, the duodenum. It is both exocrine (with ducts) and endocrine in function. It secretes Insulin, Glucagon, Somatostatin and Pancreatic polypeptide. They are important for maintaining metabolism. Insulin controls blood sugar levels.

9 The Gonads :

There are two types of gonads. One for the female species and one for the male species.

A. The Ovaries : They are the female sex organs and lie on either side of the female abdominal cavity. Ovaries produce the female hormones Oestrogen/Estrogen and Progesterone.

  • Oestrogen/Estrogen – It controls changes at female puberty, like the feminine voice, soft skin, and development in mammary glands.
  • Progesterone – It controls uterine changes in the menstrual cycle and helps maintain pregnancy.

B. The Testes : A pair of testes make the male sex organs and are located in the scrotum, outside the male body. Testes produce the male hormone, Testosterone. Testosterone controls changes in the male body at puberty, like a deeper voice, development of penis, facial and body hair.

Lines and Angles

What is a straight line?

All of you have drawn different types of lines while making paintings, playing paper games and doing your homework. But, do you know what exactly a line in terms of Geometry is?

A line is a straight, thin, zero-width object that extends on both sides and has no curves. Here are some examples of straight lines-

Properties of straight lines

  • A straight line travels on a straight path which can be extended indefinitely in both the directions.
  • A straight line is shown by two arrowheads in opposite directions.
  • A straight line does not have any fixed length.
  • A straight line has no beginning point or end point.
  • A straight line may have infinite number of points on it.
  • A straight line is often denoted by small letters of the English alphabet.

What is a line segment?

A line segment is a straight path which has a definite length with two endpoints. It is a part of the line.

7 Types of straight lines

  1. Vertical straight lines: Vertical straight lines go up and down.
  2. Horizontal straight lines: Horizontal straight lines go from left to right or vice versa.
  3. Perpendicular lines: Perpendicular lines are straight lines that intersect or cross each other at right angles.
  4. Oblique or slanting lines: Oblique or slanting lines are straight lines that slant and make a slope.
  5. Transversal lines: Transversal lines are the lines that intersect two or more other lines.
  6. Intersecting lines: Intersecting lines are the lines that cross other lines.
  7. Parallel lines: Parallel lines are the straight lines that never intersect or cross one another.

What is a ray?

A ray has one end point and infinitely extends in one direction. The Sun’s rays are the perfect examples of rays.

What is an angle?

An angle is the figure formed by two rays, called the sides of the angle, sharing a common endpoint, called the vertex of the angle.

10 Types of angles

  1. Acute angle: The angle that is between 0° and 90° is an Acute angle.
  2. Obtuse angle: The angle that is between 90° and 180° is an Obtuse angle.
  3. Right angle: The angle that is 90° is a Right angle.
  4. Straight angle: The angle that is 180° is a Straight angle.
  5. Reflex angle: The angle that is greater than 180 degrees.
  6. Supplementary angles: If the sum of two angles is 180° then the angles are called supplementary angles.
  7. Complementary angles: If the sum of two angles is 90° then the two angles are called complementary angles.
  8. Adjacent angles: The angles that have a common arm and a common vertex are called adjacent angles.
  9. Linear pair: The pair of adjacent angles whose sum is a straight angle is called a linear pair.
  10. Vertically opposite angles: When two lines intersect, the angles formed opposite to each other at the point of intersection (vertex) are called vertically opposite angles.

What is a curved line?

A curved line is a line that has a curve or arc. Curved lines are not straight lines. Here are some examples of curved lines –

7 Interesting facts about lines and angles

  1. Parallel lines are used in everyday structures that we see around us such as buildings, roads and footpaths.
  2. The sum of all angles in a Triangle is 180º.
  3. Adding up all angles in a 4 sided shape such as square/rectangle, parallelogram or quadrilateral is 360º.
  4. A right angle is denoted by a square mark.
  5. The word angle is derived from a Latin word ‘angulus’ meaning corner.
  6. The word ‘acute’ means sharp. The word obtuse means blunt.
  7. A complete angle or a full angle is known as ‘perigon’. It has 360 degrees or a complete one turn.

Difference between a star, planet and moon

Our solar neighborhood is really an exciting place. It is full of different heavenly bodies such as planets, moons, asteroids, meteors, comets, and many other exciting objects. Let us learn more about them.

What is a planet?

Planets are large natural objects that orbit, or revolve around, stars. You are standing on one at this moment! Yes, Earth is a planet too. Today, we have eight planets orbit the star called the Sun. In order, from the closest to the Sun, these planets are Mercury, Venus, Earth, Mars, Jupiter, Saturn, Uranus, and Neptune.

While some of the planets are small, rocky bodies with a solid ground – Mercury, Venus, Earth and Mars; the others are big gas giants – Jupiter, Saturn, Uranus, and Neptune.

Earlier, the scientists were of the opinion that there are nine planets including Pluto, but in 2006, modern scientists came up with three compulsory conditions to award planet – hood to any heavenly body :

  • A planet must revolve around the Sun
  • Be spherical in shape
  • Its orbit must be free of other small objects

Unfortunately, Pluto failed to meet the third condition and had to step down from being a planet to a “dwarf planet”.
So far, hundreds of worlds beyond our solar system have been discovered and many new ones are in the process of being discovered. Scientists believe some of these planets may sustain alien life. Well, no one knows for sure, but there is a high probability that an alien kid elsewhere in the galaxy is also reading about us and the Earth in an article like this!

What is a star?

Stars are giant spheres of superhot gas, generally made up of hydrogen and helium. Stars get so hot and bright because of a process called nuclear fusion that takes place inside them. Nuclear fusion is a process in which hydrogen gas gets converted into helium, releasing light and heat. Though it seems to us that the stars twinkle in the night, they really don’t. What happens is that the light of the stars has to travel through various layers of our atmosphere during which it bounces around, and we feel that the stars are twinkling.

What is a moon?

Moons are natural objects that orbit planets. There are about 170 moons in our Solar System that revolve around different planets. Our Moon was probably made billions of years ago when a large object hit the Earth. Many small rocks were thrown out by the explosion and they started revolving around the Earth. With the due course of time, they got fused together, cooled down and became the Moon.

How is a planet different from a star?

What are the characteristics of a star?

  • A star has its own light.
  • Stars do not undergo any noticeable change in their position.
  • All stars have very high temperatures.
  • There are billions of stars in the galaxy.

What are the defining characteristics of a planet?

  • A planet has no light of its own. It shines by reflecting the light of the sun.
  • Planets do not twinkle.
  • Planets move around the stars and there is a noticeable shift in their position in the sky.
  • Planets have low temperatures.
  • There are only nine planets in the solar system.
  • Similarities between stars and planets
  • Planets and stars both orbit other stars. This is a similarity between the two heavenly objects.

Difference between a moon and a planet

If an object revolves around the Sun, it is called a planet; however, if it circles some other heavenly body (generally a planet) other than the Sun, it is called a moon.

Are stars planets or suns?

A star is called a “sun” if it is the center of a planetary system. There is a fair chance of having a large percentage of the stars in the galaxy that have planets orbiting them. You can call all of them “suns”.

What is the Sun?

The Sun is one of the million stars that are present in our galaxy. It is placed at the center of our solar system. It is a huge ball of gases with millions of degrees of heat. Because of its large size, it has a strong gravitational pull which helps in keeping the Earth and the other planets in line. Without the gravitational pull of the Sun, all planets would go spinning off into space.
Without the Sun, there would be no life on Earth and it would be frozen solid. The Sun is also responsible for change in seasons, as the Earth travels around the Sun, on its orbit.

9 Interesting facts about stars, planets and moons

  1. The Sun’s light reaches the Earth in eight minutes. This is known as the speed of light.
  2. Water was discovered on the moon in November 2009
  3. The footprints of Apollo astronauts are still visible on the Moon. They will remain visible for at least 10 million years more as there is no atmosphere or wind-erosion on the Moon.
  4. Scientists usually refer to moons in the galaxy as planetary satellites. On the other hand, human-made satellites are called artificial moons.
  5. You can see about 7,000 stars with naked eyes from Earth.
  6. Many stars and constellations are named after ancient gods and animals that they resemble.
  7. Every star you see in the sky is larger and brighter than the Sun.
  8. The largest planet in the solar system is Jupiter and Mercury is the smallest.
  9. Neptune is the coldest planet and Jupiter is the hottest planet.

What are seedless plants?

All of us have read in our Science classes that plants grow from seeds. This is not true of all the plants that are found on Earth. Yes, you would be surprised to know that there are many plants that do not grow from the seeds.

Evolution of seedless plants

Scientists believe that the seedless plants first appeared on Earth about 400 million years ago. Such seedless plants include ferns, mosses, horsetails and liverworts. These plants have stems, roots, and leaves like other plants, but since they do not produce flowers, they have no seeds.

These plants, however, have specialized tissues for conducting water and food. Seedless plants lack a system of retaining and transporting water.

Reproduction in seedless plants

Now the question is, how do the seedless plants reproduce? Well, the seedless plants reproduce via seed-like objects, known as spores, or they produce through asexual reproduction.

What are spores?

Spores are usually unicellular or single-celled structures, having only one set of chromosomes. Spores lay dormant until conditions are favorable. Once conditions are favorable, cell division takes place in them and they grow into full-fledged plants. Spores are produced in bulk in a seedless plant and since they are very small and light, they are dispersed by the wind to new areas where they can grow.

What is asexual reproduction in seedless plants?

Some seedless plants reproduce asexually. This method of reproduction occurs when a part of the plant falls off on the ground and grows into a new plant on its own.

What are vascular and non-vascular plants?

Vascular plants are the plants which have a series of tubes that can transport water. All seed plants are vascular, whereas seedless plants can be vascular or non-vascular. Seedless vascular plants include ferns and horsetails. Such plants have proper roots, stems, and leaves. Non-vascular plants include mosses, liverworts, and hornworts. These plants do not have well-differentiated root, shoots and stems or water transport system so they thrive only in moist places.

Examples of seedless vascular plants

A. Fern

Ferns are one of the most common plants found in our homes. You would have seen these plants at the florist and even being used for landscaping in big hotels, malls and airports. Ferns produce spores on the underside of their leaves. The leaves of ferns are called fronds and have small brown spots down below. These small brown spots are nothing else but spores and you can feel them with your hands too. It is believed that the ferns were the first plant species to develop a water transportation system that helped them in growing larger.

B. Horsetails

Horsetails and ferns are closest living relatives to seed plants, because they have a vascular system. Most of these plants are extinct so the chances of you seeing them are rare.

Examples of non-vascular seedless plants

A. Mosses

Mosses are small, soft and spongy plants that grow only a few inches tall. They grow in clumps and form a sort of a carpet on the ground. Mosses anchor themselves to rocks and soil with short growths called rhizoids.

B. Liverworts

The worts are considered to be the simplest of all plants and believed to be one of the first plants to have colonized the Earth. They are small, flat and along the ground in large leaf-like structures. Instead of roots, they have little hair called rhizoids to absorb moisture. Like mosses, they also thrive in moist areas, and some species even spend their whole lives in water.

6 Interesting facts about the seedless plants

  1. In a hostile environment, such as the tundra where the soil remains frozen for almost the whole year, mosses provide food and shelter to many species, from small insects to musk oxen and reindeer.
  2. Mosses absorb pollutants from the air and hence the level of pollution at a particular place can be determined by the existing number of mosses there.
  3. Dried peat moss is a renewable resource for energy.
  4. Ferns promote the weathering of rock and help in soil formation.
  5. Ferns harbor nitrogen fixing bacteria in their roots and thereby enrich the soil in nutrients.
  6. Coal is primarily made of seedless vascular plants.

What is an Equation?

Definition of equation

An equation is a statement that says that the value of two mathematical expressions is equal. In simple words, an equation says that two things are equal. It is denoted by the equal to sign ‘=’.

Example of an Equation: 8+2= 12-2
The above equation says that the left side of the equation is equal to the right side. Thus an equation is a statement that states ‘this equals that’.

Different types of equations in mathematics

Students may come across these different types of equations in Math, Algebra to be specific:

1. Linear equations

Linear means having one line. These are equations of the type Y= ax+b where ‘a’ and ‘b’ are numbers and ‘x’ cannot be zero. In these equations ‘x’ has no exponents. Y=4x+3 is a linear equation.

2. Quadratic equations

This is a second degree equation where one variable out of all contains the exponent of 2. ax2+bx+c= 0 is a quadratic equation where x is not equal to zero.

3. Radical equations

These are equations whose maximum exponent on the variable is ½ and have more than one term. Here the variable is lying inside a radical symbol usually in a square root. √x+10=26 is a radical equation.

4. Trigonometric equations

These are equations in which the variables are affected by trigonometric functions. Cos 2x= 1+Sin 4x is a trigonometric equation.

5. Polynomial equations

A polynomial equation is one which takes away the highest exponent limit. Here all the ‘x’s are numbers and the equation consists of several terms. (x7 + 2×4 – 5) * 3x=0

6. Exponential equations

These are equations that have variables in place of exponents. ab = 0 is an exponential equation.

Solution of an equation

(x + 1)2 = x2 – 2
We need to first expand the variables on the left hand side of the equation with the formula of (a+b) 2= a2+ 2ab+ b2
X2+ 2x+ 1= x2-2
Now, x2 from both sides gets cancelled so we are left with
2x+1= -2
2x= -3
X= -3/2
X= -1.5

Solve the following equations

1. 4+n= 6
a. 4  b. 2  c.10  d. 0

2. 4*7= v+9
a. 28  b. 9  c. 19  d. -19

3. m/10= 9*6
a. 5.4  b. 540  c.64  d. -5.4

4. 10*11= x-3
a. 110  b. -113  c. 113  d. 107

5. (-5-v)/3=1
a. -8  b. 8  c. 1.67  d. 15

6. 7= w-(-7)/5
a. 56  b. 5.6  c. 35  d. 3.5

7. 2p-6=8+5(p+9)
a. 19.6  b. -19.6  c. 59  d. -59

8. 8(x+4)-4= 4x-1
a. -7.25  b. 29  c. 7.25  d. 32

9. 8(t+5)+2= 4.8t+4
a. 1187  b.11.87  c. 11.78  d. -11.87

10. (3v/3) – 3v= -5
a. -2.5  b. 2.5  c. -6  c. 15

How is gold formed?

What is gold?

Gold is a chemical element with the symbol Au (Latin : Aurum) and atomic number 79. It is one of the precious metals, known to man. In its purest form, Gold is considered a noble metal and is a slightly, reddish yellow, dense, soft, malleable and ductile metal.

It is one of the least reactive elements and occurs in its native, free, elemental state as nuggets or grains, in rocks, in veins and in alluvial deposits. Sometimes it is found mixed with other elements as gold compounds.

How is gold processed?

Gold was one of the first precious metals to be mined because it commonly occurs in its original state. It is a scarce metal and it is concentrated by geological processes to form commercial deposits of two principal types : lode (primary) deposits and placer (secondary) deposits.

Lode Mining

Lode deposits are the targets for gold prospectors seeking gold at the site of its deposit from mineral solutions. Gold is collected in a precipitate form and further purified. in lode mining, ores of gold are collected from the source by quarrying rocks with the ore deposits. This is known as the mother lode, geology.
A mother lode is the principal vein or zone of veins of gold or silver, found in rocks.

Placer Mining

Placer mining is the mining of water stream bed deposits. It is also done by open pit or open cast mining or other surface excavation processes. Gold in ancient times, before modern, sophisticated equipment was developed, was sourced through placer mining.

In olden times, river beds were panned for gold bits, carried along with eroded rocks by the force of gushing water streams from underground water sources.

Why is gold considered a precious metal?

  • A precious metal is a rare, naturally occurring metal of high economic value due to its extremely stable nature under harsh condition, natural or man made.
  • In ancient days, gold was used by nobility and various historical artifacts have been discovered made of gold from archaeological sites. It was used as currency by early civilisations, infact it is still used in international trading. The reason being so, grading the quality of gold doesn’t change over the years.
  • It is so malleable, that a single gram can be beaten into a sheet of one square meter and further till it is semi transparent.

5 Interesting facts about gold

  1. Gold is edible. Gold dust and gold foil are used in gourmet cuisine.
  2. Our bodies contain a small percentage of gold.
  3. More gold is recoverable from a ton of personal computers than from 17 tonnes of gold ore.
  4. Nearly all the gold on earth came from meteorites that bombarded the planet millions of years ago.
  5. The world’s largest gold nugget was called ‘Welcome Stranger’. It was found in Victoria, Australia in 1869 and weighed over 71 kg of which 65 kg became refined or pure gold.

What is a drought?

Almost everyone loves rains. We keenly wait for the rainy season to come after the summers. In many parts of our country, people do special rituals and prayers to bring about the rains in their respective areas. Drought is a type of natural calamity that occurs when an area gets less than its normal amount of rain over months or even years.

What causes a drought?

Just take out some time and think about how much water you use in a day. You drink water and use it to take a shower, brush your teeth and clean various items at home. Now can you imagine going without water for a week or longer? Well, that is exactly what happens during the droughts. There occurs a severe dearth of water in the areas that are hit by a drought.
The distribution of all the water on the earth’s surface is not even. While some places have lots of fresh water available in form of lakes and rivers, there are areas that have hardly any water. This is the reason droughts have been occurring for several hundreds of years, and still, keep occurring in different parts of the world.

4 Types of drought

  1. Meteorological drought : Meteorological drought is caused by the lack of rains and dry weather is the main factor for this type of natural calamity.
  2. Agricultural drought : Agricultural drought occurs due to the lack of moisture in the soil and affects crops.
  3. Hydrological drought : Hydrological droughts takes place when there is an acute shortage of surface water and ground water supply in a particular region, often as a result of less or no rains.
  4. Socio – economical drought : Socioeconomic drought occurs when the supply of some goods and services such as energy, food and drinking water become scarce because of a shortage of water and dry weather.

Effects of drought

Droughts have a drastic effect on all forms of life – be it animals, plants or humans. Since all living beings need water to survive, so an extreme drought causes them to die. Without water, humans are at risk of dying because of dehydration or hunger. Yes, hunger too because no water means no crops, and no crops mean no food supply. A severe shortage of both food and water is also known as famine. All of you know that India is predominantly an agricultural country. Agriculture in India is heavily dependent on climatic conditions. A favorable southwest summer monsoon is vital to get water for irrigating the Indian crops. In some parts of India, the failure of the monsoons results in water shortages and poor crop yields. This is especially true of the drought-prone regions such as Rajasthan, Maharashtra, Karnataka, Andhra Pradesh, Odisha, Gujrat, and Telangana. In the past, droughts have led to major Indian famines, including the Bengal famine of 1770, in which about one-third of the population died; the 1876 – 1877 famine, in which more than five million people died, the 1899 famine, in which over 4.5 million died and the recent drought in 1900 in India that resulted in the death of more than 5 million people. Millions of families have suffered not just in India, but all over the world because of droughts.

How can we prevent drought?

Water is a precious natural resource that is required for the survival of all living things on this planet, and so it is our duty to save it. We cannot prevent droughts from happening, but we can surely help in mitigating the impacts of drought by conserving water. If we use water wisely at all times, more water will be available to us and to other life forms when drought occurs. Every day we lose a lot of water doing simple everyday tasks. Did you know that by turning off the water while brushing your teeth and showering can save more than 100 liters of water in one month? We are sure that all of the wise children reading this article would have understood the importance of water in our lives and will take every necessary step to prevent its wastage.

3 Interesting facts about droughts

1. Droughts can cause dust bowls in certain areas which means that the top layer of soil gets completely blown away, leaving behind nutrient-deficient soil to sustain crop growth.

2. Droughts often result in wildfires as the vegetation becomes dry and more prone to catching fire.

3. While drought is mostly caused by irregular weather patterns, human activity can also be a cause of drought. Deforestation, farming, excessive irrigation, erosion, and climate change due to global warming are all human causes of drought

Plant hormones and their functions

What are plant hormones?

Plant hormones, also known as phytohormones are chemicals that regulate plant growth. The term, Phytohormone was coined by Kenneth Vivian Thimann, in 1948. In plants, these are produced by cells in one area of the plant, such as leaves, stems or roots and then transported to a different area of the plant in order for them to have a response.

How do plant hormones affect the plant?

Plant hormones shape the plant, affecting seed growth, time of flowering, the sex of flowers, senescence of leaves, and fruits. They affect which tissues grow upward and which grow downward, leaf formation and stem growth, fruit development and ripening, plant longevity, and even plant death. Hormones are vital to plant growth, and, lacking them, plants would be mostly a mass of undifferentiated cells. So they are also known as growth factors or growth hormones.

How do plants transport hormones within the body?

Plants lack glands that produce and secrete hormones. Instead, each cell is capable of producing hormones. Hormones are transported within the plant using localised movement and cytoplasmic streaming within cells and slow diffusion. Phloem and Xylem are vascular tissues that also help in the transportation of hormones from one part of the plant to another.

Types of plant hormones

Plant hormones can be classified into five major categories, some of which are made up of many different chemicals that can vary in structure from one plant to the next. The classifications is based on chemical structural similarities and their effects on plant physiology. Each class has positive as well as inhibitory function and work in tandem with each other, interplaying to affect growth regulation.

1. Abscisic acid

  • Abscisic acid, also called ABA and/or Dormin, is one of the most important plant growth regulators. It inhibits growth/germination of seeds. It is produced mainly in conditions that are unfavourable to plant growth. It induces seed and bud dormancy in winters.
  • As the temperatures change, the levels of Abscisic acid reduce/dissipate in plants to enable flowering in plants and trees and for germination of new seeds to occur. It also prevents seeds from germinating when still within a fruit.
  • In plants, during water stress, Abscisic acid, helps to close the stomata, to conserving water.

2. Auxins

  • Auxins were the first class of growth regulators discovered. They affect cell elongation by altering cell wall plasticity. They are responsible for stimulating the development of xylem (water transporting tissues throughout the plant) and inhibit growth of buds lower down the stems, ensuring the plant grows with the leading tip(apical dominance). They promote root growth and branching. In high doses, it however inhibits root growth and expansion.

3. Cytokinins

  • Cytokinins or CKs are a group of chemicals that influence cell division and shoot formation. They also delay senescence of tissues and are responsible for ensuring proper transport of the hormone auxin to where it is required in the plant’s body.
  • Cytokinins and auxins together have a synergistic effect with auxins and the ratios of these two groups of plant hormones affect major growth period in a plant’s lifetime. Cytokinins, in conjunction with ethylene promote abscission (fall or drop) of leaves and fruit.

4. Ethylene

  • Ethylene is also known as the ripening hormone. It is a gas that forms through the breakdown of methionine, which is in all cells. Its production increases when the seeds are mature, ensuring the fruit is released only when the seeds are ripe for germination.
  • Have you noticed how when you keep a ripe fruit with unripe ones, the unripe ones also ripen rapidly. This is because of ethylene.
  • Ethylene also affects cell shape and cell elongation. When, a growing shoot faces an obstacle, etheylene production increases and the stem becomes thicker, exerting more pressure to overcome the obstacle.

5. Gibberellins

  • Gibberellins were first discovered when the fungus, Gibberella fujikuroi, induced abnormal growth in rice plants.
  • Gibberellins or GAs include a large range of chemicals that are produced by plants and fungus. They are important for seed germination, initiating mobilisation of nutrients stored within the seed. Absorption of water by the seed causes the production of Gibberellins.

What is Economy? 

How many of you love playing Monopoly, Game of Life and Mine-craft? Well, these are not just any ordinary games; they are smart board games that teach you how economy works.

Where does the term economy come from?

The word economy comes from two Greek words- “household” and “manage.” Through the economy, goods and services in a particular region are produced in a way to produce profit.

Goods are physical objects that are bought and sold such as things like cars, clothes and food items.

Services are facilities provided by others for which we pay them. Services include things like teaching, healthcare, fire-fighting, and baby-sitting.

What is Economics?

The study of the economy is called Economics and a person who studies economics is called an Economist. A country is said to have good economy when the trade is flourishing and there are lots of good – paying jobs available for the citizens.

Economics has two branches – Macroeconomics and Microeconomics

What is Microeconomics?

Microeconomics is the branch of economics that tells us how people make decisions at a small scale. In microeconomics, we learn about the small – scale financial decisions. For example what and how much to buy from the store, or how many products a company should manufacture.

What is Macroeconomics?

Macroeconomics helps us to look at a bigger picture. It looks at the economy as a whole and while Microeconomics has to do with a individual or a company, Macroeconomics deals with a country or is global.

The study of macroeconomics includes the Gross National Product of a country, unemployment rates and its imports and exports etc.

Basic economic terms and concepts –

What is a Bank?

Bank is a financial institution that keeps our money safe. We can deposit and withdraw our money from the bank according to our convenience. Money that is in the account earns interest from the bank. That is, the bank pays the account holder a small fee.

What is Credit?

Credit is the ability to borrow money. For example, if we do not have enough money to buy something on our own, we can borrow money from the bank. This is known as bank-loan. People take bank-loans for buying cars, making houses and education of the children among other things. Bank-loan is a type of credit that the bank gives us. We have to return the loan to the bank along with an additional ‘fee’ that is known as the ‘interest’. Another type of credit is a credit card. If we have a credit card, we are allowed to borrow some amount of money from the respective credit card company or the bank through it for a particular period of time. We have to return that money to the credit card companies with a certain amount of, yes, you guessed it right- ‘interest’ later on. So, the next time you swipe the credit card of your parents for buying things, please remember, a bill with ‘interest’ would be coming soon. Use it prudently!

What is Debt?

Debt is the money that someone borrows from the other person, companies or the bank. It is an amount that is to be returned to the lender with or without interest.

What is Interest?

Interest is the fee that is charged for using someone else’s money.

What is Investment?

Investment is anything that is bought with the hope that it will generate income or become more valuable in the future. While some investments may result in a loss, some are sure to bring you profit. For example, a bar of gold will certainly be worth more in ten years from now.

What is a Mortgage?

Mortgage is a loan that we take against our personal belongings like gold or house from a bank or a finance company.

What is a Recession?

A drop in economic growth of a country and its business activities that lasts for more than 6 months is called recession.

What is Stock?

Stocks are sold by companies to raise money from the buyers. When we buy a stock in a company, we become owners of a small part of that company.

What is Stock Market?

Stock market is a place where stocks are bought and sold. A stock broker is a person whose job is to help us in buying and selling the stocks.

What is Taxes?

Taxes are the main way people pay for their government. Income taxes and sales taxes help the government pay for things like roads, schools, and the armed forces.

What is Unemployment?

The unemployment rate is the percentage of citizens who are out of work and looking for jobs. High unemployment rates are a sign of a weak economy.

What is GDP?

Gross Domestic Product, or GDP, is a measure used to check the health of a country’s economy. It is defined as the total value of all products manufactured and goods provided in a specific region during a specified period, usually, one year.

What is Inflation?

Inflation indicates a rise in the level of prices of basic commodities as compared to the money available. Ask your grandparents how much one pen cost when they were students like you. Compare it with the price of a pen today. You will get your answer.

Dear children, every time you make a financial transaction, you learn something about the economy. The best way to understand more about economy is to make wise use of your pocket-money by saving it and making a budget. This includes making a priority list of the things that you truly need. If you know how to use your money wisely right from the beginning, you will have absolutely no problem in comprehending the nuances of Economics as a subject later and become a wise spender of money.

Egypt Facts and Information

When we talk about Egypt, first few things that come to our mind are the humongous pyramids, mysterious tombs and mummies that had a curse put on them, all thanks to the Hollywood mummy-movies! Well, Egypt is much more than that.

The birth of Egyptian civilization

Egyptian civilization took birth some 8,000 years ago on the banks of the Nile when some hunters and fishermen settled there. The Egyptian people revered river Nile and believed it to be the source of their wealth.

They were quick learners and had mastered the art of irrigation to grow profitable crops which very soon made them extremely wealthy. Once, the money came, they started doing business with their neighbours and also learned to sail boats. Egypt was a flourishing land that rapidly attracted the attention of its enemies.

Brief history of rule in Egypt

First, it was taken over by its strong neighbours – the Romans and then it fell under the control of Muslim warriors. During the 16th century, Egypt became a part of the Ottoman Turkish Empire. In 1882, the British attacked and occupied Egypt. The Egyptians bravely struggled for their freedom, and in 1952, Egypt gained full independence from the British.

Current Egypt

Today, Egypt is a democratic country where elections are held to choose the leaders for running the country. The flag of Egypt is a tricolour consisting of the three equal horizontal bands of red, white, and black colour with a golden eagle placed in the centre of the white band. About 90 percent of Egyptians are Muslim and Arabic is the national language.

Egypt is famous for its delicious cuisine. The ancient Egyptians grew wheat and then made bread out of it. The fertile farmland nurtured by the Nile allowed them to grow a host of vegetables and fruits. The Egyptian food of today is a mixture of all the different civilizations that came to Egypt and left their influence in the due course of time. Modern Egyptian cuisine makes heavy use of legumes, veggies and fruits. Even after so many years, rice and bread remain staple foods. Molokhiyya, which is a spinach-like vegetable, and Ful mudammas or cooked beans, are still as popular as they were years ago.

Ancient Egyptian civilization

Egyptian people believed in life after death which is why they used to preserve the bodies of their dead so they could use them in the afterlife. The process of preserving dead bodies was known as mummification. It was a complicated and lengthy process in which various chemicals were applied onto the body and lasted up to 70 days or more.

Animals were very important to the ancient Egyptians. Cats were given utmost importance as they believed them to have magical powers.

Ancient Egyptian gods and goddesses

The ancient Egyptians worshipped a number of gods and goddesses that were part humans, part animals. Osiris was one of the most worshipped gods who ruled the underworld and judged the dead. Some job he had! His wife-goddess Isis was the mother of Horus, yet another Egyptian god.

One of the most famous gods was Thoth, who was regarded as the god of writing and science and the inventor of the hieroglyphics. An intelligent god indeed!

Mummies and tombs

Don’t you think? You would have also heard about Anubis in the Hollywood movies based on mummies. Anubis was a jackal-headed god, who was the considered as the god of mummies and tombs. We really wonder if he enjoyed the work that was assigned to him.

Tutankhamun or King Tut

The ancient Egyptian kings were known as ‘pharaohs’ who were thought to be both-a man and a god by the general public. Tutankhamun or “King Tut” is probably the most famous Egyptian pharaoh.

All the Egyptian pharaohs used to build magnificent pyramids for themselves and when they died, they were buried inside the pyramids along with the things that they cherished the most. It is believed that thousands of slaves were used to cut up large blocks of stone and then move them up the pyramid on ramps.

Egyptian pyramids

It took many years to build one pyramid so the pharaohs started building pyramids and tombs for themselves as soon as they took over command. The Pyramid of Khufu, also known as the Great Pyramid of Giza, is one of the Seven Wonders of the World. According to the scientists, it took at more than 20,000 workers over 23 years to erect the Great Pyramid of Giza. No wonder it is one of the best examples of man’s ingenuity!

The Sphinx of Giza

The Great Sphinx of Giza, a large half-human, half-lion Sphinx statue is on the west bank of the Nile River, next to the Great Pyramid. The Great Sphinx is one of the largest single-stone statues on Earth, and is commonly believed to have been built by ancient Egyptians in the 3rd millennium BC, somewhere between 2520 BC and 2494 BC.

7 Interesting facts about the Egyptians

  1. Though there were no smart phones to take selfies, looking beautiful was pretty important to the Egyptians. Men and women, both, wore lovely pieces of jewellery and make-up. While the rich wore jewellry made of gold and silver, the poor used copper. They loved using dark eye paints like green, blue and black. As far as clothes were concerned, Egyptians loved to wear white linen clothes to ward off heat. Men wore kilts and women wore long gowns.
  2. Women were given due respect in the Egyptian culture. They were allowed to hold high-ranking positions such as priestesses, administrators and supervisors.
  3. It is believed that the Egyptians invented writing. It made use of various pictorial symbols called Hieroglyphs. They used ink to write on a special kind of paper called papyrus.
  4. A pharaoh had to keep his hair covered all the time.
  5. The pharaohs were buried with their precious belongings in the pyramids which is why several traps and curses were put on the pyramids to try and keep robbers at bay.
  6. King Tut’s gold mask was made with 10 kgs of pure gold. Amazing, isn’t it?
  7. Bread was the staple food of the ancient Egyptians, but it was so hard that most of the Egyptians had severely damaged teeth.

Structure and Function of the Skin

What is skin?

Skin is the soft outer tissue covering vertebrates. It acts as a barrier and protection against water and fluid loss and prevents damage to internal organs and in some animals helps manage body temperatures as well. Other organisms, like arthropods, have other types of tissues that form their exterior, like an exoskeleton, which is made of chitin, or like in turtles and tortoise, an outer shell.

Different classifications of animals have different types of skin, like, fish, amphibians, reptiles and birds.

In mammals, the skin functions as the largest organ and performs various functions.

What is the mammalian skin made of?

The mammalian skin is composed of two primary layers – epidermis and dermis, with a basement membrane in between.

What is epidermis?

The epidermis is composed of the outermost layers of the skin. It forms a protective barrier over the body’s surface, responsible for maintaining fluids in the body and prevents pathogens from entering the body.

The epidermis contains no blood vessels and the cells in the deepest layers are nourished by diffusion from blood capillaries extending to the upper layers of the skin. The melanocytes present in the epidermis are responsible for producing melanin which gives the skin its colour.

What is basement membrane?

The epidermis and the second layer, dermis are separated by the basement membrane, which is a thin sheet of fibres. The basement membrane controls the traffic of cells and molecules between the two layers of the skin, through it’s complex structuring.

What is dermis?

The dermis is the layer of the skin beneath the epidermis and consists of connective tissue, cushioning the body against stress and strain. The dermis provides tensile strength and elasticity to the skin through a complex layering of extracellular matrix of collagen fibrils, microfibrils and elastic fibres embedded in layers of vital cellular fluids and molecules that help maintain the strength of skin.

The dermis is divided into two layers, the Papillary region and Reticular region.

1. Papillary region of dermis

This layer is composed of areolar connective tissue, and is named after the finger like projections called the papillae that extend toward the epidermis. The papillae increase the surface area of the dermis, providing extra strength.

2. Reticular region of dermis

The reticular region lies deep in the papillary region and is usually much thicker. It is composed of dense irregular connective tissue, and receives its name from the dense concentration of collagenous, elastic and reticular fibres that weave through it. These protein fibres give the dermis its properties of strength, extensibility and elasticity. Also located within the reticular region are the roots of the hair, sweat glands, sebaceous glands, receptors, nails and blood vessels.

4 Interesting facts on skin

  1. The skin renews itself completely in 28 days and sheds 30,000 to 40,000 dead cells per minute while it renews itself. An average human sheds 9 pounds of skin cells in a year.
  2. The human skin is home to a 1000 species of bacteria.
  3. The thickest skin in humans is found on the soles of the feet, where as the thinnest is found on the eye lids.
  4. On a hot day, the sweat glands can produce upto 3 gallons of sweat in a day.
  5. Goose bumps help retain a layer of warm air over our body.

Vultures – Facts and Information

Which category of birds do vultures come under?

A vulture is a scavenging bird of prey which plays a very important role in maintaining the ecosystem by eating dead and rotting animal carcass, in the wild.

What do vultures eat?

They usually eat carrion, although sometimes they attack newborn or wounded animals. Vultures generally go without food for long periods of time. So once they do find something to eat, they eat their fill. Vultures have a throat pouch called a crop, which is used to store food to be consumed later or to feed young ones.

What are the types of vultures found around the world?

Vultures are practically found all over the world except Australia and Antarctica.
Vultures can be divided into two groups.

1. Old World Vultures

They are found in Asia, Africa and Europe.
They look like their eagle, hawk, buzzards and kites species. They have grasping talons and voice box to vocalise with and build their nests on trees or rocky crevices with twigs. They find carcasses exclusively by sight.

There are 16 identified species of old world vultures.

  1. Cinereous vulture
  2. Griffon vulture
  3. White-rumped vulture
  4. Rüppell’s vulture
  5. Indian vulture
  6. Slender-billed vulture
  7. Himalayan vulture
  8. White-backed vulture
  9. Cape vulture
  10. Hooded vulture
  11. Red-headed vulture
  12. Lappet-faced vulture
  13. White-headed vulture
  14. Bearded vulture (Lammergeier)
  15. Egyptian vulture
  16. Palm-nut vulture

2. New World Vultures

They are from North, Central and South America.
They have a distinctly bald head, an adaptation that reduces the risks of disease, because bacteria might grow in feathers with blood and meat caught in between.
New world vultures have nostrils that are long and horizontal with a space between them. Some species have highly developed smells. They do not have a voice box and hence cannot make any sound except grunts and hisses.
They do not build nests, but lay their eggs in holes in rocky crevices or hollows of trees.

There are 7 identified species of new world vultures.

  1. Black vulture
  2. Turkey vulture
  3. Lesser yellow-headed vulture
  4. Greater yellow-headed vulture
  5. California condor
  6. Andean condor
  7. King vulture

What makes vultures unique as scavenging birds?

  • Vultures have a huge wingspan which allows them to stay in flight for long periods of time, without flapping their wings. This way they can soar at high altitudes without tiring and keep a look out for food, generally an animal that is dying, or is already dead. Once one vulture locates food, other vultures follow. There is generally a pecking order based on size.
  • They have incredibly sharp eyesight.
  • Their bodies are built for scavenging. Their extremely strong, sharp and hooked beaks can tear a carcass apart, but since they do not catch live animals, their talons are not as sharp as other birds of prey. Some vultures because of their smaller size, like the Hooded Vulture, have adapted to eating termites and lizards.
  • They have strong stomach acid, which is exceptionally corrosive and allows them to safely digest putrid carcasses infected with botulism, cholera, anthrax and even rabies that might be lethal to other scavengers.
  • They generally have bald heads and necks devoid of feathers, to avoid fostering bacteria growth that might be caused by blood and meat from carcass.
  • Vultures urinate on their legs and feet to cool off on days, a process called Urohydrosis. This also helps kill any bacteria or parasites they may have picked up on their talons.

4 Interesting facts about vultures

  1. Although they feed on dead animals, they bathe after eating.
  2. Vultures are relatively social and often feed, fly or roost in large flocks. A group of vultures is called a committee, venue or volt. In flight, a flock of vultures is called a kettle, and when the birds are feeding together at a carcass, the group is called a wake.
  3. The Indian vultures were on the verge of extinction because of the use of a veterinary drug found in carcass of livestock.
  4. The first Saturday in Spetember is recognised as International Vulture Awareness Day.

Marie Curie Biography

Who was Marie Curie?

Marie Curie was born on 7th November, 1867, in Warsaw, Poland. She was the first woman to win a Nobel Prize and the only woman to win the award in two fields of science, Physics and Chemistry. She died on July 4, 1934, in France, due to aplastic anemia, caused by prolonged exposure to radiation.

What is Marie Curie best known for?

She is the most famous female scientists of all times and has received several posthumous honours. Marie Curie made many breakthroughs in her life and she along with her husband Pierre Curie’s research led to the discovery of radium and polonium.

Early life and education

Born as Maria Sklodowska, and the daughter of teachers, Marie Curie was the youngest of five children and took after her father, Wladysław, with her aptitude for Math and Physics. At the age of 10, she lost her mother, Bronislawa, to tuberculosis.

A top student in her school, Marie Curie was unable to attend the men only University of Warsaw. She continued her education in Warsaw’s ‘Floating University’ informal classes, that were conducted.

Marie helped her sister Bronislawa to complete her medical studies in Paris, while she worked to support them, in exchange for the same support.

In late 1891, she left Poland for France and enrolled at the University of Paris, to study Physics, Chemistry and Mathematics. She underwent severe hardships while following through with her education. In 1893, she was awarded a degree in Physics and began working in an industrial laboratory of Professor Gabriel Lippmann.

Marie and Pierre Curie

With the aid of a fellowship, she was able to earn a second degree in 1894. Marie began her scientific career with a commission to study magnetic properties of different types of steels. She met her husband Pierre Curie around this time. Their mutual interest soon developed into deep feelings and they married.

Their eldest daughter Irene was a scientist and a Nobel Prize winner in Chemistry.

Marie Curie’s research and discoveries

  • In 1895, after Wilhelm Roentgen discovered the existence of X – rays and Henri Becquerel discovered that uranium salts emitted rays that resembled X – rays, Marie Curie decided to look into Uranium rays as a research thesis. This research brought Pierre and Marie their first Nobel Prize along with Henri Becquerel in Physics, in 1903.
  • Their journey continued with their work on X Rays, Radium and Polonium bringing them several accolades. Their contribution to science paved the way for nuclear and atomic energy sciences. Pierre Curie lost his life in 1906, due to an accident.
  • Marie Curie received her second Nobel Prize in Chemistry for her discovery of the elements, Radium and Polonium, in 1911.
  • In 1995, Marie Curie were enshrined in the Pantheon in Paris. She was the first woman to be honoured for her achievements.

Top 4 quotes by Marie Curie

  1. I am among those who think that science has great beauty.
  2. It was like a new world opened to me, the world of science, which I was at last permitted to know in all liberty.
  3. One never notices what has been done; one can only see what remains to be done.
  4. Scientist believe in things, not in person.

What is sound?

What is sound in physics?

Sound is a longitudinal, mechanical wave. It is caused by the back and forth vibration of the particles of the medium through which the sound wave is moving. The vibrations of the object set particles in the surrounding medium in vibrational motion, causing the auditory receptors to detect them. This is called sound.

Does sound need a medium to travel?

Yes, sound needs a medium to travel. It can travel through any medium, but it cannot travel through a vacuum. Sound is absent in outer space, as there is no medium to carry sound vibrations.

When the vibrations are fast, you hear a high note, and when the vibrations are slow, it creates a low note.

What are the components of a sound wave?

Wavelength – A sound wave is created due to pressure variations caused by vibrations. There are low pressure areas and high pressure areas. The high pressure areas are represented as crests and low pressure areas as troughs.

The physical distance between two consecutive crests or troughs in a sound wave is referred to as a wavelength.

Amplitude – In sound waves, amplitude refers to the magnitude of compression or expansion experienced by the medium the sound wave is travelling through.

High amplitude means loud noise. Low amplitude means low sound.

Pitch – Pitch/Frequency in a sound wave refers to the rate of the vibration of a particular sound travelling through air. It is calculated in cycles per second. The SI Unit for Frequency is Hertz.

The speed or velocity is calculated as frequency multiplied by wavelength.

Velocity of Sound = Frequency X Wavelength

What are the types of sound?

There are two types of sound, Audible and Inaudible.

  • Inaudible sounds are sounds that the human ear cannot detect. The human ear hears frequencies between 20 Hz and 20 KHz.
  • Sounds that are below 20 Hz frequency are called Infrasonic Sounds. Elephants use Infrasonic sounds to communicate with herds 100s of kms away.
  • Sounds that are above 20 KHz frequency are called Ultrasonic Sounds. Dogs, Bats can hear high frequency sounds.

6 Interesting facts about sound

  1. Sounds travel at 340.29 m/second at sea level and 20 degrees celsius.
  2. Sounds that are higher in frequency than audible sounds are known as ultrasonic sounds. Bats, whales, dolphins, dogs use ultra sound for echo location (to find either their location or to find or locate food, prey, or enemies and danger) and navigation.
  3. A cat can hear high frequency sounds two octaves higher than humans.
  4. Elephant communicate in sound waves in lower frequencies that human ears cannot detect.
  5. The study of sound waves is called acoustics.
  6. Flies are unable to hear any sounds.

Kingdom Classification of Living Organisms

What is classification of kingdoms of living organisms?

In biology, classification of kingdoms is very important as living organisms need to be classified to study and to understand them better.

Who created the classification of living things?

Classification of living things was first formalised by Carolus Linnaeus (also known as Carl Linnaeus), a Swedish botanist, and zoologist, in 1735. He classified all living things as Plants and Animals on the basis of nutrition and locomotion (mobility).

The two classification system however did not indicate an evolutionary relationship between plants and animals and grouped unicellular and multicellular organisms together and some organisms were not classifiable based on the limiting parameters, including viruses.

The classification of living organisms took on a new journey with the discovery of the microscope. New organism were discovered, and new classification became necessary. Today the classification of living organism consists of six kingdoms.

How did the six kingdom of classification come to be?

The German biologist Earnst Haeckel in 1866, in his book Generelle Morphologie der Organismen, had classified the living world into three kingdoms : Protista, Plants and Animals. The group Protista included all single celled organisms that are intermediate in many respects between plants and animals.

R H Whittaker, an American Taxonomist, classified all living things in a five kingdom classification in 1969. They were Monera, Protista, Fungi, Plants and Animals.

They were classified on the basis of:

  • Complexity of cell structure
  • Complexity of body organisation
  • The mode of nutrition
  • Life style (ecological role)
  • Phylogenetic (evolutionary) relationships

The six kingdoms of classification which is the current standard of classification of all living things was defined around 1980. It was defined by Carl Richard Woese, an American microbiologist.

He based this classification on his studies of ribosomal RNA. His studies made it possible to divide the prokaryotes into two kingdoms, called Eubacteria and Archaebacteria.

What are the six kingdoms of living organisms?

1. Archeabacteria –

  • They are very primitive single celled organisms that live in harsh and severe environments.
  • Prokaryote
  • No true nucleus
  • Unicellular
  • Autotrophic or Heterotrophic
  • Live in extreme conditions and are chemically different from Eubacteria

2. Eubacteria –

  • They are classified as true bacteria and have rigid cell walls.
  • Prokaryote
  • No true nucleus
  • Unicellular
  • Autotrophic or Heterotrophic
  • Live everywhere – “true bacteria”

3. Protist –

  • They are classified as neither plants, animals or fungi. They are generally unicellular.
  • Eukaryote
  • True nucleus
  • Most are unicellular
  • Autotrophic or Heterotrophic
  • Can be protozoa, algae, funguslike, autotrophic, heterotrophic, unicellular or multicellular

4. Fungi –

  • They are classified separately from plants because of the absence of cellulose in their cell walls and the presence of chitin, a hard substance uncommon in plant cells.
  • Eukaryote
  • True nucleus
  • Multicellular (except for yeast)
  • Heterotrophic
  • Digest their food outside of their bodies

5. Plant –

  • They are classified based on the fact that they are multicellular, have chlorophyll and can manufacture their own food.
  • Eukaryote
  • True Nucleus
  • Multicellular
  • Autotrophic
  • All multicellular autotrophs
  • Start food chains, no life on Earth without plants

6. Animal –

  • They are classified based on the fact that they are multi – cellular, have mostly internal digestive systems and do not have rigid cellular walls.
  • Eukaryote
  • True Nucleus
  • Multicellular
  • Heterotrophic
  • All multicellular heterotrophs
  • Largest known kingdom with over 1 million species

Degrees of Comparison in English

What are Degrees of Comparison?

Degrees of Comparison are adjectives that change form and are used to compare one thing or person to another.

They are applicable to adjectives and adverbs and not to nouns and verbs.

3 Types of Degrees of Comparison?

Degrees of Comparison are of three types.

1. Positive Degree

The positive degree of an adjective in comparison is the adjective in its simple form. It is used to denote the existing state of a person or thing and is used when no comparison is made.

2. Comparative Degree

The comparative degree of an adjective in Degrees of Comparison denotes the higher degree of the quality than the positive. It is used when two things or two sets of things are compared.

3. Superlative Degree

The superlative degree conveys the highest quality of a person or a thing. It is used when more than two people or things are compared.

Examples of the three types of Degrees of Comparision


Now let’s try an exercise. Fill in the blanks in the following sentence.

1. There are very few places as _________________ as Paris.
Option : pretty / prettier / prettiest
Answer : pretty Positive Degree
2. Of the two, who is __________________ ?
Option : tall / taller / tallest
Answer : taller Comparative Degree
3. This is the _________________ house in the neighbourhood.
Option : big / bigger / biggest
Answer : biggest Superlative Degree
4. There is nothing ___________________ than a glass of water.
Option : good / better / best
Answer : better Comparative Degree
5. There is nothing as ___________________ as a glass of water.
Option : good / better / best
Answer : good Positive Degree

Rational and Irrational Numbers

What are numbers?

A number is a mathematical object used to count, measure and label.
1, 2, 3, 4, etc are called natural numbers.

What is a rational number?

A rational number is a number that can be expressed as a fraction with an integer numerator and a positive integer denominator. Two different fractions may correspond to the same rational number.
1/2 = 2/4
Every whole number is a rational number. These can be written as N/1 = N, so they are rational numbers.

What is a negative rational number?

A rational number is said to be negative, if its numerator and denominator are of opposite signs, that is, one is a positive integer, and the other a negative one: example – -1/6, -30/11

What is an irrational number?

An irrational number is any number that is not rational. It is a number that cannot be written as a ratio of two integers or cannot be written as a fraction.
The square root of 7 is an irrational number.
If a fraction has a denominator of zero, it is an irrational number : example – 9/0

Is zero a rational number or an irrational number?

Zero (0) is a rational number as it can be computed as zero in a fraction. Zero divided by any integer will equal to a zero.

What is the difference between rational and irrational?

  • Rational numbers can be expressed in fractions, where the denominator is not zero. Irrational numbers cannot be expressed in fractions.
  • Rational numbers include perfect squares like 9, 16, 25, 36, 49 etc. Irrational numbers have to be left in their root form and cannot be simplified like 2, 3, 5, 7, 11 etc.
  • Rational numbers include decimals which are finite and repeating. Irrational numbers include numbers whose decimal expansion is infinite, non- repetitive and shows no pattern.

3 Fun facts about rational and irrational numbers

  1. π (Pi) is a famous irrational number. You cannot write down a simple fraction that equals Pi.
    The value of π = 3.14159265358979323846264338327950288419716939937510…
  2. The Golden Ratio is an irrational number. Two quantities are in the golden ratio if their ratio is the same as the ratio of their sum to the larger of the two quantities.
    The first few digits of the golden ratio = 1.61803398874989484820…
  3. The square root of the number two is an irrational number.

Types of questions in English

Different types of questions in English

There are many types of questions that the English language has. A sentence which asks a question is known as an Interrogative sentence. But every interrogative sentence is not the same. Here are the different types of questions in English.

1. Yes/No questions

This is the simplest type of question in English Language. These types of questions are such which expect the answers as either a Yes or No. Though, sometimes they can be accompanied with a reason but not always.

Can I have a glass of water?
Do you like mangoes?
Did you hear what I said?

2. Choice questions

These types of questions ask the other person to choose between two or more options, which are presented to them. These options are connected to each other using the conjunction OR.
Would you like to have chocolate or butter scotch?
Who do you like more, Harry or Ron or Hermione?
What do you prefer, dogs or cats?

3. ‘Wh’ questions

These are those questions that start with the words having ‘Wh’ in them. Such words are: Why, when, where, what, who, whose, which
What is your name?
When is the movie going to start?
Whose book is this?
There are other questions that do not start with ‘Wh’ but do fall in this category. These are the ‘how’ questions.
How are you?
How much is that shirt for?

4. Indirect Questions

These are also known as embedded questions. They are not asked directly but are embedded within another sentence or question. They are either polite questions or reported speech.
Could you tell me if the next train is on schedule? (indirect)
Is the next train on schedule? (Direct)
I was wondering if I can have a piece of the cake? (Indirect)
Can I have a piece of the cake? (Direct)
Do you know where I can find a water filter? (Indirect)
Where can I find a water filter? (Direct)

5. Rhetorical questions

These are such questions that do not expect any answers and are used for expression or stylist purposes. Such questions are mostly expressions or reactions. This is the reason why they are mostly written with an exclamation mark instead of a question mark.
Are you really serious?
What! I really got the job?
Girl- I think I will have to cancel the meeting today?
Boy- What? But everything is scheduled.

Understanding the four types of questions worksheet

1. Use the different words to form Yes/No questions:

You, Delhi, from, Are

  • From Delhi, are you?
  • You are from Delhi?
  • Are you from Delhi?

Right Answer Are you from Delhi?

They, do, horses, have

  • Do they have horses?
  • Have horses, do they?
  • They horses, do have?

Right Answer Do they have horses?

2. Form Wh/how questions:

Dinner, is, what, for

  • What dinner is for?
  • What is for dinner?
  • What for is dinner?

Right Answer What is for dinner?

Spell, name, your, you, do, how

  • How you do spell your name?
  • How your name do you spell?
  • How do you spell your name?

Right Answer How you do spell your name?

3. Change these direct questions into indirect questions:

  • What do you mean by that?
  • What do you mean by that, tell me?
  • What you do mean by that, tell me?
  • Tell me, what do you mean by that?

Right Answer Tell me, what do you mean by that?

  • What are your plans?
  • Would like to know your plans?
  • I would like to know what are your plans?
  • What plans do you have?

Right Answer I would like to know what are your plans?

4. Which of these are rhetorical questions?

A1. a. How are you? b. Sure, why not? (Right Answer)

A2. a. Are you sad? b. Are you kidding me? (Right Answer)

A3. a. Is there anything I can do? b. Where have you been all my life? (Right Answer)

Swami Vivekananda Biography

Where was Vivekananda born?

Swami Vivekananda was born Narendranath Datta on 12th January, 1863, to an aristrocratic Bengali family of Calcutta. His father, Vishwanath Datta was an attorney at the Calcutta High Court, and his mother, Bhubaneshwari Devi was a devout housewife. The progressive and rational thinking of his parents mixed with a deep rooted spirituality shaped young Narendranath’s mind.

As a young boy, Swami Vivekananda excelled in music, gymnastics and studies. He went on in life to become one of the greatest Indians to introduce the philosophies of Yoga and Vedanta to the Western world. He is also credited with raising interfaith awareness, bringing Hinduism to the status of a major world religion during the 19th Century.

Early Years

Swami Vivekananda was one of nine siblings. He was spiritually inclined at an early age, fascinated by wandering ascetics and monks.

His education was both a mix of Western and Indian worlds. He studied Western philosophies, religion, history, social science, art and literature along with the Puranas, the Ramayana, the Mahabharata, the Bhagavad Gita, the Upanishads and the Vedas. Around this time, he was also briefly introduced to the Brahmo Samaj.

In 1881, he passed the Fine Arts examination and completed his Bachelor of Arts degree in 1884, from General Assembly’s Institution, where the principal described him to be a genius, with an amazing sense and understanding of philosophies.

Over the course of several years, Swami Vivekananda studied various schools of esoteric philosophies. He first met Ramakrishna Paramahamsa, who was to later become his Guru, in 1881. His meeting with Ramakrishna again in 1884, after his father’s death, was a life changing event.

He turned toward a monastic life and after Ramakrishna’s death from throat cancer, Swami Vivekananda and the other disciples were left without shelter. He decided to convert a dilapidated house to establish the first Ramakrishna Math at Baranagar and start the monastic order of Ramakrishna.

Monastic Vows and Life After

Swami Vivekanada took his formal monastic vows along with the other disciples, in 1886. He assumed the name Swami Vivekananda much later.

In 1888, Swami Vivekanada left the monastery after receiving the blessings of Sarada Devi, Ramakrishna’s wife and embarked on a journey around India.

The Ramakrishna Mission

The more he travelled, he understood, how poor and backward the masses were. And how important it was to uplift the poor, educate both men and women, and this sowed the seed for the Ramakrishna Mission.

After he had travelled for five years around India, he travelled to the United States of America, after spending a few months in Japan, China and Canada. He attended the Parliament of World’s Religions on 11th September, 1893, at Chicago, where he spoke on Vedanta, Advaita and Hinduism and its philosophies.

He spent three years, lecturing, touring, travelling around the various cities of United States of America.

Back to India – 1897 – 1899 and Death

Swami Vivekananda established the Ramakrishna Mission on 1st May, 1897, in Calcutta. Its ideals were based on Karma Yoga. He further established two other ashrams, one in Mayavati, near Almora and one in Madras (Chennai), and founded two journals.
After another tour of the United States and France, Swami Vivekananda settled down at the Belur Math. On July 4th, 1902, he left his earthly body and attained samadhi.

Swami Vivekananda – Legacy

He inspired the freedom fighters of India like Bal Gangadhar Tilak, Netaji Subhas Chandra Bose, Gandhiji. Nobel Laureate Rabindranath Tagore is also deeply influenced by his writings and teachings. His influence to this day extends into Hinduism, the way we look at Neo -Vedanta and Advaita philosophies.

Swami Vivekananda – Teachings

  1. New Understanding of Religion and the explanation that reality is common to all humanity and that science and religion are not contradictory but complementary.
  2. New View of Man
  3. New Principle of Morality and Ethics
  4. Bridge between East and West

His birthday is celebrated as National Youth Day.

Swami Vivekananda – Quotes

  1. All that man has to do is to take care of three things; good thought, good word, good deed.
  2. Self-sacrifice, indeed, is the basis of all civilisations.
  3. Please everyone without becoming a hypocrite or a coward.
  4. The real individuality is that which never changes and will never change; and that is the God within us.
  5. Strength is the property of everyone in spite of all apparent weakness.
  6. Through education comes faith in one’s own Self.

What is a phrase?

Definition of phrase in English

A group of words that do not use a subject or a predicate to communicate a thought and is used as part of a clause. A phrase is used as a mode of expression and is always incomplete on its own.

Identify the phrase


It was a very bright, sunny day.
It was a very
bright, sunny day.
Answer: Phrase

He was walking on the cool, wet grass.
He was walking on the
cool, wet grass.
Answer: Phrase

The tower has steep and high steps
The tower has steep and high steps
Answer: Phrase

9 Types of phrases

Phrase have been classified into 9 types.

1. Noun Phrase

This type of phrase acts like a noun in a sentence.
She has a very nice smile
Answer: Noun Phrase
He has made a very comfortable life for himself.
Answer : Noun Phrase

2. Prepositional Phrase

This type of phrase uses an object of preposition (noun or pronoun) and a preposition. It uses words like before, after, near, on, above, at, in a, etc.
The cat with him is an expensive pedigree.
Answer: Prepositional Phrase
There are several rare plants by the river.
Answer: Prepositional Phrase

3. Adjective Phrase

This type of phrase acts like an adjective in a sentence. It modifies a noun or a pronoun.
The unicorn has a beautiful blue tail.
Answer: Adjective Phrase
The girl from my town won a scholarship.
Answer: Answer : Adjective Phrase

4. Adverb Phrase

This type of phrase acts like an adverb in a sentence. It modifies a verb, adverb or an adjective. It has words like how, when, where or why.
It’s funny how quickly time passed.
Answer: Answer : Adverb Phrase
He worked from home for a few hours.
Answer: Answer : Adverb Phrase

5. Verb Phrase

This type of phrase has a verb with another helping verb. It uses words like am, is, are, was, were, being, may, might etc.
He may need some help with his homework.
Answer: Answer : Verb Phrase
She did do what she had set out to do.
Answer: Answer : Verb Phase

6. Infinitive Phrase

These type of phrase uses an infinitive which acts like a noun, an adjective or an adverb.
He lives to please others.
Answer: Answer : Infinitive Phrase
I have a desire to drive a car.
Answer: Infinitive Phrase

7. Gerund Phrase

This type of phrase uses a gerund to complete a thought. The gerund phrase functions like a noun.
The cawing crows were such a nuisance.
Answer: Gerund Phrase
We had lots of fun trying to cook outdoors.
Answer: Gerund Phrase

8. Participle Phrase

This type of phrase uses either present participle or past participle verb and acts like an adjective. It uses a comma or commas to punctuate in a sentence.
The young mother, raising her kids, needs extra support.
Answer: Answer : Participle Phrase
The sky, turning a pale shade of pink, was a sight to behold.
Answer: Answer : Participle Phrase

9. Absolute Phrase

This type of phrase is called a nominative phrase. It uses a noun, a pronoun or a participle and tells more about the sentence. It looks like a clause, but doesn’t have a true finite verb. It is separated by a comma in a sentence.
The storm having left, the city calmed down.
Answer: Answer : Absolute Phrase
After the sun had risen, the boys set out on their trek uphill.
Answer: Answer : Absolute Phrase

Try this fun exercise and identify the types of phrase.

He was walking in the forest and came across a small hut made of spun sugar. The house was pink and yellow. He told himself, this must be the hidden kingdom of fairies. He heard hushed laughter. The laugh sounded like that of a fairy. He looked around to a see small fairy playing with the caterpillar. The caterpillar was sad. It was time for him to go into his cocoon. The fairy teased him and said he would come out looking ugly. No one was as pretty as the fairy. The boy walked closer to the fairy. The fairy and the caterpillar disappeared.

  • was walking (Answer : Gerund Phrase)
  • made of spun sugar (Answer : Adjective Phrase)
  • must be (Answer : Verb Phrase)
  • hushed laughter (Answer : Noun Phrase)
  • looked around (Answer : Verb Phrase)
  • playing with the caterpillar (Answer : Participle Phrase)
  • to go (Answer : Absolute Phrase)
  • come out looking ugly (Answer : Prepositional Phrase)
  • pretty as a fairy (Answer : Adjective Phrase)

Nikola Tesla Biography

If we ask you to look up the encyclopedia and find out who invented the radio or X-rays, neon lights that we use so often in the parties or the microwave that we use every day in the kitchen, you will never find anything about Nikola Tesla there. But the fact is otherwise! It was Nikola Tesla who did the main homework for the development of all the aforementioned things and the technology behind them. Yes, whether you believe it or not, the truth is that even though Tesla lived about a hundred and sixty years ago, he helped in developing technology that is used by all of us every single day. Sadly, he was never given the credit he truly deserved due to some unfortunate circumstances.

Early childhood

Nikola Tesla was born on July 10, 1856 in Smiljan, Croatia. His mother was an inventor and his father was a priest. His parents wanted him to become a priest like his father, but he had a passion for studying Science. He studied Science at the University of Prague and then started working for the Central Telephone Exchange in Budapest.

Tesla and Edison

At the age of 28, Tesla decided to go to America in pursuit of his desire to create new inventions. Upon moving to the United States, Tesla started working with the famous American inventor, Thomas Edison. While working together, a disagreement occurred between Tesla and Edison over Edison’s direct current and Tesla’s alternating current. This was also known as the “war of the currents.” Edison lamps were supplied with direct current which made them weak and inefficient. The direct current could not travel for long distances. On the other hand, Tesla’s alternating current was able to travel long distances on distribution lines, first in one direction, and then in another in multiple waves.

Tesla Electric Light Company

The disagreements created a lot of bitterness between the two scientists and Tesla eventually left Edison to create his own company called the Tesla Electric Light Company. His work caught the attention of another American inventor, George Westinghouse. They joined hands and started working together to generate electricity for the nation. Edison and Tesla were now in direct competition for providing America with energy and power. In 1893, Tesla’s AC electrical system was selected over Edison’s at the World’s Columbian Exposition in Chicago. It was a big accomplishment for Tesla. But, as luck would have it, Westinghouse ran into financial trouble and Tesla had to walk out of the partnership by selling his patent.

Wireless Broadcasting System

A year later, in 1896, Tesla created the world’s first hydroelectric power plant, which brought power to the city of Buffalo, New York. This invention brought Tesla considerable fame and recognition for a short while. During 1899 to 1900, Tesla continued to experiment with electricity and radio frequency magnetic waves in his laboratory based in Colorado. In 1900, supported by financier J.P. Morgan, Tesla started construction of a “Wireless Broadcasting System” tower on Long Island, New York. The aim of constructing this tower was to connect telephone and telegraph services, as well as broadcast images, reports, and weather information to every corner of the world. But due to certain reasons, J.P. Morgan had to cut funding and the tower had to be sold off.

Research gets stolen!

Tesla never had the gods of destiny working in his favor and there was more to come. During this period of turmoil, Tesla’s research work was stolen and used as their own by his contemporary scientists. Marconi is alleged to have passed off Tesla’s work on long-distance radio transmission as his own. Tesla decided to sue Marconi but it was too late. Though Tesla’s patents were prior to Marconi, the national press was out rightly supporting Marconi and the judge did not know a thing about modern technology. Naturally, Tesla lost his case. Much Later, in 1943, the US Supreme court conducted a detailed investigation, reversed the old decision given by the court and granted recognition to Tesla, nullifying Marconi patents.


You would be surprised to know that Tesla had over 800 different patents to his name, and despite that he was penniless. Ridicule from his own colleagues, lack of recognition by the public, drove him into a life of depression and self-imposed exile. He started jotting down his theories and research activities in his diaries and notebooks instead of getting them published anywhere. It is absolutely ironical that the man who invented the modern world died a pauper in a lonely hotel room on January 7, 1943 at the age of 86. Half a century after his death, scientists are still trying to comprehend and study his various theories. Many of them are just now being proven. It is indeed sad that we never managed to recognize and appreciate a true genius like Tesla in his lifetime. But, now that you know all about him, you can make an endeavor to give Nikola Tesla his due credit, no matter belated it is.

Famous Quotes

  • “I dont care that they stole my idea . . I care that they dont have any of their own.”
  • “My brain is only a receiver, in the Universe there is a core from which we obtain knowledge, strength and inspiration. I have not penetrated into the secrets of this core, but I know that it exists.”
  • “The scientific man does not aim at an immediate result. He does not expect that his advanced ideas will be readily taken up. His work is like that of the planter – for the future. His duty is to lay the foundation for those who are to come, and point the way. He lives and labors and hopes.”
  • “I do not think there is any thrill that can go through the human heart like that felt by the inventor as he sees some creation of the brain unfolding to success . . . Such emotions make a man forget food, sleep, friends, love, everything.”
  • “The scientific man does not aim at an immediate result. He does not expect that his advanced ideas will be readily taken up. His work is like that of the planter—for the future. His duty is to lay the foundation for those who are to come, and point the way.”
  • “All that was great in the past was ridiculed, condemned, combated, suppressed — only to emerge all the more powerfully, all the more triumphantly from the struggle.”

11 Interesting fun facts about Nikola Tesla

  1. Tesla suffered from insomnia and obsessive compulsive behavior (OCD).
  2. Tesla was a genius in the true sense of the word; he could speak 8 languages and had the ability to memorize a large amount of information. You could ask him to recite any portion from anywhere from his book and he would have done it in a jiffy!
  3. He was extremely fond of pigeons.
  4. The International Unit of Magnetic Flux Density is called “Tesla” after him.
  5. Tesla discovered X-ray radiation years before Roentgen was credited with its discovery.
  6. Tesla had proposed to build a radio controlled boat to the U.S. military.
  7. Though Tesla did not invent the light itself, he did find out the way to harness and distribute light over long distances.
  8. He also predicted the internet by once saying: “The household’s daily newspaper will one day be printed ‘wirelessly’ in the home during the night”.
  9. He claimed to have designed a death ray that could electrocute the enemy army from a distance of over 200 miles.
  10. His work with electromagnetic waves resulted in the invention of the radio, radar and the MRI, a type of X-Ray that has enabled us to look inside the human body
  11. During World War I, different countries were desperately looking for ways and means to detect enemy submarines under water. Tesla proposed the use of energy waves – the present day radar system technology – to detect the subs. However, the idea was rejected by all the scientists and military establishments as absurd and far-fetched. Sad, isn’t it? So, what happened thereafter? Well, the world then waited many more years for radars to be re-invented.

What is a clause?

Definition of clause

A clause is a group of words that has both a subject and a predicate. Every complete sentence is made of atleast one clause.

Examples: Michelle runs every morning.
The sentence has both :
Subject – Michelle
Predicate – runs
The sentence has one subject – Michelle. It speaks about Michelle, who runs every morning. So the sentence has one clause.

Different types of clauses with examples

Independent clause

These clauses can complete a sentence independently.

Tara is a marathon runner.
This sentence has one clause. It is a simple sentence. You don’t need another clause, to complete it to speak about Tara’s action.
If we need to describe more about Tara, then we need to add more clauses. This makes the sentence compound, complex or compound – complex. The clause that we add will then be a dependent clause or clauses.

Most sentence we use in our language are complex. These sentences are complex.
Michelle runs every morning, but she has never run a marathon.
Tara runs the marathon, because she is fit and strong.
It has one subject and two clause. Can you find them and identify which is the main clause and which is the sub-ordinate clause?

Michelle runs every morning, but she has never run a marathon.
Michelle runs every morning.
Answer : Main Clause
she has never run a marathon
Answer: Subordinate Clause

Tara runs the marathon, because she is fit and strong.
Tara runs the marathon
Answer : Main Clause
because she is fit and strong.
Answer : Subordinate Clause

Dependent clause

A dependent clause cannot complete a thought to be communicated on its own. It will need another clause to complete the sentence.

Dependent or sub-ordinate clause are of three types:

1. Noun clause

The noun clause plays the role of a noun in a sentence. Noun clauses contain a subject and a verb. They cannot stand on their own because they are not a complete thought and must be paired with the main clause. When using a noun clause, no commas are used.

Noun clause use words like Who, Whom, Whose, Which, Whoever, Whatever, Whenever, Whether, That if, What etc, to complete a thought when a single noun is not enough.

2. Adjective clause

The adjective clause plays the role like an adjective and modifies a noun or pronoun. it contains a subject and a verb that provides a description. Adjective clauses do not change the basic meaning of the sentence. They use commas if they are adding information to the sentence.

Adjective clause use words like That, When, Where, Who, Whom, Whose, Which and Why to provide information that is necessary for identifying the word it modifies. It provides additional meaning to a word which is already clear and always contains a subject and a verb.

3. Adverb clause

The adverb clause plays the role of modifying a verb, a clause, another adverb or any other phrase with the exception of determiners and adjectives that directly modify nouns.

Adverb clauses contain subordinate conjunctions that prevent them from containing complete thoughts and becoming full sentences. Adverb clause always answer the questions When, Why and How in a sentence.

Identify the type of clause

1. Is this the white dress you wore last week?
· Noun
· Adjective
· Adverb
Answer – adjective clause

2. The doctor said she was ill and that she should take her medicine.
· Noun
· Adjective
· Adverb
Answer – noun clause

3. You may practice piano till 7 pm daily.
· Noun
· Adjective
· Adverb
Answer – adverb clause

4. Whatever you choose will be fine.
· Noun
· Adjective
· Adverb
Answer – noun clause

5. The house that I once lived in is for sale.
· Noun
· Adjective
· Adverb
Answer – adjective clause

6. Please sit down whenever you drink water.
· Noun
· Adjective
· Adverb
Answer – adverb clause

7. The lady who drives the red car lives next door.
· Noun
· Adjective
· Adverb
Answer – adjective clause

8. The magical frog disappeared whenever someone appeared.
· Noun
· Adjective
· Adverb
Answer – noun clause

9. They have a cat that likes boiled fish.
· Noun
· Adjective
· Adverb
Answer – adjective clause

What is the Pythagorean Theorem?

Who was Pythagoras?

Pythagoras was a Greek philosopher and is a revered mathematician who lived from 570 to 495 BC. As a mathematician, he is known as the father of numbers, or a pure mathematician.

He is given credit for the Pythagorean Theorem, though the concept has been recorded by the Babylonians.

Pythagorean Theorem Formula

Pythagorean Theorem states that in a right angled triangle, the square of the hypotenuse is equal to the sum of the squares of the other two sides.
a2 + b2= c2

What are the Pythagorean Triples?

The Pythagorean Triples are the three integers used in the Pythagorean Theorem, which are a, b and c.

Why is the Pythagorean Theorem important?

  • Pythagorean Theorem is important because you can find out if the triangle is acute, obtuse or a right angle triangle. If the sum of two squared sides is equal to the squared value of the third side, which is the hypotenuse, then, the triangle is a right angle triangle.
  • The Pythagorean Theorem can also help you find missing side lengths of a triangle. You can find the third side length to a right triangle, but also find the missing side lengths to squares and rectangles when the triangles are pushed together. The Pythagoras Theorem can help build rectangles and squares.
  • Builders use the Pythagorean Theorem to help keep right angles and build houses, roofs, stairways etc.
  • Although a very fundamental principle today, the Pythagorean Theorem serves as the basis of the Euclidean distance formula and can be found in almost all aspects of our lives, including calculating the shortest distance between two points, if we are travelling.

Rabindranath Tagore Biography

Rabindranath Tagore was one of the most famous wordsmiths of India. He was also known as “Gurudev” or the “Poet of poets” for having cast an unforgettable impression on the minds and hearts of his readers.

Early childhood

Rabindranath was the youngest of the thirteen children born to Debendranath Tagore and Sarada Devi. He was born on 7th May 1861 in Calcutta, Bengal. Rabindranath was fondly called “Rabi” by his parents. His father was a well-known Hindu philosopher and social reformer who introduced little Rabi to the world of theatre, music and literature at an early age. A child prodigy, Rabindranath wrote his first poem when he was merely seven. He did his early education at home and spent most of the time in the lap of nature.

Education and work

In 1878, he was sent to Brighton, England, to study law, but he failed to complete his studies and returned to Bengal in 1880. Back in his hometown, he devoted himself completely towards his love for reading and writing. In 1882, he wrote one of his most acclaimed poems, ‘Nirjharer Swapnabhanga’. In 1883, Tagore married Mrinalini Devi and fathered five children. In 1890, his compilation of poems, ‘Manasi’ was released. The period between 1891 and 1895 saw the release of his collection of short stories, ‘Galpaguchchha’.


In 1901, Rabindranath founded Santiniketan, meaning ‘Abode of Peace’, an international university with an extensive and flexible curriculum suitable for students with different aptitudes and needs. This was perhaps the most glorious and happy period in Rabindranath’s life but things were about to change. Sadly, between 1902 and 1907, Tagore lost his wife, son and daughter. Out of his anguish, emerged some of his most sensitive and critically acclaimed work Gitanjali that was published in 1910. It was authored in traditional Bengali dialect and comprised of 157 poems based on nature, spirituality and complex human emotions.

Gitanjali and Nobel prize

Rabindranath’s popularity grew manifold after the publication of Gitanjali in India as well as abroad, and in 1913, he was awarded the Nobel Prize in Literature. He was the first non-European to win a Nobel Prize in Literature!

In 1915, he was granted knighthood by the British, which he relinquished as a symbol of protest against the 1919 Jalianwala Bagh massacre. During the 1920s and 1930s, he travelled extensively around the world; earning a huge fan-following. “Let us not pray to be sheltered from dangers but to be fearless when facing them”- these inspirational words of Rabindranath Tagore infused new life into the young Indian freedom fighters. He used to deeply admire Mohandas Karamachand Gandhi and it was he who gave him the title “Mahatma”.

Jana Gana Mana – Indian national anthem

Most of Rabindranath’s poems, stories, songs and novels talked about the social evils prevalent during those times such as child marriage and dowry. Tagore had composed about 2,230 songs, which are often referred to as ‘Rabindra Sangeeth’. We are sure that all of you know that it was Rabindranath Tagore who penned the national anthem for India – ‘Jana Gana Mana’, but do you know that he also wrote the Bangladeshi national song – ‘Aamaar Sonaar Banglaa’? Well, it is believed that even the national anthem of Srilanka is based on a Bengali song written by this famous historical figure!

Indian culture and Literature

Rabindranath Tagore loved to travel; during his lifetime, he visited more than thirty countries on five continents and spread the essence of Indian culture and Literature. His works have been translated into many foreign languages also including English, Spanish, German, Dutch etc. Even today, years after his death, this sage-like man, is alive in the hearts of the people of India through his treasured contribution in the realm of literature and music.

Standard Units of Measurement

What is a measurement?

Measurement maybe defined as a reference for the determination of quantities and qualities.

It is a repetition of a unit amount that maintains its size, within an allowable range of error, no matter which instrument is used and no matter what person or thing being measured is.

Why is a standardisation of measurements necessary?

Let’s suppose you were blind folded and you had to describe something. How would you do it?
If you know a set of specifications of object or person, you will be able to describe it, or if some one speaks about it, you will understand easily. But if you don’t know the specifications, it will be very difficult to describe or even form an opinion about it.
A standardisation of measurements is necessary because you need a consistent way to communicate size, shape, mass, time, energy, power, speed.

What are the different systems of measurements?

There are essentially three systems of measurements used all over the world. The Imperial or the English System, the US Customary Units and the Metric system.
The Metric System has been adopted as the Standard International Units of Measurement System in most countries.
The Metric system has been adopted because the conversion from lower values to higher values, and the reverse is possible easily and as multiples.

When did the Metric System come into use?

The Metric System came to be in use around the French Revolution, in 1799. The definitions of the base units have been modified since the Metre Convention, in 1875.
In 1960, these were standardised as the International System of Units.

What are the Standard International System of Units?

The standard (metric) units that are in use commonly include:

  • Weight : grams and kilograms
  • Length of Distance : centimetres, metres and kilometres
  • Fluid Mass Measurements : millilitres and litres
  • Temperature : kelvin although fahrenheit and celsius are used for everyday temperatures
  • Time : seconds, minutes and hour
  • Electric Current : ampere and kiloampere
  • Amount of Substance : mole and kilomoles
  • Luminosity : candela and kilocandela

5 Fun facts about measurement

  1. A ruler is a foot long and usually has inch and centimeter marks.
  2. A meter stick is a meter long and usually has foot, inches, and centimeter marks.
  3. Weighing Scales always use pounds, kilograms, ounces.
  4. Measuring cups are normally marked in cups and ounces.
  5. Non-standard measurements use approximate references like cubits, spans etc.

Fun Activity

  • Measure a square or rectangular object like a table, or your friend’s height. First use your arm and then use a measuring tape.
  • Note down how the measurement changes when you use a different hand to measure. Now you will understand why a Standard Unit of Measurement is required.

Difference between Electrolysis and Electroplating

What is electrolysis?

You must have heard that metals like iron and copper are extracted from iron ores and copper ores. Electrolysis is the process of separating or extracting the metal from the ore. Electric current is passed through the ore’s electrolyte/solution to result in a chemical change.

This chemical change is such that the substance loses or gains an electron. This process is known as Electrolysis.

What is electroplating?

Electroplating is the practical application of electrolytic cells. In this, a thin layer of metal is deposited onto an electrically conductive surface. In electroplating, the idea is to use electricity to cover or coat a relatively boring metal with a thin layer of another precious metal for it to look expensive.

A boring metal like copper can be coated with a thin layer of gold or silver and that is electroplating. Even in electroplating, it is required to pass electric current through a solution called electrolyte and the metal to be coated is dipped in the electrolyte.

Process of electrolysis

Electrolysis requires two oppositely charged poles. The cathode is negatively charged; it is the site of the reduction of positive ions. The anode is positively charged; it is the site of the oxidation of negative ions. In an electrolytic cell, these two poles are connected to an external power source. The circuit is typically completed by a salt solution called the electrolyte. In the production of metal through electrolysis, a layer of metal will form on the cathode.

Hydrogen gas and Oxygen gas are separated similarly from water.

Process of electroplating

Electroplating involves passing an electric current through a solution called an electrolyte. This is done by dipping two electrodes into an electrolyte and connecting it to direct current.

If we are copper plating some brass, we need a copper electrode, a brass electrode, and a solution of a copper-based compound such as copper sulfate solution.

We dip the two electrodes into the solution and connect them up into a circuit so the copper becomes the positive electrode (or anode) and the brass becomes the negative electrode (or cathode). When we switch on the power, the copper sulfate solution splits into ions. Positively charged copper ions are attracted to the negatively charged brass electrode and slowly deposit on it – producing a thin later of copper plate on the brass object to be coated.

What are the uses of electrolysis?

  • An important use of electrolysis is in the production of metals like aluminium, sodium, calcium, magnesium; or even the purification of metals like copper, gold and silver.
  • These days the electrolysis of water is used in the production of hydrogen for fuel or generation of electricity using fuel cells.
  • Our daily life would be very difficult without electrolysis. Example: the alkali used in making soap is produced by the process of electrolysis.
  • Did you know that astronauts and the people who live in submarines get their oxygen through the process of electrolysis?

What are the uses of electroplating?

  • Metals such as gold and silver are plated for decoration purposes. It is cheaper to have gold plated or silver plated jewellery rather than the pure form of gold or silver.
  • Then we have metals such as tin or zinc which are plated to give them a protective layer. This makes such metals resistant to corrosion.
  • Electroplating is also used to increase the layer of thickness in metals. Corrosion protection, wear resistance and lubricity are what electroplating provides to a metal.