## 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

- A ruler is a foot long and usually has inch and centimeter marks.
- A meter stick is a meter long and usually has foot, inches, and centimeter marks.
- Weighing Scales always use pounds, kilograms, ounces.
- Measuring cups are normally marked in cups and ounces.
- 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.