- Millions of years ago, a large number of plants and ferns grew on Earth.
- These plants and ferns died in swamps, around riverbanks and got covered with soil and mud and slowly sank into the ground.
- As the years passed, the Earth’s heat and the weight of the ground changed these dead plants into coal.
- To extract coal, it needs to be dug out. Coal is usually found in layers, or seams underground.
Like fossil fuels like natural gas and oil, coal is formed by the transformation of organic matter. Plants that lived in vast swamps 300 million years ago are the source of most of the coal that is mined today. As those plants died, they sank into the swamps and were covered with sediments. Gradually, they decomposed into peat. As the peat sank, ground heat and pressure removed hydrogen, oxygen and nitrogen from it to leave mostly carbon. This is what we know as coal. Coal is classified by its carbon content- the greater the carbon content, the more heat it gives off when burnt. The lowest grade of coal is lignite, followed by sub-bituminous coal, bituminous coal and anthracite, which is 98 percent carbon.
THINGS TO DO3>
- Use coal to draw. Break a piece of coal to use like a pen for drawing.
- Try burning different types of coal and see which one burns the quickest and slowest.
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