Page 221 - New Medley 5 Semester 2

FOSSIL FUELS

Millions of years ago, the dead plants and animals slowly got buried under the

layers of the earth and decomposed to form fossil fuels.

Coal, petroleum and natural gas are common fossil fuels. Today, they are used

to ful ll most of our energy demands.

Coal

Coal is a sedimentary rock. It was formed by the

decomposition of dead remains of trees, ferns and other
plants that lived 300 to 400 million years ago and got
buried in swamps. Coal

Coal is used as a fuel to run steam engines, in thermal power plants for generating
electricity and in blast furnaces in steel plants. It is also used for cooking,
manufacturing drugs, plastics, cosmetics, fertilisers, etc.

Petroleum

Petroleum is a black-coloured thick liquid

which is also called crude oil. It was formed
by the decomposition of organisms that lived
in water and got buried under ocean or river

sediments.

Petrol, diesel, kerosene, lubricating oil, wax and
medicinal oils are obtained from petroleum. Petrol/diesel Lubricating oil Kerosene
Some petroleum products

Knowledge Zone

The ‘green diesel’ or ‘cleaner diesel’ is a refined form of diesel which does not release black

smoke and smell. Hence, its use reduces air pollution.

Natural gas

e natural gas is found underground in deeper and hotter regions, near the

petroleum deposits.

Natural gas is used as a fuel. Nowadays, CNG (Compressed Natural Gas) is used

as a clean alternative to automobile fuel. It is also supplied to homes to be used
for cooking purposes. It is also used to manufacture fertilisers.

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