British Sign Language Glossaries of Curriculum Terms

BSL Chemistry Glossary - fossil fuel - Definition

There are essentially three types of fossil fuel;

• coal that, for example, we burn in our fires;
• oil that we put in our cars and
gas, which we use for cooking

Fossil fuels formed millions of years ago - as trees died and fell to the ground one on top of another, over and over again, they built up layers, then over time these layers would sink and become impacted by the weight of other layers building on top of them. Over a period of something like 300 million years, this layer turned into coal which we now mine and then burn to help us keep warm, power the old steam trains and generate electricity using steam turbines.

Another, slightly different way fossil fuels formed again occurred millions of years ago. This time it was dying sea creatures that again built up layers which were then covered in mud and other sediment. They then rose up and made the rock above them bulge - this layer of Oil Rock has holes in it (‘Porous') which allows gas to escape and which is then trapped by the rock above it. The diagram shows the trapped gas and the layer of oil sitting beneath it.

Nowadays we extract fossil fuel by drilling and what comes up is either gas or oil. The oil is then used in cars and planes and various other things; the gas is used for cooking or to heat our homes.