Oil

Oil is a sticky, slippery and very thick liquid that you cannot mix with water. Oil rigts dig up oil that has been underground for millions of years. It is expensive because there isn't much of it and people use it to fill up their car with petrol. Not only is oil running out, but it is also damaging the environment.

You can help with the world's oil problem by walking or bicycling to school when you can and not doing too many things that require oil.