You think that plastic is non-living but was once part of a living thing.

You are correct!

Plastic is one of the many products which can be made from crude oil. To understand the origin of crude oil we need to go back millions of years. When the organisms which lived in the seas died their bodies fell to the sea beds. In some areas these dead organisms were not fully decomposed. Before this could happen changes in the Earth's crust caused the partly decomposed material to be buried between layers of rock. More earth movement caused some ancient sea beds to rise above sea level. This also caused high  pressure and temperature between the rock layers. The result of this activity is the natural gas and crude oil which we now extract by drilling down between the layers of rock.

Now try question 11

© Shirley Burchill 2008