Crude oil and other fuels is one area studied in GCSE Science. This is the fifth of six quizzes on that topic and it looks specifically at two methods of processing crude oil - 'cracking' and 'fractioning'.
Crude oil is formed from the remains of dead sea plants and creatures that became buried in the sediments of the sea floor millions of years ago. Ancient humans used crude oil that they found as 'pitch'. This gathered as pools where oil bearing rocks were exposed at the surface of the Earth. They used this thick and gooey substance for waterproofing their huts and perhaps even on the planks they used to make their boats. Come the modern era things changed. After the discovery was made of how to drill for it, crude oil become one of the most useful resources that we take from the Earth's crust.