Crude oil is made up of decayed organisms (mostly plankton) that died millions of years ago and became buried within the Earth's crust. It is a hydrocarbon mixture used as a source for fuels and plastics.

Fractional distillation is a method to separate crude oil into 'fractions' depending on the length of the hydrocarbon chains. It is very hot at the bottom and becomes cooler to the top to condense fractions at different points.

Going up the fractional distillation column the temperature decreases so fractions have lower condensation points. Using this information you can infer the other properties of the fractions.

Crude oil has a variety of applications in industry and everyday life.