Describe how crude oil is separated into fractions in industry

Crude oil is made of many hydrocarbons that can have differing lengths. A hydrocarbons length determines it's boiling point due as a higher number of atoms in the chain means it has more Van Der Waals forces. The column is separated into fractions of different temperatures with the bottom one being the hottest and the top one being the coolest. When the hydrocarbon chains heat up their weak inter-molecular forces can break and they can become gaseous. Because of this the shorter hydrocarbons move higher up through the column until they reach a cooler temperature where they can then condense and be tapped off. The longest hydrocarbons are too stable to form a gas even at the highest temperature so they can be removed at the bottom.