What is fractional distillation and how does it work.

Fractional distillation uses a fractional distillation tower, split into different layers each with a different temperature. It is used to sperate crude oil into the many different fuels used commonly in everyday use and it is also commonly used to seperate liquified air.
It works by seperating the fractions to different temperatures, hotter at the bottom, and cooler at the top. What this does is allows only the more volatile fuels to be turned into a gas at each stage, and the less volatile stay as a liquid at the current stage of the process.