Refining crude oil involves separating its components based on their different boiling points through a process called fractional distillation. Crude oil is first heated to high temperatures in a distillation column. As it vaporizes, the vapor rises through the column and condenses at different levels depending on the boiling point of each component. The resulting products include gases, gasoline, kerosene, diesel, and residual oils. Additional processes such as cracking, reforming, and treating are then used to convert the heavy components into more valuable products, such as gasoline and diesel.