Fractional distillation is a method to separate mixtures with different boiling points. It has been used since ancient times by Greek alchemists and in China during the Han dynasty. The process works by heating a mixture so it forms vapors, which rise up a fractional distillation column and condense based on their boiling points. Common uses are separating crude oil into hydrocarbon products like gasoline and separating chemicals in a lab. Current research is improving efficiency and applications in areas like oil refining.