a still is a tool used to clean a liquid. it does this by first boiling the liquid and turning it into a gas. this gas is then cooled, changing it back into liquid. stills get their name from the word di"still"ation. distillation is the process of boiling and cooling a liquid to purify it. stills are most often used to create alcohol, but they can also be used with any liquid. some examples are medicines and perfumes.