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.