Simple distillation is used to separate a liquid from a mixture, but when we want to keep the liquid.

1. The solution in placed in a flask and heated so that the liquid evaporates into vapour.
2. The vapour will pass into a condenser where it condenses back into liquid.
3. The liquid is collected in a beaker.

If the different liquids have similar boiling points, those liquids may evaporate at the same time.

Fractional distillation is used when the mixture contains multiple liquids with similar boiling points.

1. The solution is placed in a flask and gently heated.
2. The liquid with the lowest boiling point evaporates into a vapour and passes through the fractionating column.
3. As it passes into the condenser it condenses back into a liquid, and is collected in a beaker.
4. If another liquid had evaporated, it would have condensed again while passing through the fractionating column.
5. As the temperature is increased, the process repeats for the liquid with the second lowest boiling point, which is collected in a different beaker and so on.

The fractionating column is filled with small glass rods. These provide a large surface area which will cause gases to condense back into liquid if the temperature is below their boiling point.