The solution is placed in a flask and gently heated. The liquid with the lowest boiling point evaporates into a vapour and passes through the fractionating column. As it passes into the condenser it condenses back into a liquid, and is collected in a beaker. If another liquid had evaporated, it would have condensed again while passing through the fractionating column. 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