Separating Mixtures by Temperature

There are three states of matter. These states are liquid, solid, and gas. Substances, like water, can exist in all three states. When liquid water reaches its freezing point, it turns into ice. Ice is a solid. Ice will return to a liquid when it reaches its melting point. If liquid water is heated, it will turn into a gas when it reaches its boiling point.

Each substance has a different boiling point, melting point, and freezing point. Some mixtures can be separated using hot or cold temperatures. For example, a mixture of sugar and water can be separated by using heat. Heat will separate the water and sugar using a process called evaporation. During evaporation liquid water is turned into a gas. After the water is removed, large chunks of sugar are left. People use heat to separate sugar from a mixture of sugar water to make rock candy.

When sugar is mixed with water, it dissolves. When the solution is heated and then cooled, the sugar molecules stick together again and form large crystals. This is how rock candy is made.View Larger Image

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