•When impurities are added to a substance, it would lower its freezing point.

•Impurities are other foreign substances.

•Example:

–I have 2 cups of water, A and B.

–I add salt to B. When I try to freeze the water in both cups, A would freeze at 0oC but B would freeze maybe at –10oC.

–This means B would stay as a liquid even at 0oC or -2oC or lower until the temperature reaches –10oC.

–When A becomes solid ice at 0oC, B is still liquid.