Science Buddies: "Ask an Expert"

Can seawater be "desalted" by freezing?

The answer is no since the salt will remain trapped in the ice. However, if the water is boiled, the steam can be retrieved which is distilled water with no salt.

I agree with Mr. Gruenbaum's Expert reply, but in some cases some salt can be removed from saltwater by making it colder. If there is a lot of salt in the saltwater, lowering its temperature will lessen the water's ability to hold the dissolved salt. Some of the salt would crystallize again. Of course, distillation is the best method of desalinating water!