Condensation is the changing of a gas or a vapor into a liquid by cooling. A cloud is a condensation of water vapor in the atmosphere. A substance boils and condenses at the same temperature.
When water boils, it turns into steam, a gas. At normal atmospheric pressure, this change happens at 212 °F (100 °C). Steam is colorless and transparent. The white mist often seen over the spout of a kettle is not actually steam. Rather, it consists of tiny droplets of liquid water. The droplets condense as invisible steam cools. The mist can be collected as distilled water.
Condensation usually begins first on solid surfaces, because they are generally cooler than the surrounding air. Dew forming on grass is an example.
See also Cloud ; Dew ; Distillation ; Fog .
