Will cold water evaporate? - Colin Flaherty (age 10) Franklin, Massachusetts, U.S.A.
Yes, cold water can evaporate. Water is made up of tiny molecules that are always moving around. The constant movement builds up energy that eventually causes water to evaporate. However, cold water will evaporate much slower than it would if it was hot. When water is hot, the molecules move much faster leading to a quicker evaporation.
If the air is dry, you will see that even a cup of cold water will gradually evaporate away. If there's enough moisture in the air, however, there may be more water molecules coming in from the air than there are leaving the water. In that case the water level will go up. That's what happens at night when dew condenses on the cold ground.