When you look around, you will see water in different forms, from water forms near you to the liquids that you drink. You will not as readily see water in the air that you breathe but, indeed, air contains water.

Water can be in liquid form such as that in bodies of water. It can also be in solid form such as in glaciers and ice caps. Water can also be present in water vapor, the invisible gas in the air that you take in as you inhale. Perhaps you think all the water around you as new, yet each and every drop of water has already been around as part of a process known as the water cycle, or the continuous movement of water from the bodies of water to the atmosphere, to the ground, and back to bodies of water.

The cycle starts when the heat of the sun causes water from bodies of water to change to water vapor through evaporation. When water vapor reaches the atmosphere, it cools and turns into water droplets that form clouds through condensation. Water vapor that comes in contact with cold surfaces such as leaves and glass forms dew.

When clouds formed over land are cooled by air, they release the water droplets back to Earth in the form of sleet, hail, snow, or rain in the process called precipitation. Some droplets fall on land and are absorbed by the ground while some fall on bodies of water in the process called collection. Then the water cycle begins again.