THE WATER CYCLE
Water on Earth can be found in three states that are:
- Solid
- Liquid
- and Gas.
is the set of processes that water goes through as it changes from one state to another.
When the heat of the sun shines on the water in oceans, lakes, rivers and streams, the water evaporates, rising up into the air as water vapor. As it moves higher into the sky, it cools. The cooled water vapor begins to form liquid drops, which gather together as clouds. This process is called condensation. Little by little, more microscopic drops of water join together in the cloud. Finally, the cloud becomes so heavy that the drops start to fall. Any form of water that falls from the sky is called precipitation.
Precipitation will take on different forms. The form depends on the conditions that exist inside the clouds and the condition of the air the water travels through on its way to the ground. Drops of liquid water fall as rain, the most common form of precipitation. If the drops of water fall through air that is warmer than water’s freezing point, they will remain as rain. Sometimes cold temperatures inside clouds produce ice crystals that melt in warmer air on their way down, ending up as rain as well. If raindrops fall through air that is below the freezing point of water, they form tiny frozen drops known as sleet. If the air inside the cloud and the air on the way down are both below the freezing point, ice crystals will form and fall as snowflakes. There is a lot of variation in snow, depending on how cold it is when it falls. Warmer temperatures mean “wetter” snow, while colder temperatures mean drier, fluffier snow.
