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=**Water on the Move: The Water Cycle**=

What is the Water Cycle?
Water on Earth moves in a cycle that repeats itself over and over again. The same water moves above, below, and across the surface of Earth. The water cycle is the movement of water from Earth to the atmosphere and back again. The sun's heat energy warms the water and land on Earth's surface. This causes the water to warm up and it evaporates and turns to water vapor. Then the water vapor becomes part of the air. Water vapor also enters the air through transpiration. Water in the ground is taken up by the roots of plants. Any water the plants do not use moves into the atmosphere through transpiration.

After the air rises into the atmosphere it cools off. The water vapor starts to condense and the gas becomes tiny droplets of water that form clouds. The droplets join together and become larger and heavier. When the droplets are heavy enough they return to Earth as precipitation such as rain, snow, hail, or sleet.

The precipitation flows into rivers, lakes, and oceans as runoff. Some precipitation is absorbed into the ground in a process called infiltration and becomes groundwater.

The water cycle will then start again when the sun's heat energy warms the water and land on the Earth's surface again. This cycle never stops and water will continue to go round and round through the water cycle.

**Water Cycle Model**
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