Earth Learning

The Water Cycle

Paul Nathan Negrean

Paul Nathan Negrean

— 1 min read
The Water Cycle

The water we drink right now is approximately as old as when the world was created. The way this is possible is because it is recycled through the water cycle. This cycle explains how water moves between the Earth’s surface and the atmosphere.

This movement occurs by different processes:

  • Water moves into the atmosphere from all the water bodies through evaporation. When water changes from liquid to vapor (a gas) evaporation takes place.
  • Water also leaves the earth by evaporation of water from plants in a process called transpiration, similar to how we sweat. Both of these processes are caused by the sun’s energy.
  • Water turns into clouds by the process of condensation. During this process, water changes from water vapor to liquid water.
  • Water goes back to the Earth’s surface by precipitation. This process is caused by gravity. Out of the water that reaches land, some of it goes downhill as runoffs into water bodies and some soaks into the ground to become groundwater or into underground bodies of water.
A diagram shows mountains sloping down to land and a body of water. Trees are at the base of the mountains and clouds are in the sky. Different parts of the water cycle are labeled on the diagram as follows: 1. Evaporation from oceans, lakes, and streams. Arrows point from the body of water to a cloud in the sky. 2. Transpiration from plants. An arrow points from trees at the base of a mountain to a cloud in the sky. 3. Condensation. A cloud is shown in the sky. 4. Precipitation. An arrow in the rain points from a rain cloud to the top of a mountain. 5. Surface runoff. An arrow points from the middle of a mountain to the bottom. 6. Groundwater. Water is shown seeping into the ground.
The water cycle. Image credit: “Water cycle” by NASA, CC BY 2.0

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