This is the neverending circulation of water from clouds to earth to the ocean and back to the clouds again.

  1. The sun heats the earth’s water (lakes and streams) so it evaporates or changes its form to a vapor.
  2. As the air rises and cools, the tiny water droplets in the vapor get back together and form clouds.
  3. Water is returned to earth in the form of rain or snow.
  4. The rivers and streams also get water from melting mountain snow, and rivers ultimately flow into the oceans — and the cycle continues.
  5. Most of the earth’s water is underground in the tiny cracks and spaces in the rocks and soil. Large amounts of underground water are called “aquifers” that get “recharged” from rain, too.