Evaporation: When the sun's heat causes water to evaporate from surfaces such as oceans and rivers.
Condensation: The resulting water vapor rises into the atmosphere and cools, forming clouds as the vapor condenses into small water droplets or ice crystals.
Precipitation: When water droplets in clouds clump together and become large enough, they fall to Earth as precipitation, which can be in the form of rain, snow, hail, or drizzle.
Infiltration and Runoff: Part of the precipitation is absorbed by the soil in a process called infiltration. Water that does not infiltrate flows over the surface as runoff, reaching rivers, streams and bodies of water, and eventually returning to the oceans.
Storage: A part of the water that reaches the surface is stored in underground aquifers, which are reserves of groundwater in the soil.