Water on the earth is being recycled continuously in a process known as the hydrologic cycle. The first step of the cycle is the evaporation of water in the oceans. Evaporation is the process of water turning into vapor, which then forms clouds in the sky. The second step is the water returning to the earth in the form of precipitation : either rain, snow, or ice. When the water reaches the earth's surface, it runs off into the rivers, lakes, and ocean, where the cycle being again.