The Water Cycle

One step of the water cycle is evaporation, the process of liquid water transforming into a gas. Most water vapor, gaseous water, in the air comes from evaporated ocean water. The rest comes from water that has evaporated over land through evapotranspiration. This includes water that evaporates from lakes and streams and even water vapor from animals’ breath. 

Once the atmosphere is full of water vapor due to evaporation, that water vapor condenses, or transforms from a gas to a liquid. This is why grass is covered with dew in the mornings; water in the air cools to form droplets. This water can then seep back into the soil through infiltration. However, most of the time water condenses high in the atmosphere, which forms clouds. Sometimes water condenses lower to the ground and becomes visible, which is called fog.

Clouds can grow and eventually release precipitation, or any water that falls from the sky in liquid or frozen form and reaches the ground. This includes rain, snow, hail, and sleet. Precipitation can be soaked into the ground. However, if there is too much water in one area to soak into the soil or the water is flowing too fast, runoff occurs. This is when water is drained from one area to another. Precipitation can be used by plants for photosynthesis, collected for drinking, or fall directly back into the ocean. In this way, water is cycled from one area to another over and over.