The Water Cycle

Standard E.8.1, Grade Level 4

Stages of the Water Cycle

Evaporation, Condensation, Precipitation, Accumulation, Transpiration, and Surface Runoff

Each stage in more detail

Evaporation = when the sun heats up water in rivers or lakes or the ocean and turns it into vapor or steam. The water vapor or steam leaves the river, lake or ocean and goes into the air.

Condensation = Water vapor in the air gets cold and changes back into liquid, forming clouds.

Precipitation = occurs when so much water has condensed that the air cannot hold it anymore. The clouds get heavy and water falls back to the earth in the form of rain, hail, sleet or snow.

Accumulation = When water falls back to earth as precipitation, it may fall back in the oceans, lakes or rivers or it may end up on land. When it ends up on land, it will either soak into the earth and become part of the “ground water” that plants and animals use to drink or it may run over the soil and collect in the oceans, lakes or rivers where the cycle starts

Transpiration = evaporation of water into the atmosphere from the leaves and stems of plants. Plants absorb soilwater through their roots and this water can originate from deep in the soil.

Surface Runoff = the water, from rain, snowmelt, or other sources, flowing over the land surface to ultimately reach streams

Types of Precipitation

Why is the water cycle so important?

Approximately three-fourths of the Earth is covered in water-- salt water. Of this water, approximately 1 percent is fresh water which we use and depend upon. The fresh water we use and its continuous replacement is a result of the water cycle. The earth has limited amounts of fresh water and if that water evaporated and never returned back to earth, we would not be living.