Understanding the Water Cycle

We all know that water is the essential ingredient for life on Earth. Organisms cannot live without water. Water hydrates animals, transports nutrients, and is the universal solvent. There is only about 3 percent of freshwater here, on earth and only 31 percent of that 3 percent is drinkable by animals. The rest is found in ice caps and glaciers and therefore is undrinkable by animals.

The most important thing you should know is that heat drives the water cycle. Without heat there would be no evaporation nor transpiration and therefore it would throw off the whole cycle.

Heat is constantly enabling water to evaporate from lakes, rivers, streams, oceans, ice caps, and glaciers. Water also can evaporate from soil and organisms. 

When we think of the water cycle we think of evaporation, condensation, and precipitation. But there is more than just that. In the water cycle there is water vapor, evaporation, transpiration, condensation, precipitation, runoff, solar energy, groundwater, and percolation of water in the soil. In my opinion it is easier to think of the water cycle by starting with evaporation.


  Evaporation occurs when the heat of the sun turns water from its liquid state to its gaseous state. Another form of evaporation is transpiration. Transpiration occurs when trees, plants, and organisms release water in its gaseous state. All of this water vapor is released into the atmosphere. All of this water vapor goes into the stage of condensation which is the opposite of evaporation.


Condensation occurs when the water changes from its gaseous state to its liquid state. This happens because when the temperature lowers the vapor that is spread apart collects into water droplets that will soon go into the stage of precipitation.


Precipitation is when the water that is condensed in a cloud exceeds its capacity and can no longer be held in the cloud anymore. There are 3 types of precipitation: rain, sleet/snow, or hail. All of this water falls onto the earth. Some of it will fall into bodies of water.


The water that has landed at higher elevations will let gravity guide it to larger bodies of water. This is called runoff.

Percolation in Soil

Some of the runoff will be absorbed by the soil and be stored underneath the earth’s surface as groundwater. This groundwater will eventually make its way to the outskirts of the ocean.