The Water Cycle Diagram
A good start toward understanding how the water cycle works is to see a pictorial representation as in the water cycle diagrams in this section. You can click on a diagram to enlarge it.
As the diagrams show, a major part of the water cycle is evaporation of water from the ocean into the atmosphere, movement of the air mass containing water vapor over land, and precipitation over the land. This precipitation puts water into rivers and streams, which flow back to the oceans, and it replenishes groundwater by infiltration. Underground water near the surface, called soil moisture, is taken up by plants through their root system, and a
large part of it goes back into the air through the plant leaves by a process called transpiration. Some of the precipitation which lands on the ground will "soak in" or infiltrate to replenish groundwater, and, if there is enough precipitation, some will become surface runoff to the nearest river, stream, or tributary.
Some of the water which evaporates from the ocean will go directly back into the ocean by precipitation. Water vapor also enters the atmosphere by evaporation from rivers, lakes, streams, and wet surfaces,