1. The Water Cycle

2. The Sun The sun provides the energy to power the water cycle
The sun heats the upper ocean causing evaporation of liquid water into water vapor

3. The water vapor rises into the atmosphere and cools
The cooled water vapor creates tiny water droplets that form clouds

4. When clouds become too heavy with water droplets, precipitation falls
rain
sleet
snow
hail

5. Once water reaches the earth’s surface:
Infiltrates the surface (soaks in)
Runs across the top of the ground filling rivers, lakes, and streams (can cause erosion)

7. infiltration
When water enters the soil surface after falling from the atmosphere

8. Run off
Water moving along the surface of the earth before it enters a channel, such as a creek or a stream.

9. watershed
An area of land where the water drains into a body of water.

10. percolation
The downward movement of water from the land surface into soil or porous rock. It is caused by gravity

11. precipitation
Water condensed in the clouds falls to Earth in the form of rain, sleet, or snow.

12. Surface water Water located on earth’s surface
Most US cities use surface water
rivers
lakes
streams
ponds
creeks
reservoirs

13. porosity
Amount of water that a material can hold in the spaces between the pores

14. condensation
When water vapor cools and forms droplets on a surface.

15. aquifer
A natural underground area where large amounts of ground water collect and create an underground supply of water
Amount of water stored depends on the porosity and permeability of the sediment

17. permeability
The measure of how well an earth material can let water pass through it.

18. evaporation
The sun heats a body of water and causes the water to turn into water vapor.

19. ground water Water located under the ground surface
Reached by using wells
Cleaner and safer

20. water table
Underground area where the soil is permanently saturated with water.
The pressure of the water in the soil is the same as the atmosphere.

21. pollution
Any change to the environment that has a negative effect on living things.
Water sources are especially sensitive to pollution.
Burning fossil fuels can create acid rain.

24. Discussion Questions Is there a beginning to the water cycle?
What is the power source for the water cycle?
How does water get into an aquifer?