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. 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

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

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

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

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

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

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

15. 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

18. 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?