1. The Water Cycle

2. The Water Cycle
Evaporation
Sun heats water
Liquid water changes
to gas (vapor)
Water vapor rises
with warm air

3. Humidity
Warm Air Cold Air
 Amount of water
vapor, or moisture in
the air
 Changes with
temperature
 Warm air holds more
moisture than cold
air

4. Measuring Humidity
 Hygrometer is used to
measure the amount
of water vapor in the
air.

5. The Water Cycle
Condensation
 Water vapor cools
 Tiny water droplets
or ice crystals form
 Get bigger and
heavier

6. The Water Cycle
Precipitation
 Air can’t hold up
heavy water
droplets or ice
crystals
 They begin to fall

7. The Water Cycle
 All the different forms of water that
fall from the sky.

8. Precipitation
The air temperature determines the form of
precipitation.

9. Types of Precipitation
Rain
 Liquid
 Air temperature above 32 degrees Fahrenheit
Snow
 Solid
 Air temperature below 32 degrees Fahrenheit
Hail
 Solid
 Formed in clouds
 Winds carry frozen drops higher
 Layers of ice are added
 Repeats
Sleet
 Mixture
 Air temperature just above freezing

10. Measuring Precipitation
Rain gauge
 Open container that
collects precipitation
 Scale on side of
container shows how
much has fallen

11. The Water Cycle
Runoff
 Water that does not
soak into the ground
 Runs downhill into
puddles, streams, rivers,
or lakes
 Then the whole cycle
begins again

12. Review of the Water Cycle