Transcript The Water Cycle - ESC-2

The Water
Cycle
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
• The water vapor rises into the atmosphere
and cools
• The cooled water vapor creates tiny water
droplets that form clouds
• When clouds become too heavy with water
droplets, precipitation falls
– rain
– sleet
– snow
– hail
• 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)
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
porosity
• Amount of water that a material can hold in
the spaces between the pores
permeability
• The measure of how well an earth material
can let water pass through it.
percolation
• The downward movement of water from the
land surface into soil or porous rock. It is
caused by gravity
infiltration
• When water enters the soil surface after
falling from the atmosphere
Surface water
• Water located on earth’s surface
• Most US cities use surface water
– rivers
– lakes
– streams
– ponds
– creeks
– reservoirs
ground water
• Water located under the ground surface
• Reached by using wells
• Cleaner and safer
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
http://www.epa.gov/safewater/kids/flash/flash_
watercycle.html
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?