The Water Cycle
 The water cycle is the continuous movement of
Earth’s water from the ocean to the atmosphere to
the land and back to the ocean.
 Driven by energy from the sun.
 Contains the same water (same amount too!) since
the formation of the Earth
Water Cycle Rap
How did you flow as a water
molecule through the Water Cycle?
http://earthguide.ucsd.edu/earthguide/diagrams/watercycle/
Where can water exist on the Earth?
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Clouds
Ocean
Snow
Rain
Stream/River
Ocean
Lake
Ground water
Water Vapor
Glacier/ Ice
Living Things (People, animals, plans, etc)
Ground Water
 Groundwater is the part of precipitation that seeps down through the soil
until it reaches rock material that is saturated with water.
 Water in the ground is stored in the spaces between rock particles (no,
there are no underground rivers or lakes).
 Groundwater slowly moves underground, generally at a downward angle
(because of gravity), and may eventually seep into streams, lakes, and
oceans.
Ways that Water Travels through the
Water Cycle
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Evaporation
Transpiration
Infiltration
Condensation
Precipitation
Run-Off
Evaporation
 The sun heats liquid water, causing it to rise into the
atmosphere as water vapor.
 Water evaporates directly from oceans, lakes, rivers,
falling rain, plants, animals, and other sources where
the sun may excite water molecules.
Transpiration
 Transpiration is the process by which plants lose
water out of their leaves.
 Similar to an animal perspiring (sweating)
Infiltration
 Infiltration is the process in which water on the
surface ground enters the soil.
 The rate decreases as the soil becomes saturated. If
the precipitation rate exceeds the infiltration rate,
runoff will usually occur unless there is some physical
barrier.
Condensation
 Condensation takes place when water vapor cools and
changes into water droplets that form clouds in the
atmosphere.
 You can see the same sort of thing at home... Pour a glass
of cold water on a hot day and watch what
happens. Water forms on the outside of the glass. That
water didn't somehow leak through the glass! It actually
came from the air. Water vapor in the warm air, turns back
into liquid when it touches the cold glass
Precipitation
 Precipitation occurs when so much water has
condensed that the air cannot hold it anymore. The
clouds get heavy and water falls back to the earth.
 Precipitation forms in the follow ways:
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Rain
Snow
Sleet
Hail
Run-off
 Precipitation that flows over land into streams and
rivers. This water later enters the ocean, river or lake.
Distribution of Earths Water
Amount of Water on Earth
Pollution of Water
 Dirty water is the world's biggest health risk, and continues to
threaten both quality of life and public health in the United
States. When water from rain and melting snow runs off roofs
and roads into our rivers, it picks up toxic chemicals, dirt, trash
and disease-carrying organisms along the way.
 Many of our water resources also lack basic protections, making
them vulnerable to pollution from factory farms, industrial
plants, and activities like fracking.
 This can lead to drinking water contamination, habitat
degradation and beach closures.