UNIT SEVEN: Earth’s Water
 Chapter 21 Water and Solutions
 Chapter 22 Water Systems
 Chapter 23 How Water Shapes the
Land
Chapter Twenty-Two: Water Systems
 22.1 Water on Earth’s Surface
 22.2 The Water Cycle
 22.3 Oceans
Chapter 22.1 Learning Goals
 Identify places where water is found on Earth.
 Contrast the distribution of freshwater and
saltwater.
 Discuss the many beneficial uses of water.
Investigation 2B
Modeling a River
 Key Question:
Which variables affect the
formation of a river?
22.1 Water on Earth’s surface
 About 70 percent
of Earth’s surface
is covered with
water.
 This water is found
in oceans, rivers,
lakes, under the
ground, and as ice.
22.1 The hydrosphere
 All the water on Earth is part of a large system
called the hydrosphere.
 On Earth, water occurs in all three phases.
22.1 The distribution of water
on Earth
 About 97% of Earth’s
water is salt water
found in oceans while
2% is frozen at the
poles, leaving only
1% for human use.
If all the water on Earth could fit into a one-liter
bottle, only 10 milliliters would be fresh water.
22.1 Places where water is found
 Surface water on Earth refers to water that
collects on the ground.
 This water includes oceans, lakes, rivers,
streams, and reservoirs.
 A reservoir is a protected artificial or natural
lake that is used to store water.
22.1 Places where water is found
 A glacier is a huge mass of ice that forms on
land when snow and ice accumulate faster than
they melt.
 Most of Earth’s fresh water is in the form of
glacier ice.
22.1 Places where water is found
 Groundwater is water that collects under
ground.
 Some of the water on Earth’s surface moves
down through the soil to the water table (the
upper level of underground water).
22.1 Water as a resource
 The temperature
range on Earth’s
surface is just right
for water to exist in
all three phases—
liquid, solid, and
gas.
22.1 Water as a resource
 One of the reasons why water is so useful is
that it can dissolve many things.
 Over long periods of time, water dissolves and
wears down rocks and mountains through
processes called weathering and erosion.
22.1 Water as a resource
 The human body is 60%
to 75% water.
 When you eat food, water
in your body dissolves
nutrients so they can be
carried through your
bloodstream.