2. UNIT SEVEN: Earth’s Water
Chapter 21 Water and Solutions
Chapter 22 Water Systems
Chapter 23 How Water Shapes the Land

4. Chapter Twenty-Two: Water Systems
22.1 Water on Earth’s Surface
22.2 The Water Cycle
22.3 Oceans

5. 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.

6. Modeling a River Key Question: Investigation 2B
Which variables affect the formation of a river?

7. 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.

8. 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.

9. 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.

11. 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.

12. 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.

13. 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).

15. 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.

16. 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.

17. 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.