1. Unit Essential Question: What would the world be like without water?
Fresh Water Chapter 11
Unit Essential Question: What would the world be like without water?

2. Water on Earth – Section 1
97% salt water
3% fresh water
Of the 3% of fresh water
Ice 76%
Water vapor 0.037%
Lakes and rivers 0.34%
Deep groundwater 11%
Shallow groundwater 12%
Less than 1% of water on Earth is available for human use

3. The Water Cycle
Water cycle – continuous process by which water moves through the living and non-living parts of the environment
In the water cycle, water moves from bodies of water, land, and living things on Earth’s surface to the atmosphere and back to Earth’s surface.

4. The process of the water cycle
Evaporation – the process by which molecules at the surface of a liquid absorb enough energy to change to the gaseous state.
Name three places that water evaporates from.
Transpiration – the process of water being given off through leaves as water vapor.

5. Water Cycle continued
Clouds form – condensed droplets of water clump together around tiny dust particles in the air, forming clouds.
Precipitation – The water vapor in the clouds becomes so heavy that they fall back to Earth.
Name the 4 types of precipitation.

7. How do we use water? Agriculture – growing plants
Irrigation – the process of supplying water to areas of land to make them suitable for growing crops.
Industry – industries use water in many different ways
Transportation – oceans and rivers are used fore transportation
Recreation – swimming, boating, skiing, snowboarding, skating

8. How do we use water?
List an agricultural use, and industrial use, and a household use of water that you relied on today.

9. Water and living things
Water makes up nearly 2/3 of your body
Water is necessary to keep your body functioning
Water is essential for living things to grow, reproduce, and carry out other important processes.
Photosynthesis – plants use water, plus carbon dioxide and energy from the sun, to make food

10. Questions What is the water cycle?
Where is most of the fresh water on Earth found?
How does the water cycle renew Earth’s supply of fresh water?

11. Water on the Surface – Section 2
River system – a river and all of its tributaries together make up a river system
Tributary – smaller streams and rivers that feed into a main river
Watershed – the land area that supplies water to a river system. Watersheds are also called drainage basins.
A river can flow into another larger river. When rivers join another river system, the areas they drain become part of the largest river’s watershed.

12. River systems
Divides – One watershed is separated from another by a ridge of land called a divide.
Streams on each side of the divide flow in different directions.
What is the longest divide in North America?

13. Rivers and Floods
Floods occur when the volume of water in a river increases so much that the river overflows it’s channel.

14. Can floods be controlled?
Building dams is one method of flood control.
Dam – a barrier across a river that may redirect the flow of a river to other channels or store water in an artificial lake.
Name a large artificial lake around here that was created when a dam was built.

15. Levees
Sediment deposits can build a natural defense against floods. As a river overflows onto its flood plain, it slows down and deposits heavier sediment alongside the channel. Over time these deposits build up into long ridges called levees.

16. Bodies of Fresh Water
Water in streams and rivers is always on the move
Water in lakes and ponds is still, or standing water
Ponds are smaller and shallower than lakes
Sunlight usually reaches to the bottom of all parts of a pond.
Most lakes have parts were the water is too deep for sunlight to reach the bottom

17. Ponds and Lakes
Ponds and lakes form when water collects in hollows and low-lying areas of land.
Both are supplied by melting snow and ice and runoff
Some are fed by rivers or ground water
Some ponds only appear in the spring and are created by runoff
Why can plants grow throughout a pond?

18. Ponds and Lakes
The bottom of a pond is usually covered with mud and algae
The bottom of a lake consists of sand, pebbles or rock

19. Lakes Lakes are created by
A cutoff river meander – oxbow lake
Ice sheets that melted at the end of the Ice Age
Movement of Earth’s crust
Erupting volcano
Building a dam
Reservoir – a lake that stores water for human use

20. Changes in a Lake
As the water heats and cools the layers of water mix, as the water mixes, minerals, plant matter, and other nutrients rise from the lake bottom to the surface. This lake turnover refreshes the supply of nutrients throughout the lake.
Eutrophication occurs when the nutrients build up in the lake and cause more algae to grow. This causes thick green scum on the surface of the water. As the algae gets thicker and blocks out more sunlight, the animals in the lake can not survive. The Lake will eventually dry up and be only plants.

22. Glaciers and Icebergs
Glacier – any large mass of ice that moves slowly over land, 76% of fresh water on Earth
Iceberg – When a glacier reaches the seacoast, icebergs form
Icebergs break into chunks as big as houses as they drift south
They begin to melt in warmer water
90% of an iceberg lies below the surface of the water. Only 10% is visible

23. Questions What bodies of water make up a river system?
Explain how ponds and lakes form.
Where do icebergs form