11. 2 Water Energy Energy that comes from the push of water

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2

Water Energy

Energy that comes from the push of water

3

Moving water can push on objects

and move them

Remember that any matterthat is moving is using

mechanical energy

4

So water is a source ofmechanical energy

5

A long time ago,people learned to use

water energyfor waterwheels

6

Waterwheels are built on streams

7

A waterwheel is a large wheelwith blades on it

As water pushes on the blades,the wheel turns

8

Even today, energy from waterwheels is

usedto grind grain

andto cut logs

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When water falls from a high place

to a lower place,it carries a lot of energy

Dams are built on rivers and lakes

to make use of this energy

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Dams hold back a greatamount of water

This water is sent through pipes to

water turbineshundreds of feet below.

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Water Turbine

A device that turns water energyinto mechanical energy

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A turbine is like a waterwheel,but it turns much faster

The falling water turns the turbines

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The water energy that theturbines collect

is used to run a generator

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Generator

A device that makes electricityby electromagnetic

induction

15

A lot of electricity can be made by dams

Hoover Dam, on the border between Arizona and

Nevada,is one of the highest dams

in the world

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Water is a good source of energy

It does not pollute the air

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It will never run out

But water power plants can be built

only near a waterfall or a dam

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Also,dams cost a great deal of money

to build

All energy cannot come fromwater energy