1. Unit 3 Nature’s Energy 1

2. 4. Water Energy

3. Moving water can push on objects and move them
Remember that any matter
that is moving is using
mechanical energy

4. This is called water energy
So water is a source of
mechanical energy
This is called water energy

5. Energy that comes from the push of water
Vocabulary
Water energy
Energy that comes from the push of water

6. A long time ago, people learned to use water energy for waterwheels
Waterwheels are built on streams

7. A waterwheel is a large wheel with blades on it
As water pushes on the blades,
the wheel turns

8. Even today, energy from waterwheels is used to grind grain and
to cut logs

9. 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

10. Dams hold back a great amount of water
This water is sent through pipes to
water turbines hundreds of feet below.

11. A device that turns water energy into mechanical energy
Vocabulary
Water turbine
A device that turns water energy into mechanical energy

12. A turbine is like a waterwheel, but it turns much faster
The falling water turns the turbines

13. The water energy that the turbines collect is used to run a generator

14. A device that makes electricity by electromagnetic induction
Vocabulary
generator
A device that makes electricity by 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

16. Water is a good source of energy
It does not pollute the air

17. But water power plants can be built only near a waterfall or a dam
It will never run out
But water power plants can be built
only near a waterfall or a dam

18. dams cost a great deal of money to build
Also,
dams cost a great deal of money
to build
All energy cannot come from
water energy