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

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

4. 4 So water is a source of mechanical energy

5. 5 A long time ago, people learned to use water energy for waterwheels

6. 6 Waterwheels are built on streams

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

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

9. 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. 10 Dams hold back a great amount of water This water is sent through pipes to water turbines hundreds of feet below.

11. 11 Water Turbine A device that turns water energy into mechanical energy

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

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

14. 14 Generator A device that makes electricity by electromagnetic induction

15. 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. 16 Water is a good source of energy It does not pollute the air

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

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