11

2 Water Energy Energy that comes from the push of water

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

4 So water is a source of mechanical energy

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

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

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