1. Chapter 15 Section 3 What are our main energy sources?
Objective:
Name and describe the main sources of energy.

2. Fossil Fuels Fossil Fuels are the world’s main energy source.
Oil, coal, and natural gas are fossil fuels.
Fossil fuels can generate electricity and heat.
They can also run car engines and other types of machinery.

4. Fossil Fuels
However, most of our current energy sources have problems associated with them.
Fossil fuels are rapidly being used up.
Their use can also harm the environment.

5. Fossil Fuels
People need to find ways to cut down on the use of fossil fuels.
Some ways to do this include using energy-efficient cars, carpooling, lowering the heat, and turning off unneeded lights.

6. What are three fossil fuels?
NAME:
What are three fossil fuels?

7. Hydroelectric Power
Water stored behind a dam has potential energy.
When the water flows downhill, its stored potential energy changes to the energy of motion, which is called kinetic energy.

8. Hydroelectric Power
The electrical energy power plants produce from running water is call hydroelectric power.
At hydroelectric power plants, the moving water turns the blades of a machine that is called a turbine.
The turbine drives an electric generator that produces electricity.

9. Hydroelectric Power
Today, falling water is used to produce about 20 percent of the world’s electricity.
Hydroelectric power does not pollute the air.
Also, its energy source, moving water, is renewable.
However, dams can affect the wildlife living on or near a river by changing the environment.
Dams can also alter the natural flow of rivers.

10. 2. DESCRIBE:
What are two advantages of hydroelectric power plants?

11. Nuclear Power Energy produced by splitting atoms is nuclear energy.
The heat given off when atoms split can be used to produce steam.
The steam powers generators to make electricity.
Uranium is commonly used as fuel.

12. Nuclear Power There are drawbacks to using nuclear energy.
Deadly radiation is produced in nuclear reactors.
An accident could release this radiation.
Also, a way must be found to safely store the wastes, which remain deadly for thousands of years.

13. Nuclear Energy
Energy can also be released by combining atoms.
However, this kind of nuclear energy is very difficult and costly to produce.

14. 3. IDENTIFY:
What are some problems with using nuclear energy?

15. Classwork CHECKING CONCEPTS
What is the most commonly used fossil fuel?
How can you produce electricity from moving water?
What kind of energy does a dam store?
How is nuclear energy produced commercially?

16. Classwork THINKING CRITICALLY
5. HYPOTHESIZE: How might building a dam affect the living things in an area? Give an example.
6. CLASSIFY: Classify each of the following items as having potential or kinetic energy:
a. a book on a shelf b. milk in a bottle
c. a book falling to the floor d. a parked car
e. juice being poured f. a moving car