UNIT FIVE: Electricity and Magnetism

2. UNIT FIVE: Electricity and Magnetism • Chapter 16 Electricity • Chapter 17 Magnetism

4. Chapter Seventeen: Magnetism • 17.1 Properties of Magnets • 17.2 Electromagnets • 17.3 Electric Motors and Generators • 17.4 Generating Electricity

5. Chapter 17.4 Learning Goals • Review the meaning of mechanical power and liken it to electrical power. • Compare and contrast renewable and nonrenewable sources of electrical energy. • Discuss methods of electrical energy conservation.

6. 17.4 Generating Electricity • Electricity is made in a power plant. • Most power plants burn fossil fuels (natural resources like coal, oil, or natural gas) to produce heat.

7. 17.4 Generating Electricity • Next, this heat is used to boil water. • The steam from the boiling water turns a turbine. • The turbine turns a generator which produces electricity.

8. 17.4 Electricity from fossil fuels • A nonrenewable resource is not replaced as it is used. • Because it takes so long for these resources to form, someday we will not have enough fossil fuels to produce the electricity we need. • The three major fossil fuels are coal, oil, and natural gas.

10. The United States gets about 19% of its electricity production from nuclear power plants.

11. 17.4 Electricity from nuclear energy • The main advantage of using nuclear energy to produce electricity is that it doesn’t pollute the air like fossil fuel power plants do.

12. 17.4 Electricity from nuclear energy • Storage of nuclear waste has always been a major disadvantage of nuclear power plants. • Uranium fuel from the reactor stays dangerously radioactive for a long time.

13. 17.4 Electricity from renewable resources • A renewable resource can be replaced naturally in a relatively short period of time. • The Sun and wind are renewable resources that can be used as energy sources.

14. 17.4 Electricity from renewable resources • It is also possible to use: • moving water (hydroelectric) • hot spots near Earth’s surface (geothermal) • fuels made from once-living things like wood or corn (called biomass) or • tides to produce electricity.

15. 17.4 Hydroelectric power • A hydroelectric (or hydropower) plant uses energy from falling water to generate electricity.

16. 17.4 Geothermal and biomass • Geothermal power plants use Earth’s internal heat energy, in the form of water or steam, to produce electricity. • A geothermal heat pump system takes advantage of the relatively constant temperature of Earth’s shallow ground.

17. 17.4 Geothermal and biomass • Biomass is organic material from plants or animals. • In waste-to-energy plants, renewable solid waste is burned to produce electricity, which also creates some air pollution.

18. 17.4 Wind and solar energy • California was the first U.S. state to build large wind farms. • Wind farms can disturb natural habitats, and can perhaps scar a large area of scenery.

19. 17.4 Wind and solar energy • The Sun’s energy is often called solar energy. • A solar cell (also known as a photovoltaic cell) can convert solar energy to electricity.

20. 17.4 Electrical power • Electrical power is measured in watts, just like mechanical power. • Electrical power is the rate at which electrical energy is changed into other forms of energy such as heat, sound, or light.

21. 17.4 Electrical power • Utility companies charge customers for the number of kilowatt-hours (kWh) used each month. • A kilowatt-hour is a unit of energy. • The number of kilowatt-hours used equals the number of kilowatts multiplied by the number of hours the appliance was turned on.

22. 17.4 Electrical power • There are many simple things you can do to use less electricity. • When added up, these simple things can mean many dollars of savings each month.

24. Under the Sea • Have you ever wondered what it would be like to take a “walk” on the seafloor? Engineer Jim Varnum gets to go “down under” regularly, because he is a pilot of an extremely complex robot called Jason II. This robot dives deep into the ocean and is used to take pictures and collect data from the seafloor.