Good Morning n Take out your homework packet

Good Morning! n Take out your homework packet Turn to 17. 4 practice (P = I x V) n We will go over answers as a class n

Wednesday, May 13, 2015 n Learning Target: I can assess what I need to study before my test on Friday. n Today: n Go over answers to homework packet n Turn in! Work time on Review Packet n *Practice Test/Review tomorrow!! n

Warm Up n What is magnetic declination? n Draw a sketch of the Earth: Where is the geographic south pole? n Where is the magnetic south pole? n

Work Time n Goals: Turn in Homework Packet n Get majority of Review Packet finished n Improve class test average! –we’re a team! n n Tomorrow: Review packet should be done n Practice test/assess where we are at! n

Exit Question a. Your cell phone charger uses 8 amps of current when plugged into a 120 volt outlet. What is the power rating of the toaster in watts? b. What is the power rating in kilowatts? c. How many kilowatt-hours does your charger use if you use it for 14 hours a month? d. The utility company charges $0. 12 per kilowatt-hour. What does it cost you to use the charger for that month?

Warm Up n At which point(s) (A, B, C, or D) could the SOUTH pole of a magnet be placed in order to make the rotor spin counter clockwise?

Warm Up n Which way is the north pole in the electromagnet below? n Which way will the north end of a needle on your compass point?

Chapter 17 17. 4 Generating Electricity

Generating Electricity n Lots of heat energy is generated from coal, gas, and oil n Most of the heat energy is “lost” as unusable energy

Generating Electricity n n Nonrenewable resources: not replaced as it is used (ex: coal, oil, natural gas) Renewable resources: a natural resource that can be replaced (ex: falling water, Sun, wind)

Electricity from Fossil Fuels n n Take a long time to form! Three major fossil fuels: coal, oil, natural gas

Better(? ) Forms of Energy Nuclear Energy n Wind Energy (renewable) n Solar Energy (renewable) n Hydroelectric [water] Energy (renewable) n Geothermal Energy (renewable) n Biomass Energy (renewable) n

Electricity from Nuclear Energy n Nuclear energy does not pollute the air like fossil fuel power plants do.

Electricity from Nuclear Energy n Disadvantage = storage of nuclear waste n Uranium fuel from the reactor stays dangerously radioactive for a long time.

Renewable: Wind Energy n n 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.

Renewable: Solar Energy n n A solar cell (also known as a photovoltaic cell) can convert solar energy to electricity. The Sun’s energy is often called solar energy.

Renewable: Hydroelectric Power Hoover Dam n A hydroelectric (or hydropower) plant uses energy from falling water to generate electricity.

Renewable: Geothermal Energy n n 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.

Renewable: Biomass Energy n n 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.

Quick Check! 1. 2. 3. List 3 fossil fuels. Are fossil fuels nonrenewable or renewable? EXPLAIN. List 3 renewable resources.

Electrical Power n Electrical power: the rate at which electrical energy is changed into other forms of energy such as heat, sound, or light. n Electrical power is measured in watts, just like mechanical power. Power = current x voltage P=IV

Electrical Power n n Utility companies charge customers for the number of kilowatt-hours (k. Wh) used each month. A kilowatt-hour is a unit of energy, not power # of kilowatt-hours = # of kilowatts x hours

Electrical Power Example a. A toaster uses 12 amps of current when plugged into a 120 volt outlet. What is the power rating of the toaster in watts? b. What is the power rating in kilowatts? c. How many kilowatt-hours does the toaster use if you use it for 2. 5 hours a month? d. The utility company charges $0. 15 per kilowatt-hour. What does it cost you to use the toaster for that month?

Electrical Power Example a. A microwave uses 2 amps of current when plugged into a 80 volt outlet. What is the power rating of the microwave in watts? b. What is the power rating in kilowatts? c. How many kilowatt-hours does the microwave use if you use it for 8. 2 hours a month? d. The utility company charges $0. 25 per kilowatt-hour. What does it cost you to use the microwave for that month?

Electrical Power Example a. A computer uses 5 amps of current when plugged into a 120 volt outlet. What is the power rating of the computer in watts? b. What is the power rating in kilowatts? c. How many kilowatt-hours does the computer use if you use it for 28 hours a month? d. The utility company charges $0. 12 per kilowatt-hour. What does it cost you to use the computer for that month?