Your Renewable Energy World Teacher's Guide
Page 5: Which Circuits Will Work?
Objective: To teach the characteristics of an electrical circuit.
Background/Discussion: This lesson supports physical science content standards for electrical circuits. Electricity in circuits can produce light, heat, sound, and magnetic effects. Electrical circuits require a complete loop through which an electrical current can pass. They provide a means of transferring energy when heat, light, sound, and chemical changes are produced.
Before doing the activity, introduce the concept of a circuit. Explain that a circuit is a closed path, or a continuous loop. For electricity to flow, it must travel on a circuit of wires. The electricity in your school or home flows in a circuit. It goes from the power outlet to the appliance along one wire inside the appliance cord, and back from the appliance to the outlet on the other wire inside the cord. Electricity on power lines also flows in a circuit. It flows out from the power plant or substation on one power line and back on another.
Scientific Inquiry: In this activity, energy is delivered from the sun to a solar panel that, if the sun is shining and the wires are hooked up correctly in a closed circuit, will light the bulb.
A.
The light bulb will light because the sun is sending energy to the panel, which in turns sends the energy through the closed circuit connected to the bulb.
B.
The bulb will not light because the heat of the sun is obscured by a cloud. Thus, although the circuit is closed, there is no energy flowing through it.
C.
The bulb will not light because the circuit is open. The red wire is not connected to the bulb, so although the wire is receiving energy from the panel, it will not get to the bulb.
D.
The bulb will not light because the circuit is open. The red wire is not connected to the panel. No energy flows into the wire, so it will not light the bulb.
Page 6: Why Do We Need Renewable Energy?
Objective: To explain how energy is produced from fossil fuels and nuclear power, and why these nonrenewable resources cannot be relied on exclusively to provide all our energy in the future.
Background/Discussion: Coal, oil, and natural gas are burned to heat water into steam, which is pressurized and used to turn a turbine. These resources are called fossil fuels because they were formed when plants and tiny sea creatures were buried by sand and rock, then decomposed, and turned into fossil fuels. The processes that created them are no longer occurring, so fossil fuels are nonrenewable. In recent decades humans have been using fossil fuels at an increasingly faster rate, and it is getting harder to locate and bring them up through mines and wells.
Nuclear power is used to create heat that then converts water into steam, which turns a turbine. This process involves a machine called a nuclear reactor, which uses fuel rods containing uranium placed next to each other. The reactor causes the uranium atoms to split and as a result, a tremendous amount of heat is released. Uranium must be mined from the ground and, like fossil fuels, its supplies are finite and nonrenewable. Most nuclear waste is low-level radioactive waste, consisting of ordinary tools, protective clothing, and other items that come in contact with radioactive dust or particles. This waste and the highly radioactive spent fuel rods must be specially stored and disposed of so they do not harm living things or contaminate the environment.
Ask students to brainstorm how life would be different without the traditional energy sources that electrify our buildings and power our transportation. Before having them look at the conservation tips on the back cover, ask if any of them try to save energy at home, and make a list on the board of what practices they engage in. Explain that energy conservation and using renewable energy are the best ways to help reduce our dependence on nonrenewable energy resources.