Electrical and Natural Gas Safety World Teacher's Guide
Geothermal Energy: Comes from “geo” for earth, and “thermal” for heat. The hot molten rock inside the earth isn’t going away anytime soon, making geothermal energy RENEWABLE. Although it is renewable, geothermal energy has some limitations: people must be careful not to draw steam or hot water out of the earth faster than it can be replenished.
Solar Energy: The sun’s energy will never run out, so solar energy is RENEWABLE. It’s true that sometimes the sun isn’t shining, so photovoltaic cells cannot always make electricity. However, solar power systems can store electricity in batteries for non-sunny days.
Wind Power: The wind will be around as long as the earth is, so wind power is RENEWABLE.
Fuel Cells: Fuel cells run on hydrogen. If the hydrogen comes from a renewable resource like landfill gas, fuel cells are RENEWABLE. However, if it comes from a nonrenewable resource like fossil fuels, fuel cells are considered NONRENEWABLE
Follow-up: After students complete this activity, make a list on the chalkboard of renewable and nonrenewable fuels.
Page 5: Go with the Flow
Objective: To explain how electricity flows in a home electrical system.
Background/Discussion: This illustration does not show electricity’s complete circuit. Explain to students that electricity is generated in a power plant and sent out over transmission lines to a substation where the voltage, or pressure, is reduced. Then electricity flows through the overhead and underground distribution lines shown in the illustration, to homes and buildings. After it is used it flows back out into the power grid.
Find out how much your students know about electrical safety. Ask students to select three of the numbered locations on the drawing. Have them describe behavior that could put someone in contact with electricity at each location, and a safety tip or safe practice to prevent this. For example, for #10, the electrical outlet, a dangerous behavior would be to poke a sharp object into the outlet. A safety tip to prevent this would be “Put only plugs into outlets.”
Activity Answers: 1—Overhead power lines. 2—Underground power lines. 3—Transformer. (There are two transformers. The one on the left serves overhead power lines; the one on the right serves underground power lines.) 4—Service wires. 5—Electrical panel. 6—Circuit breakers. 7—Fuses. 8—Home wiring. 9—Switch. 10—Outlet. 11—Power cord.
12—Appliance.
Page 6: Which Bulbs Will Light?
Objective: To teach the characteristics of an electrical circuit.
Background/Discussion: Before doing the activity, introduce the concept of a closed path. Explain that a closed path is like a continuous loop, with no breaks or obstacles in it. Ask students to name some shapes that are closed paths, and some that are open. Some examples of closed paths are a circle, square, rectangle, and triangle. Examples of open paths are a spiral, a line, and a U-shape. For electricity to flow, it needs to travel in wires that are a closed path with no breaks or obstacles.
In this activity, the path goes between the negative side and the positive side of the battery. Electric current flows from the positive side of the battery to the light bulb and back to the negative side of the battery.
Answer Key:
Top Left: OPEN. The bottom wire touches the base of the lightbulb but the top wire does not. The top wire touches the top of the lightbulb, and because the glass of the lightbulb does not conduct electricity, it is an obstacle that prevents electricity from flowing along the wires.
Top Right: CLOSED. Bending the wire does not affect whether the circuit is open or closed.