Electrical and Natural Gas Safety World Teacher's Guide
Page 8: Lightning
Objective: For students to understand that high-voltage shock can come from lightning as well as wires, and to learn how to avoid a lightning strike.
Background/Discussion: What is lightning? Electrical charges develop inside a storm cloud. Positively charged atoms go to the top of the cloud. Negatively charged atoms go to the middle or bottom. If the negatively charged atoms become too crowded, they jump to another part of the cloud, to a different cloud, or to the ground. This jump causes a huge spark of static electricity known as lightning.
In the U.S. each year, about 100 people are killed by lightning strikes and more than 1,000 are injured. Carissa was quite lucky. Most people who survive lightning strikes have much worse and longer-lasting injuries than Carissa’s. Ask students: Have you ever been on a golf course, sports field, or near water when a storm was approaching? What did you do? If you stayed outdoors, did you realize that you risked being struck by lightning?
Emphasize to students that if a storm is approaching or under way, they must immediately follow these precautions: Get indoors. Stay away from windows. Lightning can travel through plumbing pipes and electrical and telephone wiring, so stay away from tubs, sinks, anything electrical, and corded phones.
What Do You Think? The electricity from one lightning bolt could light up 250,000 homes. (30,000,000 volts/120 volts = 250,000)
Follow-up: Have students make a list of safe and unsafe places to be during an electrical storm.
• Safe places: inside a large, permanent building; inside a hardtop vehicle.
• Unsafe places: near metal or water, under trees, on hills, near electrical equipment including computers, corded phones, and TVs.
Page 9: Shocking Scene
Objective: To counteract a misleading movie scene, and to teach students to never contact or throw anything at power lines.
Background/Discussion: Electricity always takes the easiest path to the ground. It will stay in a circuit unless it can find a path to the ground. If you touch a circuit and the ground at the same time, you can become electricity’s easiest path to the ground. Electricity can flow through water, and because your body is 70% water, electricity can flow through you!
Emphasize to students that if they touch a power line while standing on a ladder or a roof, electricity would travel through them. And if their kite or balloon got tangled in a power line and they touched the string, electricity could travel down the string and into them on its way to the ground. Both situations would mean a serious (and possibly fatal) electric shock!
Now that students know a little about electrical safety, they can notice electrical safety errors in movies, books, TV shows, etc. Ask students if they have seen examples of people doing unsafe things around electricity in movies or TV programs. Did the person get an electric shock? Encourage students to write up their examples and/or do an oral presentation.
What Do You Think? Electricity doesn’t travel down metal utility poles because specially designed insulators hold the electrical wires away from the poles. That’s why it’s so important to never shoot at or throw things at insulators. If they break, electric wires can touch the utility pole and travel down it to the ground.