Delivering Power to the People

Display the slide that has an image of the digital readout of an exercise bicycle (along with a silhouette of someone exercising).

Paraphrase:

Notice that the stationary bike in the picture doesn't have a plug yet the display board seems to use electricity. Do you think that's just a mistake or is that really possible?

Allow students to discuss among themselves. Treat this as a brain teaser and let them know that, by the end of the activity, they will know.

Choose three students to read the parts of Hamza, Cooper, and Olivia. This scene is an informal introduction to the concepts of power and energy. The students discuss exercise bikes that are in the school’s gym.

Prior to reading, explain to students that they will be introduced to new vocabulary terms and ideas that may not be familiar. Reassure them that this lack of familiarity is okay. The reading is meant to introduce the ideas, not explain them completely.

Consider previewing the generator image before reading. Ask students what they think it is. Students may not be familiar with exercise bike displays or simple generators. Ask them where else there are generators (on a car). Ask what function they serve on a car (to generate or produce electricity to recharge the battery).

When Olivia tells Hamza that windmills generate electricity from spinning, you may want to pause to discuss this moment with students. If there is a nearby windmill farm, it may be helpful to refer to it during the reading. Also, ask students if they have seen lights on a bicycle that are lit up by a small wheel that spins on the bike wheel. (Bike light generators aren’t so common anymore!)

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Setting: Hamza and Cooper are sitting in the school cafeteria discussing some new equipment they saw in P.E. class the previous period. Olivia walks up and joins them.

Hamza: I hate them.

Cooper: I think they’re great! Perfect for me to work out for my triathlon.

Olivia: What are you guys arguing about?

Hamza: Those stupid exercise bikes they just put in the gym.

Olivia: So Hamza, you’re not into cardio fitness?

Hamza: P.E. is for sports! What does fitness have to do with it?

Cooper: Well, I think it has everything to do with it. The bikes are there to get more students into shape. Not everyone is into sports like you are.

Olivia: I haven’t seen this equipment yet. Is it new?

Cooper: Yeah, Coach Thompson said they were supposed to come in at the beginning of the year, but since she wanted the kind that doesn’t plug in, they took longer to get here from the factory, I guess.

Hamza: Wait, they have to plug in somehow. They need some way to get current. Didn’t you see that they have a digital readout and a place to charge your phone? That’s the only cool thing about them!

Cooper: That’s just it! The power it takes to light the display comes from spinning the pedals around.

Olivia: You mean there’s a generator inside the bike that turns motion into electricity?

Cooper: Right.

Hamza: That’s ridiculous. You can’t create electricity just by spinning something around.

Olivia: I have one word to say to you, Hamza...

Hamza: Yeah?

Olivia: Windmill.

Hamza: Oh, yeah.

Cooper: She so got you, dude.

Hamza: But a windmill is huge! Bike pedals can’t do what windmills do.

Olivia: True. Bike pedals can charge your phone and light up the display, but wind turbines can put out a megawatt. That’s enough to power 500 houses!

Hamza: Mega what?

Cooper: Watt. Not what.

Hamza: What?

Olivia and Cooper: WATT!

Cooper: You know what a watt is. Ms. Q went over that last week.

Hamza: Oh, watt! Like with light bulbs. Why didn’t you just say so? I remember that from when we made generators in science class. That was kind of fun.

Olivia: Right, and remember how Ms. Q wouldn’t tell us why we needed that cardboard tube from the toilet paper rolls?

Cooper: Hamza didn’t listen and brought a full roll to school! (They laugh.)

Hamza: I forgot about that part. I did get a lot of weird looks on the way to school that day.

Olivia: ANYWAY, so windmills have a bigger version of generators that transform kinetic wind energy to electrical energy.

Cooper: That’s like the transformation from the kinetic energy of pedaling to electrical energy on those COOL bikes that Hamza hates.

Hamza: Okay, I guess I don’t hate them... In fact, maybe if we sat on those bikes in all our classes instead of sitting at desks that we could supply power to the whole school.

Olivia: Hmmm.... Very cool idea, but do you really think we could sustain that long term? Seems like we’d get tired.

Cooper: We’d definitely have to fuel up with a good breakfast and the occasional energy bar. But I’m trying to picture myself learning algebra on a bike. I don’t know if I could concentrate.

Hamza: (more excited) But think of all the energy we would conserve! Plus, if we got solar cells and windmills on the roof we’d be like Rockin’ Renewable Middle School baby!

Olivia: Fun ideas, Ham, but I say we reduce our use of electricity instead of going crazy with all that stuff. We can start with light bulbs.

Hamza: Booooring!

Cooper: No, it’s true. We already have the technology to make more light using less electricity. They’re called energy-efficient lights. They cost more, but they last longer and use less power. Hamza, you might even be able to light one up with the watts you create pedaling one of those COOL new bikes in P.E.

Hamza: Not so cool.

Olivia and Cooper: Cool!

Hamza: Okay. Maybe a little cool.

You may wish to take some time to discuss some of the terms used in the scene.

Students may not understand the word transformation. Point out that in this context, it refers to changing from one type of energy to another.

Students can infer the meaning of sustain from the sentence (maintain or keep up). Synonyms include maintain, support, bear, endure, and uphold.

“Power” appears multiple times and is the focus of the rest of the Science Scene. Ask students for an informal definition and to use it in a sentence. However, don’t give a formal, scientific definition at this time.

Tell students that they are not expected to have a scientific definition of power, but to share what they think it means. The idea is that as they learn more, they will refine their definition of power.