Friday Sprog Blogging: energy (part 1).

This week, the bath-night conversation turned to energy. If you prefer to listen to the sprogs, what with the splishing of the bathwater and their American accents, you can download the audio file. (Actually, owing to the length of the conversation, this week it’s just me and the younger Free-Ride offspring. Next week will feature my conversation with the elder Free-Ride offspring, with the younger chiming in at the end as younger siblings are wont to do.)
The transcript of our conversation is presented below.

Dr. Free-Ride: I wanted to talk today about energy.
Younger offspring: Energy?
Dr. Free-Ride: Energy. What do you know about energy?
Younger offspring: Energy? Well … not much.
Dr. Free-Ride: Well, that’s OK. What do you think you might know about energy?
Younger offspring: I don’t know.
Dr. Free-Ride: What questions do you have about energy, then? If you don’t know about it, you might —
Younger offspring: Where does it come from?
Dr. Free-Ride: Well, that’s a good question. So, you know about where some kinds of energy come from, right? So when we drive some place, you know where the energy for driving comes from, yeah?
Younger offspring: No.
Dr. Free-Ride: No? What do we have to do every so often?
Younger offspring: Gasoline?
Dr. Free-Ride: Gasoline! That’s right. Gasoline is one kind of energy source. And, um … well, you know, we use energy in the house, right? And what kind of things do we do that use energy?
Younger offspring: Mmmm …
Dr. Free-Ride: That we kind of bug you about sometimes if you forget —
Younger offspring: The lights?
Dr. Free-Ride: That’s right. So the lights take energy. What kind of — do you know what kind of energy makes the lights go?
Younger offspring: Umm … electronic energy?
Dr. Free-Ride: Electricity, that’s right! Electricity. And I don’t know if you remember … have we ever talked about what electrons are with you?
Younger offspring: No, but we did read Alice in Quantum Land.
Dr. Free-Ride: Well, so you know a little bit. Oh, and there’s some motto about energy, isn’t there?
Younger offspring: Yes.
Dr. Free-Ride: What’s the motto?
Younger offspring: Um, energy is mass, mass is energy.
Dr. Free-Ride: OK. That’s a cool slogan, but —
Younger offspring: Wait, what’s a motto?
Dr. Free-Ride: It’s like a saying.
Younger offspring: Well, that is a saying!
Dr. Free-Ride: Yeah, it is a saying. So, at the quantum level, you’re right, mass can be converted to energy and energy can be converted to mass. But, you know, for most of human history, no one had any idea what the quantum level even was. So people had to get energy other ways. Electricity is one kind of thing that we use, and gasoline is one other kind of thing we use. And, do you know what other kinds of … have you talked in school at all about —
Younger offspring: No.
Dr. Free-Ride: “No.” You don’t even let me finish the question, you know you haven’t talked about it. Alternative energy sources?
Younger offspring: That’s what I thought you were going to say. No.
Dr. Free-Ride: No, you haven’t? OK. Well, some very traditional energy sources — like, you build a fire. If you burn stuff, that releases energy. And, what’s one thing a fire does?
Younger offspring: It burns off gas?
Dr. Free-Ride: Yeah, it burns stuff. If you’re near a fire, how can you tell?
Younger offspring: Well, it’s hot.
Dr. Free-Ride: Exactly. So one thing a fire does, one thing that burning stuff does, is it releases heat, right? And heat’s a kind of energy. And actually, one of the ways we use energy is to heat the house. Yes, and the water got heated, too. Exactly. So, is fire the only way to make things warm?
Younger offspring: No.
Dr. Free-Ride: No? Well, what other things could make something warm?
Younger offspring: Energy.
Dr. Free-Ride: Sure, but let’s say you were on a camping trip and you were cold —
Younger offspring: A thermos?
Dr. Free-Ride: Well OK, a thermos keeps heat in. It doesn’t create heat out of nothing. But, I don’t know, let’s say you were canoeing, and —
Younger offspring: A thermos of hot water?
Dr. Free-Ride: No no no, let me do the set up and then you can answer the question. So let’s say you’re swimming, and your bathing suit is wet and you get out of the water and it’s kind of cold and you want to warm up, and you think, “Wow, it would be nice to stand by a fire or a heater, but there isn’t one.”
Younger offspring: A towel?
Dr. Free-Ride: Hmmm, a towel? I don’t know if the friction counts… But I’m thinking, what if it’s outdoors and it’s a bright sunny day? What else could warm you up.
Younger offspring: The sun.
Dr. Free-Ride: The sun! Have you ever heard of solar energy?
Younger offspring: Yes.
Dr. Free-Ride: Yes? Do you know what solar energy does?
Younger offspring: Gets energy from the sun?
Dr. Free-Ride: Right, it captures the energy from the sun, and there’s different ways you can use solar energy. A really easy way to use solar energy is to just set up your windows so that you capture the sun while the sun is shining, and it can warm up your house better than if your windows are facing so you don’t get a lot of sunlight when the sun is shining down. Um, there’s slightly more sneaky ways to capture the energy from the sun, where you can use the energy from the sun to heat water and do fancy things with turbines or whatever.
Younger offspring: What are turbines?
Dr. Free-Ride: Spinny things.
Younger offspring: Spinny what things?
Dr. Free-Ride: Spinny … well, you know like on windmills? The thing that spins around on a windmill? That’s a turbine. Hey, by the way, do you know that wind is another source of energy?
Younger offspring: No.
Dr. Free-Ride: Do you know that there’re some windy hills not too far from here where there are big, big windmills?
Younger offspring: And cows?
Dr. Free-Ride: Well, OK, there’s cows, sure.
Younger offspring: Yay, grazing cows!
Dr. Free-Ride: Yeah, they’re not really much of an alternate source of energy at this point. Although, there are some places where, if people are getting their energy by burning stuff, and there’s not a lot of firewood, do you know what they burn?
Younger offspring: No.
Dr. Free-Ride: Cow poop.
Younger offspring: Eww!
Dr. Free-Ride: Well hey, it’s what’s available, and if you need to boil your water and cook your food and heat your house, better to burn cow poop than to go cold and hungry and with water that needs disinfecting. Right?
Younger offspring: But cow poop has germs in it!
Dr. Free-Ride: You know what? I think the fire pretty much takes care of that. Burning it is not the same as cooking it and eating it. True?
Younger offspring: True.
Dr. Free-Ride: I mean, you probably wouldn’t want to eat gasoline, either.
Younger offspring: Yes.
Dr. Free-Ride: I mean, you definitely wouldn’t want to eat gasoline. It’s actually a poison.
Younger offspring: Oh, I didn’t know.
Dr. Free-Ride: So, you know what? There are some challenges with energy, aren’t there?
Younger offspring: Yes.
Dr. Free-Ride: First you have to know where to get it. And, did you know that some of the kinds of energy we use aren’t necessarily so good for the environment if we use too much?
Younger offspring: Yeah.
Dr. Free-Ride: What do you know about that?
Younger offspring: Well, I know that it’s bad for the earth when you turn on the light and leave it on too long.
Dr. Free-Ride: Mmm hmm, that’s true. That’s why we say, if you’re not in the room —
Younger offspring: Turn off the light.
Dr. Free-Ride: And also if you’re in a room but it’s bright and sunny outside —
Younger offspring: Turn off the light!
Dr. Free-Ride: Yep.
Younger offspring: Happy ending.