## In the Classroom

Course: “Energy”

Instructor: Larry Hunter, Stone Professor of Natural Sciences

Class size: 20

Listed in: Physics

There’s solar, wind and hydro. Nuclear, biomass and geothermal. Coal, oil and natural gas. With so many energy options, it’s hard for the average homeowner—or undergraduate—to make sense of it all. Hunter teaches a course for non-science majors that explores the physics of energy, and he also practices what he preaches, bicycling to work and heating his home’s water through solar panels. Here, he answers questions about the course.

Interview by Caroline J. Hanna

Q    What experiments do you assign?
A     The first lab is the least expensive lab I have ever done with students. All it requires is a paint bucket and a \$2 thermometer. I ask them to calculate the amount of energy used to heat their shower. Then I ask them to calculate how long they would have to ride an exercise bicycle in order to heat up the water. Typically, you’d have to ride your bicycle about 24 hours a day just to heat your shower. We compare that to how much it would cost to purchase electricity to heat that hot water—about \$0.35, which gives you a sense of what a bargain energy is and why we have gotten so free with using it.

Q    Have your own attitudes changed since you started teaching the course?
A     At first I thought ethanol was a pretty good idea. But after we looked into that, it was apparent the whole thing was a boondoggle. It’s not clear that you burn any less nonrenewable fuel, especially when you’re using corn. The amount of energy that goes into growing corn is at least comparable to or even more than the amount of energy we get out of the ethanol.

Q    I see you’ve got a battery under your desk.
A     This battery is being charged by the sun. About 2.8 amps are flowing down to it from a solar panel on the roof. There are five panels on top of Merrill [Science Center]. Four provide Merrill with a little bit of energy. It’s a pathetic amount—probably enough to keep my office lit. Anyway, I can use this battery to run my computer or the projector I use in class.

Image © 2011 Keith Negely c/o the ispot.com

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