Me: I want to offer you a business partnership. It’ll make us incalculably wealthy and save mankind from extinction as a result of global warfare over dwindling energy reserves.
Robert: I’m interested. I would love to save mankind.
Me: I recently bought a drinking duck from eBay. I’m not sure what it costs to manufacture, but it can’t be much: The retail price was $6.45, and that included shipping from China.
Robert:I have one!
Me: Excellent. As you know, it’s a duck-shaped hollow glass barbell with a plastic top hat, a butt feather, a felt head and a body filled with pink fluid, all balanced on a crossbar. Its head bobs up and down into a glass of water. Seven weeks ago, I started it bobbing, and it hasn’t stopped. The only energy I put into it was a single poke to start the process, plus I occasionally top off the water. I think you, as a scientist, see where I am going.
Robert: I think so! Keep going!
Me: I envision giant drinking ducks, colossuses on the scale of the Hoover Dam, standing over every lake, river and reservoir in America, generating enough power for every American to operate hair dryers, toasters and circular saws 24-7. With your pedigree and my ability to generate publicity, we attract investors and become international drinking duck tycoons.
Me: You have doubts. I can tell. But don’t worry, the patent has expired. We’re free to make them.
Robert: Unfortunately, the device won’t work on a huge scale. The duck is a heat pump. It works by evaporation, and with evaporation, you need more surface area but less size. Volume is bad. A duck the size of the Eiffel Tower is not going to drink.
Robert: But it would work small. And engineering is so sophisticated now it actually could harvest the energy duck by duck and convert the torque into power.
Robert: Let’s run some numbers! The glass tube is about five centimeters long and one in diameter. We measure the gravitational energy of fluid rising in a pipe by the formula E = 0.5 x rho x g x pi x (r x h)². Multiply that out, you get 20 millionths of a watt per duck.
Me: That’s not much.
Robert: It’s not. It would take 5 million ducks to generate as much energy as your body does sitting immobile in a chair. But so what? We’re just talking a lot of ducks. Means we need space. Texas has a lot of space.
Me: Where in Texas?
Robert: Oh, all of it. At roughly 150 ducks per square meter, we’d need to pave the state and cover it with ducks. But that would give us only one-20,000th of the space we’d need to power the U.S., so we’d just have to go vertical. Stack the ducks, 20,000 high, which would require a building the size of Texas, one mile high. It’d have to be structurally sound, because water weighs a lot and we’d need people in there to top off the water glasses.
Me: We could save money by eliminating the tail feathers and top hat.
Robert: Yes. They are nice but inessential.
Me: How many ducks would there be?
Robert: The number’s so high I couldn’t say it. I’d have to write it on a blackboard with exponents.
Me: Is it possible to build a building a mile high?
Robert: Absolutely not. Steel is not strong enough to withstand the weight. But we won’t tell our investors that!
Me: I do!
Robert B. Laughlin is the author of “Powering the Future.”