Apparatus to focus human body heat for the purposes of cooking potatoes, 1930

I wonder if the "scientists" in this Feb, 1930 Modern Mechanix article ever actually built the potato-cooking apparatus shown here, or whether it was purely for illustration purposes.

SCIENTISTS have learned that our bodies are living machines of the combustion type in which the burning of fuel (food) is accompanied by the consumption of oxygen, liberation of heat energy and production of carbon dioxide as is the case in all combustion engines. Scientists find that the heat from a single person, if properly focussed, would be sufficient to cook potatoes.

Your Body Heat Is Sufficient to Cook Pan of Potatoes (Feb, 1930)


  1. Magazines like this were full of illustrations of devices that were ludicrous bullshit. Flying machines powered by screw-like propellers, helicopter backpacks, hand-held televisions . . . oh, wait.

    * * *
    After looking at the actual article, I don’t think the device shown above is a human-powered spud-singer. It is some kind of respiration-measuring device, perhaps for determining O2 consumption and CO2 output.

    1. I read Popular Science in the 70s.  It seemed that every third issue featured an article about the “Wankel rotary engine” and how it was going to revolutionize the automotive industry.  Pity about that.  

        1. “Not counting its peripheral hardware, the E-Tron’s range extender is a 9.4-inch-diameter by 9.8-inch-long cylinder.”

          Dude, you have a big fist.

  2. Reminds me of Robert Silverberg’s The World Inside.  The urbmon’s (Urban Monads are hundreds of stories high housing hundreds of thousands whose body heat warms the building. Night walking anyone?

  3. As I understand it, a typical human energy output is in the 100 Watt range. So we’re talking maybe Easy-Bake Oven kinds of cooking projects, if you could even transport the heat rather than just overheating the person.

    1. Hey, isn’t this pretty much the premise of The Matrix? Minus the potatoes.

      It’s the premise of Pink Flamingos, when Divine steals a steak by sticking it up her skirt and says later, “I warmed it up when I was downtown today in my own little oven!”

  4. a couch potato cooking “couch potatoes”, and I’m trying NOT to think about an accessory to add some hot-air “steam”

  5. If we could just focus energy like the article suggests, we’d all be rich. It’s hard to get a small quantity of high temperature heat from a larger quantity of lower-temperature heat.

  6. my grandfather was saved by potatoes. 

    During the 2nd world war, he was sent from Czechoslovakia to work in the post office in Berlin.  There was an air raid at one point when he was in the middle of cooking potato dumplings at his dorm. and he was unwilling to  leave them – thinking someone might eat them.  So while the others went to the bomb shelter he stayed behind.  Unfortunately the bomb shelter was hit and a number of people were killed but he was saved because he didn’t leave his potatoes. 

    1. Always have your potato with you and no harm will come to you. I wonder how many people know where I got that from.

  7. anytime we see something like: “heat … if properly focussed [sic]” we should stroke our beards, cluck our tongues, and wonder what is to be done with the second law of thermodynamics

  8. I’m imagining a race of “potato vampires” that steal the heat from their victims, leaving an icy corpse behind, and strolling nonchalantly down the street eating a foil-wrapped baked potato.  

  9. I guess, if by “cook” you mean “your potatoes will be ready next month.”

    The human body produces heat about equivalent to a 40 watt incandescent bulb. That’s wimpier than an Easy Bake oven.

    1. I have heard that it is more like a 100 watt bulb. I was in a building in Switzerland that utilized the heat generated in crowded rooms to heat other parts of the building. It  had a sophisticated heat transfer system and lots of insulation to use heat generated from diverse sources including human heat output. 

      1. It varies considerably depending whether you’re just sitting there (~40) up to doing a strenuous workout (~200). Even so, 100 watts would be equal to an Easy Bake so the potatoes still aren’t going to be done any time soon. Bulb men are additive so, for example, a 100,000 person sports arena is a 10 million watt bulb and is going to need some serious heat redistribution.

  10. The machine pictured doesn’t cook potatoes, but rather measures the oxygen consumption of the wearer, for purposes of estimating the total heat production of the human body. The original source explains more fully:

  11. If you hook up more people to the machine would the potatoes cook faster. And what about using horses or cows for even more rapid cooking time. Their manure could be used in the potato fields….

    1. A wick effect burn of a human body could easily boil several pots of potatoes . I think all supposed cases of SHC have been wick effect burns. There is some speculation that phosphane/phosphine gas may form in the intestines under unusual conditions, and cause true SHC, but it is unknown whether this has ever happened.

      BTW, at full exertion a trained athlete can put out a few hundred watts. Probably not enough to boil a sufficient amount of water in the time the athlete could put out that much power.  Still have the focusing problem too.

      Baking a potato with its own electrical resistance would probably be the most efficient way.  Sprint cyclists operating in shifts could bake a potato in about forty minutes.

  12. I think you’d be better off using a potato to heat a person. 

    Not in terms of efficiency or how many potatoes you’d need, but at least it could be marginally useful in some scenario where you’re cold and surrounded by potatoes.

  13. I think “properly focussed” heat means that they are using a heat pump to move the thermal energy and increase the temperature to a level suitable for cooking . A heat pump needs energy to drive it but together with the heat from the victim it can be several times more effective that using the energy alone to heat the spuds.

  14. This is one of my biggest pet peeves. The “Scientists have learned that our bodies are living machines.” NO! Our bodies are not machines, they are organisms. There is much value in observing our bodies and minds as if they were machines. There is also much value in trying to understand the ways we differ from machines.

  15. BTW, the standard estimate for figuring HVAC needs is that each human puts out about 100 watts of heat. (Doubled when you have a bright idea and a 100-watt lightbulb appears over your head, I suppose.)

  16. So scientists discovered the meaning of life, the purpose of our existence, back in 1930? No one ever told me it was all about potatoes…but it makes so much sense now.

  17. Why hasn’t this important exception to the law of thermodynamics been applied to more important applications?

  18. I actually used one of these once to cook some potatoes.  But when I was done I felt too cold and didn’t feel like eating potatoes anymore.

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