You know when I started really getting into science? It’s when a high school chemistry teacher chucked a big chunk of the curriculum and taught us practical math instead: how to use the power of estimation to get ballpark estimates of various phenomena. It really woke me up to the power of simple arithmetic and reason.
So here’s a really good example. A couple of people have been raising money to build a gravity powered lamp Just raise a bag full of dirt and let it slowly drop, and the power generated will drive a small reading light, or can be used to recharge batteries, they claim. It’s the same principle that drove my grandparents’ cuckoo clock; every morning they’d pull a chain to raise the weights, and over the course of the day they’d slowly descend, making the whole mechanism tick.
Which immediately made me suspicious — that’s all that pound or two of counterweights did, was make a precisely designed and balanced delicate clock mechanism work. You can really get that much energy, to generate a useable amount of light, with such a trivial amount of input? And then I saw the video, where they raise the weight and the light instantly comes on brightly, with no detectable descent of the weight. This can’t be true, I thought.
But then I read this site, where they whip out the metaphorical envelope and scribble some quick calculations, that same estimation technique my high school teacher showed us how to use. Nope, can’t work. None of the numbers make any sense.
They also highlight one of the creator’s comments:
With hand-cranked devices, it might require three minutes of turning a handle for half-an-hour’s return. With this amount of effort required from the consumer, it’s often not seen as a particularly attractive trade-off. The GravityLight just needs three seconds of lifting for 30 minutes’ return.
Think about that. Somehow, a quick lift of a 10kg weight is now energetically equivalent to three minutes of hard exertion. It does not compute.
I suspect their demo unit has a nice little slot for a 9V battery. And for that they’ve received $280,000. Now that’s the kind of return from input that really violates the laws of nature.
OK, I’m going to back off on the implication of fraud. The commenters say that it would produce some minuscule amount of light; the question is whether it would be sufficient to be at all useful. It’s possible their only crime is exaggeration.