Think this sounds too good to be true? Well, this was in UPI and they're one of the most important journalism resources on the planet so I assumed people who know physics a lot better than I do had figured out how to make something last for four hours using nothing but gravity.

Turns out I should rely less on pedigree and more on instinct. It's not real.

Sure, it's part of an interesting Master's thesis and it won a prize but no one has ever ever built it. Nor is it likely any time soon.

Looking at the schematic for the Gravia shows that the falling weight is defined as fifty pounds, which is 22.7 kilos, which is indeed about as much as a variety of humans could reasonably be expected to be able to lift back to the top of the tube every few hours.

22.7 kilograms falling 1.22m in gravity of 9.8 metres per second squared gives you a grand total of 271.4 joules.

That, once again ignoring losses (which are likely to be considerable, seeing as there’s a ball-screw and an electrical generator in the Gravia), will by definition run a one-watt lamp for 271.4 seconds, or four and a half minutes.

If you downgrade the lamp to one tiny 0.1-watt LED night-light, you get three-quarters of an hour.

So not even an LED nightlight for 45 minutes with 50 lbs. of weight? Yikes. I feel sort of stupid for putting this in a dusty corner of my blog but I can't feel as dumb as UPI for sending this all over the world.

I certainly am not saying he doesn't deserve his $1,000 prize. Anyone dumb enough to give him that prize without seeing it work deserves to be bilked out of the money, or he deserves some kind of Nobel Prize for bluffing them ("Ummmm, evil Big Oil heard about it and bought it on the way over so they could hide it and wreck the planet"), it just means I won't be endorsing the EnerJar that won first place any time soon.