Ain’t no genie in this magic lamp
What better treatment for a prize-winning gravity-driven lamp concept than a take-down-and-send-up? Daniel Rutter, an Australian journalist and blogger, is the author of this cutting use of elementary physics to debunk a patent-pending floor lamp designed by a Virginia Tech masters student (!). It won the second prize in a green gadget competition (!!).
A sample of Rutter’s observations:
It’s a funky looking thing, which was widely reported around the gadget blogs, and was alleged by its designer, Clay Moulton, to give the equivalent light output of a 40-watt incandescent bulb for four hours from the energy of a weight dropping about four feet, or 122cm. When the weight gets to the bottom, you just lift it back to the top and away you go again.
Now, it stands to reason that a mere 1.2-metre drop isn’t going to give you forty actual watts for four hours unless the weight is incredibly heavy. Ignoring losses, it would by definition take forty watts of power over another four hours to lift the weight back up again, which is 160 watt-hours, which is quite a lot. A normal adult human in reasonable shape can manage about 75 watts of output when pedalling away on a bike connected to a generator; it’d take more than two hours of such pedalling to raise that weight back to the top of the Gravia light’s tube, if the weight were heavy enough to make a constant 40 watts on the way back down.
So I just assumed the lamp’s brightness was greatly overstated, and wasn’t even four-watts-of-LEDs-that-are-sort-of-equivalent-to-forty-watts-of-incandescent. But since they’d clearly actually made the thing and it’d won an award, I presumed it did work, if only as a night-light. Fair enough.
But neither Clay Moulton nor anybody else has, actually, built a Gravia. The damn thing doesn’t exist.
[…]
The original press release about the Gravia on the Virginia Tech site now also contains a disclaimer from Moulton, though without any mention of him giving back the prize. I think it’s worth mentioning one line he uses on both pages, though: “I was told it was not possible given current LED’s, but given the rapid pace of innovation in low powered lighting, it would be a conceptual challenge.”
Yes, Mr Moulton, it certainly bloody would be a “conceptual challenge” to make a lamp that produces more than thirty times as much light as the laws of physics say is possible from the energy you put into it. That would be a pretty damn impressive achievement. I propose Virginia Tech not permit you to graduate until you do it. How’s that grab you?
Ouch. Let’s see what the US Patent and Trademark Office makes of this thing. Bet they issue a patent.
(Hat tip: Kriek Jooste.)
