Help to locate a
April 16, 2010 12:16 PM   Subscribe

I'm trying to find a particular solar-powered toy/gadget, which I saw a few years ago. It consisted of four very light blades within a glass bulb, spinning under the pressure of the sun on one side.

I think it had a particular name - perhaps named after a scientist who first built it - but it escapes me. I haven't managed to find it through Google, though I'm sure it must be out there somewhere. I'd love to buy it as a present for a friend, and I've tried many websites which sell similar gifts, but not the exact piece.
posted by tawny to Technology (12 answers total) 1 user marked this as a favorite
 
I think you are talking about a radiometer.
posted by FishBike at 12:17 PM on April 16, 2010


Been around for over a century now. Wiki link. Any decent science supply place should have them.
posted by Aquaman at 12:18 PM on April 16, 2010


ThinkGeek
posted by 543DoublePlay at 12:21 PM on April 16, 2010


What they said. Works based on heat convection tho.
posted by jdfan at 12:23 PM on April 16, 2010 [1 favorite]


They've enjoyed increased popularity recently due to the ready availability of cheap lasers. Try it!
posted by MrMoonPie at 12:32 PM on April 16, 2010


If there is a science museum in your area, you will almost certainly find them in the gift shop as well.
posted by jquinby at 1:05 PM on April 16, 2010


Warning: if you have a cat, and it can get to it, it will break it.
posted by StickyCarpet at 1:08 PM on April 16, 2010 [1 favorite]


Not convection. Photons are absorbed on the black side, reflected on the shiny side, causing rotation.
posted by Carmody'sPrize at 1:22 PM on April 16, 2010


I think it had a particular name - perhaps named after a scientist who first built it...

Crookes radiometer
Read the explanations for the force on the vanes. It is not as simple as it seems.
posted by weapons-grade pandemonium at 1:41 PM on April 16, 2010


Carmody'sPrize: That's the explanation that's commonly given, but it's completely wrong. For one thing, the direction of rotation is opposite to what it would predict, and for another, the effect disappears when all the air in the bulb is removed.
posted by teraflop at 8:02 PM on April 16, 2010


I got a radiometer as a kid from Edmund Scientific. Here's one, and a very fancy one.
posted by belau at 8:52 PM on April 16, 2010


Thank you all. Crookes Radiometer is exactly it. I like Metafilter.
posted by tawny at 5:18 AM on April 17, 2010


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