Orange Solar Power Radiometer Crookes Solar Energy Spinning Vanes Windmill Gift Home Desk Decoration

The packaging for the radiometer was very adequate to get such a fragile device to me. It is glass and it has to maintain a partial vacuum inside to work properly so delivery was a concern.This Crooke's Radiometer was originally invented as a physics device and does what it was intended to do. It was intended to measure the power of the light incident on the vanes. Several people commented in reviews that it didn't spin in the light of their common lamp, and that is expected. It would take a strong directed household spot light to focus enough photons on the vanes.If you put the device in any full sunlight it should spin very fast. Normal sunlight is imparting much more energy than my house lamp. Thus sunlight is typically required to take advantage of this physics toy.I have another radiometer made of plastic which spins slower in the same sunlight. I believe this due to that plastic radiometer not passing as much light radiation to the vanes. The glass device passes more of the light. And probably has a better balance of vacuum. The vacuum inside has to have a partial atmosphere to work best.You'll note the spin direction shows the darker side of the vane paddles are pushed away from the light source, which confirms the principle that the absorption of energy and subsequent passing of heat energy to the air molecules inside the device is the cause of the spinning. It does not spin because of the impact of photons because if it did, the lighter side of the paddles would be pushed away and the device would spin in the opposite direction, as more photos would be reflected by the lighter side of the vane's paddles.

Got it yesterday, and yesterday we had a variety of weather, so here's my experience:1) In direct sunlight, it "whir spins". I don't mean it makes sound, but it's moving so fast it's just a blur.2) In indirect sunlight, but still a bright day: steady spin, but not real fast. Maybe one rotation every second or second and a half. But it keeps it up.3) Cloudy daylight: sits there like it's waiting for a bus. Maybe twitches a little occasionally, but no rotation whatsoever.So, there you have it. It actually works better than I had hoped, and so I give this a full five star thumbs up. The colored glass makes for an attractive piece, and I could see giving one of these to just about any science-minded person. The fact that it doesn't spin on a cloudy day is more than compensated for by its behavior in direct sunlight, where it spins so fast that in an earlier age you might have thought it was possessed by demons. You can think that now, too, if you want, but it probably isn't actually true.

The best science gift ever. I'm 70 and I still love them. I've had at least 4 over the years.

Looks like dirty fingerprints on the flags, the black side of the flags has chipped paint. The wheel requires full sun to turn. Poor quality control. A waste of money.

Good eye catcher

A gift for my grandson.

I bought this for my husband for our 11th anniversary and he absolutely loved it! He opened it at the restaurant where we booked for our anniversary lunch and it was a head-turner! Everyone there started to ask how it worked. It’s an eye-catcher on my husband’s mahogany desk. Very classy. A great gift for anyone who wants to ignite the imagination or inspire wonder.

Does not work at all. I would return it but I threw away the foam packing it came in. The box and foam packing were the best part of this purchase. Even too light to serve as a paper weight. I guess I will set it on a shelf so I can remind myself periodically how I can be screwed by an Amazon purchase.