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

Pretty radiometer that arrived safely despite its fragile appearance.

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 media could not be loaded.  I bought this as a gift for a relative who put it in her sunny kitchen window. It was much appreciated.Well made, fun, and a good science visualization for young and old.I bought another this year for my wife. It’s fun to watch. On a sunny day it FLIES!

It's attractive and works sufficiently well to help kids understand some basic principles of science. Just make sure you've updated your understanding of how it works because this has evolved over the years.

Looks great in my great room window sill. Spins beautifully when the sun hits it. Perfect little unique accent.

we purchased a more expensive radiometer that was not as good. this one is very sensitive and if there is any light it will turn slowly. and when fully sun it's spinning like crazy. great size. really fun.

Looks even better than the pictures. Functions flawlessly and adds an elegant touch to any window ledge. It is a real conversation starter!

I wasn’t sure what I would think of this item. Honestly I didn’t know much about this instrument. Item arrived fast and on time. I thought it would ofBeen bigger in size but That’s ok. After placing the item where sun light was shining, the item started to spin and spin and spin faster. It goes pretty good. I must say it’s a pretty cool thing to have on your office desk or at home. If your into this sorta thing I am recommending this for you.

孫のプレゼントに購入しました、良く回ります。晴れた障子越しでもゆっくり回り、窓の柱の影でもゆっくり回りました、日差しがかかるとクルクル回ります。興味を持ってくれるといいですが。

It works well enough but it's very small.

明るい窓側に置けば良く回ってくれます。曇りでもある程度の明るさがあれば大丈夫です。明るくても蛍光灯やLED照明では回りません。ガラス製の製品でデザインも良くインテリアとして楽しめます。

just the coolest thing ever