I bought a Radiometer for Isaiah, ok, I got it for me too because they are cool. I wanted to show him how the sun can create energy in a very simple way. On our trip this summer, we went to my old high school and the superintendent had one in his office and Isaiah was amazed, so I figured for $10, why not. Well, I got it today and decided to play around with it a bit. First, I shot my green laser at the dark side of the panels, and low and behold, very slowly, it began to spin. Then I pulled out my Fenix PD20. Now I am no physicist, but I thought it was the heat from the light source that made the radiometer spin. As per the explanation on the box, when the light strikes the wings, it transfers heat to each one. The lighter one reflects the rays and the darker one absorbs the rays......when the atoms strike the dark vanes, they "kick" away at terrific seed. So with that in mind, I pointed my Fenix at the radiometer and that sucker took off. I know how bright the light is, but never thought it produced so much heat energy in the beam, but sure enough, it does. So, there is just another good reason to buy a Fenix PD20, it makes radiometers spin like crazy. Science is cool.
