toc1955's video: Homemade Crookes Radiometer

(Adolf Cortel, February 2012) [ if interested in Crookes Radiometers have a look at my improved double one: https://www.youtube.com/watch?v=Mm5scaMbR34 ] A Crookes radiometer is build with a vacuum can, a two stage vacuum pump and the rotor from a broken commercial Crookes radiometer. With a pressure low enough an IR bulb makes the radiometer rotate, The optimal pressure of this gadget depends on the size of the rotor and for the commercial ones is in the 1-0.1 Pa range (around 7 to 0.7mtor). The pump used in the experiment is able to reach 30 mtorr, and this homemade radiometer turns much slower that commercial ones.