The Crookes Radiometer 
The radiometer is made of a glass bulb from which most of the air is removed, therefore it creates a partial vacuum and a rotor that is mounted on a vertical support inside the glass bulb.
 It was invented in 1873 by a chemist named Sir William Crookes, the radiometer idea came to him when he was weighing samples in a evacuated chamber to reduce the effect of air currents, after some time he noticed the weighs were moved by the sunlight shown on the balance.  


YouTube Video

Rolando Martinez,
Mar 25, 2014, 5:13 PM