20110806 Crookes radiometer - Could it be photovoltaic electrostatic (c) J Hartikka.AVI

Electrostatic Explanation of Crookes radiometer, the 'light mill'. The usual explanations are based on radiation pressure and heat engine. However, I wonder if it could be photovoltaic..?

The blades or vanes of this example appear be of some natural mica or similar panted black on the other side. The movement is directed towards the bright (or silver or white) side of the blades. We know that in very low pressure light charges some metals and micas electrically - the 'photovoltaic' effect used in photocells.

Now think about light releasing electrons from the bright side of the blades. This will cause similar voltage between the bright side of the mica blades and the inner surface of the almost vacuum glass bulb as between photocell electrodes.

Because glass is good insulator, as well as the mica blades of this radiometer, this photovoltaic potential will behave as surface voltage, making it very eager to attract the opposite potential by common electrostatic or 'Coulomb' force.

So by my guess there might be an electrostatic pull between the bright sides of the blades and the glass bulb inner surface, attracting the rotor to start move..?

Conventional explanations: http://en.wikipedia.org/wiki/Crookes_radiometer

Category:

Science & Technology

Tags:

• Crookes
• radiometer
• electrostatic
• force
• explanation