Re: Crooke's Radiometer

["J. Andrew Tompkins" <jatalbq@mindspring.com>]

As I recall the speed of rotation of the vane assembly is somewhat
proportional to the infrared energy deposited on the vanes, and thus could
give a measure of the radiant energy deposited.

Andy Tompkins
Woodstock, GA

jatalbq@mindspring.com


>On Tue, 6 Apr 1999, Otto G. Raabe wrote:
>
>> April 6, 1999
>> Davis, CA
>> 
>> Maybe it is called a radiometer because (1) it responds to electromagnetic
>> radiation in the form of light and especially infrared radiation, and (2)
>> it was named before the discovery of ionizing radiation.
>
>	-I would bet that it was meant as a demonstration of radiation
>pressure, the fact that radiation has momentum, and sometime later
>somebody noticed that the rotation was in the wrong direction for that
>explanation.
>
>> 
>Bernard L. Cohen
>Physics Dept.
>University of Pittsburgh
>Pittsburgh, PA 15260
>Tel: (412)624-9245
>Fax: (412)624-9163
>e-mail: blc+@pitt.edu
>
>
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