Re: radiometer paradox

[Pete Lohstreter <petel@tenet.edu>]

At 01:46 AM 6/14/97 -0500, you wrote:
> On Sat, 14 Jun 1997, Bob Sciamanda wrote:
> > Addendum:  If you refrigerate the Crookes radiometer sufficiently, the
> > thermal effect can be reduced so that the radiation pressure efect
> > dominates and the thing turns "backwards" (ie., in accordance with 
> > Joseph's expectations) under a strong light.
>
> At what temperature is this effect seen?  How do you illuminate it?

I have done this by using a standard 'heat' lamp for the initial
illumination.  When the radiometer is in full motion, turn off the IR lamp
and slowly pour cool water over the globe.  The vanes will slow to a stop
then start to rotate the other direction.  The Black vane radiates the
stored heat faster than the white one and is for a short time cooler that
the white vane.  The previous explanation then applies

Pete