Date: Wed, 26 Oct 2005 14:42:42 -0500


Subject: Re: radiometer


Sam: I think you need more momentum when it is evacuated. After all, since it
is heat that propels the "wrong" direction motion, half as much heat (other
side only) is not equivalent to reversing direction.

In the "momentum of electron paddle wheel" demo I used a 10 KV power supply
to "arc" into the wheel to get it rolling. Even at that potential, it was
sluggish. My apparatus was an old Leybold device with a lot of friction, I have
not seen a pumpable version of the radiometer. I would expect it to be
moderately dangerous due to the thinness of the glass envelope. Karl
Quoting sampere :

> Anybody evacuate an electrometer and shine light on it to show the
> momentum of light? Is this possible with these simple radiometers, or do
> you need more elaborate apparatus?
> Thanks,
> Sam

From Wed Oct 26 15:47:49 2005