Date: Sat, 06 Jul 2002 09:32:40 -0400 (EDT)


Subject: Coulomb


We tried to find Christmas bulbs in January and couldn't. We also
unsucessfully tried coating ping-pong balls. Rich Fiorillo had the
brilliant idea of using small (two-inch) copper toilet tank floats.
They're available at any plumbing supply and cost about $6 each.
They're sturdy enough they can withstand a lot of student misuse. They
even have a threaded hole for the insulating support.

Joe Pifer

> But this takes us far from physics indeed. Back to the purpose of the
> list: Does anyone have a good source of lightweight conductive balls?
> I'm thinking of graphite-coated ping-pong balls or equivalent.
> Christmas ornaments don't seem to work well, as the ones available
> here have their metallic coating on the inside of the blown glass.
> This makes charging, and transferring charge, quite difficult.
> (Nevermind the difficulty inherent in BUYING Christmas ornaments on
> July 5th in a small town. I have contributed greatly to my reputation
> for eccentricity today!)
> Is there some good, and easily available, conductive paint for this
> purpose? Ann Hanks, if you're still on the list, what does PASCO use
> to paint the ping-pong balls in their Coulomb balance?
> Eric
> --
> --------------------------------------------------------------------
> Dr. Eric Ayars
> Assistant Professor of Physics
> Walla Walla College
> (509) 527-2476