Date: Wed, 30 Oct 2002 10:03:37 -0500

Author: Bill McNairy

Subject: Portable Vacuum Pumps


Hello all!

Thanks for all of the assistance with why candles have their lovely blue
and yellow lights-- however the discussion still rages here.

On another note, I've just built the 'tennis ball vacuum cannon' as
shown on Dick Berg's website at Maryland. It seems that a good seal is
only possible for me by using a mechanical vacuum pump rather than the
hand operated version we use with the Magdeberg spheres. In the hopes
of taking this cannon on outreach visits to schools I would like to find
a reliable yet portable vacuum pump. Fisher has one (part S41328F) for
$635. Is this the best value on the market, or is there a less
expensive alternative that offers similar pumping speeds and low pressure?

Thanks for all of your assistance!


From NC where we almost all of us are awaiting basketball season (except
NCSU fans.)

William W. McNairy, Ph. D.
Room 104I (919)-660-2689
Dept. of Physics, Duke University
Box 90305 Durham, NC 27708