From: SFPhysics <SFPhysics@aol.com>
Date: Sat, 25 Apr 1998 13:14:26 EDT
To: pinhole@exploratorium.edu
Subject: Re: Pinhole Daily Digest
> The TI schedule for Saturday May 2 calls for electrostatics.
> So what questions or suggested experiments do you pinholers have on
> electrostatics?
> Paul D
Sefl's Law of Demonstrations States that it has to either Light Up, Move, or
Make Noise to get the student's attention. Time honored experiments such as
Volta's Hail Storm, the Corona Discharge Spinner, the Disappearing Smoke Tube,
the Electric Racing Ball, the Electrostatic Bells, Saint Elmo's Fire Stick,
the Lightning Plate, the Neon Magic Wand etc., etc. are all good student
motivators of interest in electrostatics. Many of these may be made for just
pennies. i.e. The Corona Discharge Spinner need be nothing but a cork with a
sharpened nail inserted axially up through it to allow a thin copper or brass
sheet spinner cut in something of an "S" shape to sit on the point of the nail
and held in place by an indentation in the metal placed so as to balance the
arms of the "S". (English teachers please do not run to your screens with a
red pencil to label the above sentence "run-on"!)
BTW- my Van DeGraaf generator output has fallen off by about 25% since the
cold dry winter air has gone. The simple hand-turned electrostatic generator
from Cenco won't even give enough of a charge to light a small Ne-2 (75V
typical) lamp. Have fun and good luck on your workshop.
Best wishes to all Pinholers -
Al Sefl
SFPhysics@aol.com
p.s. Science First has a nice catalogue of electrostatic and other physics
demonstration materials. The e-mail is info@sciencefirst.com and FAX 716
874-9853. These people have a small Van DeGraaf for only $109.95 and it is
good for 200KV (mine has reached 300KV). The same machine may be bought as a
kit for less, $89.95 if memory serves. The same generator at the big
suppliers run for $139.95 and up. Science First manufactures much of their
own equipment and buying direct from them saves precious edu-dollars!