Re: Scotch tape, "Sticky Electrostatics"

[brian whatcott <inet@intellisys.net>]

At 21:52 2/21/98 -0800, Bill Beaty wrote:
....
>   http://www.eskimo.com/~billb/emotor/statelec.html
>
> I created the original demo in order to fight the widespread misconception
> that "static electricity" is caused by friction.  (As opposed to being
> caused by contact, as in "contact electrification").  I was doing K-6
> textbook consulting at the time, and found that the authors had great
> difficulty accepting that "static electricity" could be caused by simple
> contact.  All the books (and most encyclopedias) state that "frictional
> electricity" is from friction....

> William J. Beaty 

I checked the fourteenth edition of the Encyclopedia Britannica, 
looking for the "frictional electricity" explanations.
 And sure enough, just two pages before the interesting article headed
"Elementary Education" I see that the short piece on the Electrophorus
(which is the moveable plate capacitor arrangement created by Volta in
1775) refers one to the extended article on Electricity in the same volume.

Although this seems to make it clear that placing the top plate of the
Electrophorus in contact with the dielectric/plate sandwich and discharging
the top plate simply by touch is the means of continually providing a given
charge to that plate, I recall that the method of initially charging the
dielectric, traditionally pitch or resin, but which may be substituted with
glass, is given as frictional rubbing.

Come to think of it, what was perhaps the prototype of all electric
generators - a ball of sulphur turned with a handle was charged by
stroking the rotating surface with the hands.
 This was undoubtedly described as frictional charging.

Whatcott