Re: Sparks

["Bob Sciamanda" <trebor@velocity.net>]

Another way of describing the changing situation as the charged finger
approaches the doorknob is in terms of the increasing potential gradient
(ie.; the E field) in the intervening space  - until air ionization (a
spark) occurs.  (What was a charged capacitor is now very leaky!)

Bob Sciamanda

-----Original Message-----
From: Bob Sciamanda <trebor@velocity.net>
To: phys-l@atlantis.uwf.edu <phys-l@atlantis.uwf.edu>
Date: Friday, September 04, 1998 10:12 PM
Subject: Re: Sparks


> Hi Ed,
> Yes, I agree with your intuition . . . The proximity of a conductor
> (doorknob) changes the field configuration.
> Before, the finger electrons may have been repelling each other somewhat
> "equally" in all directions; now the forces are somewhat more
> concentrated toward the induced positive charges on the doorknob
surface.
> (Consider how the field of an isolated charge changes as it is
approached
> by a conductor . . . the size and shape [and is it grounded?] of the
> conductor are pertinent factors affecting the details of effect.)
>
> Hope it's helpful.
>
> Bob Sciamanda
> Physics, Edinboro Univ of PA (ret)
> trebor@velocity.net
> http://www.velocity.net/~trebor
>
> -----Original Message-----
> From: Ed Schweber <edschweb@ix.netcom.com>
> To: phys-l@atlantis.uwf.edu <phys-l@atlantis.uwf.edu>
> Date: Friday, September 04, 1998 5:19 PM
> Subject: Sparks
>
> > ...
> > . . . My intuitive response (which is just that, a plausible
> > guess) was that the electrons on your finger also induce a positive
> charge
> > on the doorknob and the force from this induced charge adds to the
force
> > from the electron repulsions. Is it that simple
> > . . .
> > Ed Schweber