Re: Sparks (and ions)

["Daniel L. MacIsaac" <Dan.MacIsaac@Nau.Edu>]

>    I agree with James, there seems to be no clear path that an ion can
> follow from foot to finger. The ion might diffuse through some membranes,
> but that would take a long time (although its also clear that I originally
> used electron flow far too loosely).
>
>    However, assuming  that the ions formed on your foot are trapped in that
> region, could some inductive/polarization effect through each region of the
> body due to the rearrangement of that region's ions form rather quickly and
> give your finger an opposite charge without there being a trans-body ion
> flow?
>
> Ed Schweber
I think that changes in the electric field can propagate quickly even when
charge carrying particles only move short distances.  This is the same as 
electrons in a wire moving short distances while the E field propogates
to a great distance (infinity) at near c; or air molecules moving very 
short distances individually while sound propagates much farther.  
The net effect travels the distance, individual particles do not.

Dan M

Dan MacIsaac, Assistant Professor of Physics and Astronomy, Northern AZ Univ
danmac@nau.edu  http://www.phy.nau.edu/~danmac