Re: Re IONS/metals pedagogy

[mcinnes@physics.usyd.edu.au (Brian McInnes)]

Ludwig wrote
snip
> Now back to charges which are distributed on the outer surface
> of a metallic sphere. What keeps them at rest? Unless we say
> that Fnet=m*a does not apply to electrons on the sphere (a=0
> means Fnet=0) we MUST invent a force. Some say this can only
> be done by using QM. And then they say that the concept of F
> does not belong to the arsenal of its tools. Even if the concept
> of F ("Pauli F") was acceptable, the QM can not be used to explain
> things before students learn it.
>
> Something is not right somewhere. There must be an attractive
> force acting on each bunch of electrons; it must be equal and
> opposite to the repulsive force exerted on it by other bunches.
snip

Is there any chance that the electron sea is distorted in the neighbourhood
of the surface? In the accepted model there is no net force on the
electrons in the sea or on the ions in the lattice. If there are charges in
the vicinity of the metal, some polarization has occurred, that is the sea
has shifted (ever so little) so that equilibrium has been reached in the
body of the metal.  Then why not some distortion of that sea so that
eqilibrium is achieved also on the surface.  So for those surface
electrons, there is no net force: in or sideways or out.  Could this be
what is happening?

Brian McInnes

--
Dr Brian McInnes
School of Physics
University of Sydney 2006
02 9351 5982

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"What's the go of it"  the young James Clerk Maxwell.