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Re: IONS on metals/dielectrics



Dear Sam,

The following is a quote from one of your current postings.
-----------------------------------------------------
"In a static situation, the current is zero. If there is a current
inside a conductor, the electric field inside the conductor must be
non-zero. When I turn off the Van de Graaff, the current into or out of
the dome (neglecting leakage on humid days) is zero. If there were
charges through the thickness of the metal, or distributed on the inner
surface of the dome, then an electric field would exist inside the metal
of the dome. If this is true, then there must be an electric current.
If this were true, you would have a perpetual motion device! You would
detect magnetic fields around your dome. The dome would get hot. And
this could continue forever. This of course cannot happen. You agreed
that the charge was static."
---end of quote-------------------------------

I am becoming miserable over my stupidity in this matter. I feel like I
once did when a magician pulled a quarter from my ear. I knew that it
had not come from my ear, but I had carefully inspected his hands and it
wasn't there either.

---A portion of the above-------------------
"In a static situation, the current is zero. If there is a current
inside a conductor, the electric field inside the conductor must be
non-zero. When I turn off the Van de Graaff, the current into or out of
the dome (neglecting leakage on humid days) is zero."

---Yes, of course---

---Another portion-----------------------------
"If there were charges through the thickness of the metal, or
distributed on the inner surface of the dome, then an electric field
would exist inside the metal of the dome."

----Well, I feel trapped in a semantic snake pit.

----In my experience, (not text book) the only way to gain or lose
----charge is to move electrons around. Induced charges are
----accomplished by using the force available in an external field of an
----existing charge to move electrons in a prescribed way in another
----object. In any case, we are still moving electrons around.

----I am going to interpret your word "charge" above to mean either free
----(excess) electrons or "lack there of" in a metal structure. If
----this structure were a flat plate I may be able to convince myself
----that any excess electrons would mass on the surface. The whole
----surface.

----My very flexible reasoning would proceed like this: If a balloon
----full of electrons were to burst inside of a conducting medium
----(e.g. copper), the electrons would be repelled from each other and
----would get as far away as they could (e.g. the surface). and
----would distribute themselves equally, commensurate with the
----repulsive forces which are somewhat dependent on the geometry
----(e.g., corners and edges)

----Now, if this plate were to miraculously be pressed into a half
----sphere (salad bowl) without adding to or removing charge, it
----is interesting to contemplate the realignment of surface
----electrons. By adding spherical sections to the skirt of
----the bowl it more closely approximates a sphere, and the
----electrons, trying to get as far away from each other will
----appear to migrate to the outside surface.

----If the inside surface is not in communications with the outside
----surface, then indeed, the inside surface could be considered to
----at a low state of charge. But this, I worry over.

----I agree that no "field" exists inside of the sphere because all
----surfaces are at the same "potential" (which is a word that I
----consider pivotal) therefore there can be no field between any
----two points of the same potential.

----I believe that if a grounded conductor is carefully slipped
----through a hole in the side of our sphere and brought close
----to any surface, that there would be a mass exiting of electrons
----as they bridged the gap on their way home. The surface electrons
----would take the path of least resistance and many would flow
----right through the metal that the sphere was constructed of.

----If that will happen, then a "potential" must exist on the inside
----of the sphere even if a "field" does not. If a potential exists,
----then the insertion of a new charge (on a tiny, tiny metal ball)
----inside of our sphere must instantly create a field between the
----inside surface of the sphere and the surface on our tiny ball.
----Of course if the ball has the same potential as does the
----potential of the inside of our sphere, no field would be created.
----But that is a special case and I am not near as interested in
----special cases at the moment.

----I believe that you now see my dilemma. Electrons moving into the
----sphere would be of X potential and the sphere of another. The
----instant of entry would produce fields commensurate with their
----different values. And the question is exactly what is taking
----place.

----This line of reasoning (up until this moment it had only been
----a feeling of dis-eze) leads me to think that there is little
----difference in what the electrons find at the top of the belt
----in either the external or the internal VGM.

I regret dragging anyone through this hodgepodge of poor thinking but
God made me this way, and I can't help being a little slow at times.

Somewhere in all of this there is a flaw and I will be grateful to have
it straightened out. Thanks again for your patience.

Bill