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Re: [Phys-l] two kinds of electrical charge ????????



Bu it's all in the point of view. There is nothing wrong about considering the positron to be a hole in the sea of negative electrons. or as (Feynnman-like) an electron traveling backward in time.
Regards,
Jack



On Mon, 30 Jul 2007, Gary Karshner wrote:

John,
Your argument sufferer from a problem similar to the old
philogiston theory of heat. Under this theory you started with an earthy
like substance (a calc) and added fire ("philogiston") and get a metal. In
terms of Lavoisier's chemistry you are taking an oxide adding heat and
getting a metal. This system work well for chemistry for about eighty years
until chemists started doing careful weighing of their chemicals before and
after the reaction. It was even supposed by some that philogiston had
negative weight.
Physicist tend to think of electric charge in terms of conduction
in metals. But chemists quickly realize that electrolytes have charges
(ions) moving in two different directions, as do solid state physicists. Of
course both of these can be thought of as an excess or deficiency of
electric fluid. Solidstater's even give holes mass. The system ultimately
breaks down in particle physics where bodies with different charges have a
reality. The mass of a positron is real not negative, and as far as we can
tell identical to the electron. Something that wouldn't necessarily happen
in a single fluid world.
Although many old theories work, that is why they existed in the
first place I don't think we should humbug our students with models that
will ultimately fail unless like Newton's we can model much of what we see
using them. I point out to my astronomy students that Aristotle argues that
the earth can't rotate since if it did there would be great winds when you
went outside. But I do this to create a straw man to make them ponder
inertia, not because the theory seems work in a special case.
I apologize for getting on a soapbox.
Gary

At 02:33 PM 7/30/2007 -0400, you wrote:
Hi --

Recently I was asked about the following statement:
«There are two kinds of charge, namely positive charge and negative
charge.»

That expresses the /two-fluid/ model of electrical charge.

1) Would anybody care to comment on this, perhaps contrasting it with the
one-fluid model?

This seems fundamental to any physics course ... yet there seems to be
more divergence of opinion than I would have expected.


2) As you might have guessed, I have an opinion:
http://www.av8n.com/physics/one-kind-of-charge.htm
Suggestions or comments on my analysis are welcome.

I suspect there are arguments and counterarguments I have missed, although
most discussions I've seen fall into the category of PbBA (Proof by Bold
Assertion) which I don't find helpful.


3) I'd be interested to hear briefly: What text are you using, and how
does it handle this issue?

_______________________________________________
Forum for Physics Educators
Phys-l@carnot.physics.buffalo.edu
https://carnot.physics.buffalo.edu/mailman/listinfo/phys-l

_______________________________________________
Forum for Physics Educators
Phys-l@carnot.physics.buffalo.edu
https://carnot.physics.buffalo.edu/mailman/listinfo/phys-l


--
"Trust me. I have a lot of experience at this."
General Custer's unremembered message to his men,
just before leading them into the Little Big Horn Valley