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

[Gary Karshner <gkarshner@stmarytx.edu>]

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?
>
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