From: "JACK L. URETSKY (C) 1996; HEP DIV., ARGONNE NATIONAL LAB, ARGONNE, IL 60439" <JLU@hep.anl.gov>
Date: Wed, 19 Feb 1997 14:39:55 -0600 (CST)
Hi all-
Dewey asks:
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Exactly how is this established, i.e. the existence of two kinds of charge?
I'd be interested especially in how this is accomplished.
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I do this in my dialogue labs. I think it's lab 3 (E&M). After
establishing charge and attraction from electric induction, we learn that
two charged object repel. Next we must establish two objects, each of which
is definitely charged, and find that they attract. Conclusion: charge must
come in (at least) two varieties.
You can do all this with scotch tape and/or pith balls. It's all
in Arons' book.
Regards,
Jack