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Re: First EM lab



At 09:19 PM 1/13/02, Herb responded to Joe's teaser in this way:

> > I hate to belabor it, but ......xx ..............#@$*&%??&%??
> > What technique do you find most useful for measuring the
> > charge on a piece of scotch charged tape?
> >
> Just think about it for a while. That's what this problem is all
> about. ;-)

Here are a dozen of my thoughts... after thinking for a long long
while...

1. Use a charged calibrated electroscope ?
2. Use a calibrated electrometer ?
3. Set up apparatus that measures microforces between the scotch tape
and a charged object of the same size that has a known charge ?
4. Offer to give a knowledgeable professor a barometer if he tells me
how to measure the charge on a piece of scotch charged tape. ?
5. Give the problem to students in one of my physics classes
for homework or as a question on their final examination. ?
6. Contact Joe Haefner's wife and find out whether or not Joe
knows the answer himself?
7. Spend $70 for a book that Joe Haefner recommends that might
or might not have the answer?
8. Contact the manufacturers of scotch tape and ask their customer
service girl ?.
9. Ask one of my friends who gives oral exams to physics doctoral
candidates to include this question on all of his future interviews?
10. Apply to the NSF for a grant to research the answer to my question?
11. Pose my question to members of this Phys-L listserve and
hope for a correct response within the next year or two?
12.Do a thorough computer web search using the GOOGLE or several other
search engines and hire someone to translate hits in several of the
foreign language publications?.


Seems like this old cynic from NooYork and this old cynic from Altus are
going to have to go along with the hints so far.
That an electric force is capable of lifting off a confetto at a particular
distance.
We are to choose an inverse square law (assuming the point of a plastic
pen) rather than an inverse law for an expanse of Scotch tape.
And we have been given some suggestion about the likely charge density on
the complex starch of which we speak. I suppose we need to measure the mass
of the confetto - can it be more than 0.1 mg? My balances will not
directly measure
so small an item. Perhaps measure a toilet roll? That's just too indirect....

How do we proceed next, maestro?





Brian Whatcott
Altus OK Eureka!