From: Gene Gordon (ggordon1@rochester.rr.com)
Date: Thu Apr 07 2005 - 15:54:17 PDT
Message-ID: <023701c53bc4$ba98ebe0$6602a8c0@Fred> From: "Gene Gordon" <ggordon1@rochester.rr.com> Subject: VanDeGraaff question Date: Thu, 7 Apr 2005 18:54:17 -0400
Hello all!
A physics colleague of mine asked me a question today which neither he, I,
nor any of the other physics teachers in our school (we have six) could
figure out the answer for. While he was doing a demo yesterday with his
class, he did something that all of us usually do, but his students asked
him a question that he at first answered and then decided his answer was
wrong. The demo and question go like this...
We set up a person on the VanDeGraaff generator and do the usual stuff(hair
raising, sparks from fingertips, flying popcorn, etc.) At the end we have
students line up and slowly, one by one, link hands with the student
touching the VDG so as too create a long ring of students. The teacher
grabs onto the last student and then suddenly grabs onto the water faucet
and of course everybody is shocked and lots of giggling ensues. The student
touching the VDG then asked the teacher why his shock was barely anything
while others (the ones near the teacher) were complaining about how bad the
shock was. At first, the teacher quickly answered that maybe it was because
they were at the end of the line and therefore "all the charge" in the line
traveled through them, while those at the beginning did not have much to
leave them. However then he thought( as well as all the rest of us) that
this would break Kirchoff's laws and that all of them had to have the same
current.
After a day of searching and discussing this, we are stymied. Can anyone
help explain this?
BTW, At first I thought that this might just be a perception problem but
after multiple experiments, we have decided it is not.
Thanks,
Gene Gordon
Fairport High School
Fairport, New York
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