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Re: [Phys-L] --EXTERNAL-- Graphite resistivity



Hi Paul-

That was the Line of Resistance workshop presentation that I gave (along with 2 others) at that AAPT meeting.

It was further developed in conjunction with the Institute for Chemical Education at the U. of Wisconsin, and the kit is still sold:
http://ice.chem.wisc.edu/Catalog/SciKits.html#Anchor-Line-52

Some extensions and other presentations that were developed after that are at:

http://www.sci-ed-ga.org/Websites/gasef/images/pdf/Line_of_Resistance_Addenda.pdf

http://www.sci-ed-ga.org/websites/gasef/images/pdf/APS%202005%20March%20Teachers%20Day%20Line%20of%20Resistance.ppt

Graphite pencils from an art store such as Aaron Brothers work well as to do many other soft pencils. The best bet is just to buy a bunch of different pencils and test them out. Graphite pencils are often better than regular pencils because the regular pencils use other non-conductive fillers (clay) in them.

Larry Woolf


-----Original Message-----
From: Phys-l [mailto:phys-l-bounces@www.phys-l.org] On Behalf Of Lulai, Paul
Sent: Friday, March 04, 2016 1:23 PM
To: Phys-L@phys-l.org
Subject: --EXTERNAL--[Phys-L] Graphite resistivity

Hello.
I am getting ready to do a resistivity lab that I've done for a decade but I ran into a problem. The art pencils that I've been using are gone. They apparently vaporized along with my packet of materials from an old aapt workshop a decade or more ago.
I remember that art pencils were better because...
I don't remember...
I am tempted to pick up softer leaded pencils so the lead would get into the cracks of the paper.
Does anyone have a quick recommendation?
Thanks for your help.
Paul.
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