Re: First EM lab

[Joe Heafner <heafnerj@VNET.NET>]

> From: Tina Fanetti <FanettT@QUEST.WITCC.CC.IA.US>
>
> We do have the stuff to map electric field lines...the lab write-up I have includes both magnetic and electric field lines...although I could rewrite it.
I don't even do this one any more. It's rather useless. There is so much more to be learned by playing with scotch tape. In Matter & Interactions, such experiments lead to an understanding of polarization, fixed and induced dipoles, neutralization of charge, and estimating the number of excess charge carriers on a piece of scotch tape. The McDermott tutorials make an excellent, and more modern, replacement for the old fashioned traditional "labs" and are vastly more instructive.

Another extremely useful lab is the following:

Take a plastic ball point pen and rub it in your hair so that it acquires a net charge. Hold it a couple of centimeters above a small piece of paper (e.g. a tiny bit of paper from a notebook sheet). Find the height at which the paper is just lifted by the electric force. From this, estimate the polarizibility of carbon.

Have fun!

> The other option is to start with circuit stuff.
The M&I approach downplays the traditional circuit stuff in favor of a microscopic description of circuit bahavior. Besided introducing some very basic concepts from solid state physics (i.e. the Drude model), students find out what REALLY makes circuits work. This is mentioned in the vast majority of traditional texts that are currently used.




Cheers,
Joe

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