There was something I didn’t see addressed which I feel definately needs attention. The explanation on electron polarity is great but missing something. Metals are generally conductors which means that electrons flow freely throughout the material depending on outside electomagnetic pulls. We all know that aluminum conducts electricity as we use it daily on computers. In this way you create a large, overall polarity in the object…but not in aluminum…why?
Ciao
Vince
Please add a link to the column you are discussing.
This is probably it:
http://www.straightdope.com/classics/a3_339.html
Yes, that was it…sorry.
I’m not sure I understand the question. The fact that electrons move easily through metals tends to {i]destroy* rather than create a polarity.
When electricity is flowing through aluminum, there is an associated magnetic field. Many years ago I took my VW speedometer apart. It was a “bicycle-bell” shaped aluminum housing, to which was mounted the needle, and a spring that pushed the needle towards zero. Just inside the aluminum bell was a magnet mounted to a flexible shaft connected to some axle. When the wheels turned, the shaft and magnet spun, inducing “eddy currents” in the aluminum bell, creating a magnetic field, which interacted with the magnet so the aluminum housing tried to follow the magnet. The position of the aluminum bell (and, therefore, the needle) depended on the return spring force and the speed at which the magnet spun. I suppose some other speedometers work the same way.
jrf