How does the button on the pedestrian crossing lights work? Does it actually send some sort of signal to the traffic lights, or is it just a psychological thing? It seems rather random timing-wise.
posted by divabat on May 14, 2008 - 21 answers

How to make a simple railgun to demonstrate the principle to children? [more inside]
posted by jjsonp on Jan 19, 2007 - 12 answers

I'm looking for a book that teaches electricity well. The Mims book definitely doesn't cut it - I want something more along the lines of "The Way Things Work" in clarity and accessibility, but I still want it to actually teach the underlying math; i.e., I want it to show me the material in pictures and equations. [more inside]
posted by dmd on Feb 11, 2006 - 10 answers

What are some good resources to learn about basic electricity? [more inside]
posted by frenetic on Aug 11, 2005 - 13 answers