Oh, a warning about playing with glass & charge....
If you do decide to play with charges stored on glass plates wear eye protection because every once in a while the mechanical stress is more than the glass can take and it will shatter. One way you can do this is to go to your local video arcade and purchase one of the glass sheets they use to cover their pinball machines. Then carry that glass plate by the edge in your hand as you scuff your feet across a nylon pile carpet (again wear safety glasses). The result about 1 out of 100 times, or if you've got lots of patience and can afford hours to scuff feet on carpet, is that the glass plate will shatter with a report about equivalent to a .22. Anyone watching should also wear eye protection as the shards can go 20ft. or moe. It's best if you do this on a cold dry day. ____________________________________________________________________ Lawyers ask the wrong questions when they don't want the right answers. Scully (X-Files) The Armadillo Group ,::////;::-. James Choate Austin, Tx /:'///// ``::>/|/ ravage@ssz.com www.ssz.com .', |||| `/( e\ 512-451-7087 -====~~mm-'`-```-mm --'- --------------------------------------------------------------------
At 1:38 PM -0800 11/21/98, Jim Choate wrote:
If you do decide to play with charges stored on glass plates wear eye protection because every once in a while the mechanical stress is more than the glass can take and it will shatter.
And when you do your "...and then take away one of the copper plates" experiment, you'll find that force is needed. Force times distance is energy. The energy to pull one of the plates away equals the 0.5CV^2 energy no longer stored in the capacitor. The energy stored is not stored either on the plate or on the insulator. It is in the electric field. A free-standing single conductor can of course store a charge. And can of course have an electric field. Frankly, Jim, you no doubt have a lot of practical experience building Tesla coils, Van de Graf generators, whatever. But you also have what can only be described as "crankish" notions about how electromagnetism works (pace last week's discussion of charges inside conductors, a la Gauss), about prime numbers, and so on. --Tim May "I swear to tell the truth, the whole truth, just the way the President did." ---------:---------:---------:---------:---------:---------:---------:---- Timothy C. May | Crypto Anarchy: encryption, digital money, ComSec 3DES: 831-728-0152 | anonymous networks, digital pseudonyms, zero W.A.S.T.E.: Corralitos, CA | knowledge, reputations, information markets, Licensed Ontologist | black markets, collapse of governments.
participants (2)
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Jim Choate
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Tim May