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From: billc@prism.UUCP
Newsgroups: sci.electronics
Subject: Lightning Rod Problem
Message-ID: <204600003@prism>
Date: Thu, 2-Jul-87 15:03:00 EDT
Article-I.D.: prism.204600003
Posted: Thu Jul  2 15:03:00 1987
Date-Received: Sat, 4-Jul-87 10:10:36 EDT
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Nf-ID: #N:prism:204600003:000:1522
Nf-From: prism.UUCP!billc    Jul  2 15:03:00 1987


All this talk about ground resistivity and lightning reminds me of a 
question I came across in freshman physics.  Wait! Don't skip to the
next note yet!

To put it in historical perpective, when Benjamin Franklin invented the
lightning rod, he advocated that the rods should be pointy on the end
in order to provide the greatest protection.  On the other side of the
Atlantic, however, the British got the idea that lightning rods with
a ball the end were better, and in fact a law weas passed that all
lightning rods in England should have balled ends.

Of course, the freshman physics problem was to compute the electrical
properties of both rods, which we dutifully did.

Now the clincher: No one has any arguments about the different properties 
the two types of rods have, since no one argues about the physics.  But
the story I heard from my professor (whom I very much respect as a physicist
and teacher) is that opinions were changing as to which rod was really more
effective at protecting a house in an electrical storm.  The traditional
answer is that pointy rods are better, but some people re-examining the
problem are (were) beginning to think that perhaps the 18th century
House of Commons may have actually had a point (though probably for the
wrong reasons, since they didn't know much about modern EE.)

I would appreciate respones on this, or posted replies if you have something
on this of general interest.

Bill C.		billc@mirror.TMC.COM
		{mit-eddie, ihnp4, wjh12, cca, cbosgd, seismo}!mirror!billc