Re: Power Lines

[Mark Sylvester <msylvest@XNET.IT>]

In Africa there are little birds (sort of sparrow-sized) with very long
tails (getting on for a metre or so). They don't fly very well, but they do
manage a sort of dipping flight. Richard Dawkins uses them to illustrate an
evolutionary point in one of his books. Anyway, a colleague of mine from
years ago told me that when she taught physics in Ghana in the 1960's they
used to call this the "two phase bird" because every now and then it
touched the other wire with its tail and got fried...

Mark

At 13:56 25/02/03 -0500, Rick Tarara wrote:
> Which shows why four legged creatures are at great risk during lightning
> storms--we at least have a chance of having our feet oriented to be on an
> equi-potential.  If caught outside in a storm with no available shelter in
> reasonable distance, the advice is to crouch down with your feet close
> together.
>
> Rick
>
> ----- Original Message -----
> From: "J Montgomery" <jmontgomery@WTHS.NET>
>
>
> > I've heard of a PBL that had a similar answer.  It was
> > based around a case in which a sudden lightning storm
> > descended on a softball game.  Two girls were standing
> > in the outfield, and the pitcher was on her mound.  A
> > bolt of lightning struck between the outfielders, just
> > a few feet away from each, yet neither was seriously
> > hurt.  The pitcher was killed even though she was much
> > further away.  The students get to read the coroner's
> > report, look at diagrams, read statements from witnesses,
> > etc.  Eventually they realize that the outfielders were
> > standing with their feet close together.  The pitcher
> > had her legs spread wide apart.  Again, it's all just
> > potential difference.
> >

Mark Sylvester
UWCAd
Duino Trieste Italy