From: "Sidney Keith" <sidkeith@hotmail.com>
To: pinhole@exploratorium.edu
Subject: Square Laws
Date: Tue, 25 May 1999 08:23:38 PDT
Sara raises a subject I'm passionate about, because it prevented me from
becoming a scientist! I used to bug my physics teacher in high school all
the time about why the equations we were studying, especially the variance
of gravity over distance, were based on squares. He would always answer
that the experiments just showed that; he saw no meaning in asking why.
Eventually I concluded that science was anti-intellectual, stubbornly
refusing to budge an inch beyond the phenomena to pose interesting
questions. Much, much later I came across the explanation that's embodied
in one of the snacks, that force weakens with distance by having to fill the
area of a sphere as it expands. The geometry -- the area of the surface of
a sphere -- gives the square law. That's surely not the whole story, but it
excited me enough to make me study science, especially physics, nonstop for
years afterwards! I think it's important to draw the link between physics
and geometry whenever possible; it connects two subjects students know well.
I still wonder about the square laws, though. My current musing is that it
has something to with the continuity of gravity's action -- even while the
object is responding to gravity's past pull, it is still pulling and so
piling pull on pull -- that seems to give a mathematical square function.
I'd love to see anyone else's intuitions on the subject.
On a deeper level, I understand that gravity and electromagnetism obey
square laws because their transfer particles are bosons (the graviton and
the photon). Where the particles are not bosons (e.g. the gluons of the
strong force), the square law does not apply.
_______________________________________________________________
Get Free Email and Do More On The Web. Visit http://www.msn.com