[meteorite-list] pendulum waves

From: Sterling K. Webb <sterling_k_webb_at_meteoritecentral.com>
Date: Thu, 30 Jun 2011 01:05:04 -0500
Message-ID: <C586F5BBB52B4EE19F010FB9F9E5EA61_at_ATARIENGINE2>

The period of a pendulum depends on only
two factors: the strength of gravity and the
length of the suspending arm, string, wire,
whatever.

So you can use a pendulum to measure time
accurately but only in one place, or you can
transport a pendulum to different locations
and altitudes to measure the strength of local
gravity. Works either way: clock or gravimeter.
The first gravity measurement by pendulum
was done in 1672, and it was still the most
accurate method up until the 1930's.

If you look at the pendulums in this example,
you'll see that each pendulum is suspended
by two strings of slightly different length, each
carefully calculated to produce a period precisely
longer than the pendulum to its left by a certain
amount.

The periods are calculated so that a given time
amounts to an integer multiple of swings of each
pendulum, but a different integer multiple for
each. And just to make dam sure it works, every
ball is suspended by two strings, one connected
to the next ball right and left of it, so as to produce
a "coupled oscillator," not by a rigid connection
but only a slight influence.

"In 1665 Huygens made a curious observation
about pendulum clocks. Two clocks had been
placed on his mantelpiece, and he noted that
they had acquired an opposing motion. That is,
their pendulums were beating in unison but in
the opposite direction; 180? out of phase.
Regardless of how the two clocks were started,
he found that they would eventually return to
this state, thus making the first recorded
observation of a coupled oscillator... the two
pendulums were affecting each other through
slight motions of the supporting mantelpiece."

Of course, I was lying when I said pendulums
were the simple result of gravity and arm-length,
but it's a useful simplification. In reality, the
physics of pendulums is a complete bird's nest.

http://en.wikipedia.org/wiki/Pendulum_%28mathematics%29

http://en.wikipedia.org/wiki/Pendulum


Sterling K. Webb
----------------------------------------------------------------------
----- Original Message -----
From: "Richard Montgomery" <rickmont at earthlink.net>
To: "'Meteorite-list List'" <meteorite-list at meteoritecentral.com>
Sent: Wednesday, June 29, 2011 10:32 PM
Subject: [meteorite-list] pendulum waves


>
> Hello List....here is something for you astronomical and physical
> mathematicians to explain in "all-of-the-rest-of us" terms....anxious
> to see what you say, Richard K!
>
>
>
> http://wimp.com/pendulumwaves/
>
>
> It's a pretty grand visual!
>
> Richard Montgomery
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Received on Thu 30 Jun 2011 02:05:04 AM PDT