PSN-L Email List Message

Subject: John Lahr's diamagnetic levitated graphite video
From: "meredith lamb" mlamb1@..........
Date: Fri, 13 Apr 2001 18:15:44 -0700

Hi all,

On John Lahr's web site is acouple pictures of his spectroscopic
graphite rod levitating over a unique magnet setup.  Especially good is
a video of the graphite rod freely oscillating back and forth over
the magnets and within its channel.  Its a 1.2mb MPEG download,
which will play on the Microsoft Windows Media Player, and with
that programs controls,  it can be replayed of course.  Its unknown
whether it will play the video with other browsers?  See:

This particular basic type layout was found by David Lamb around
January 2001; and it seems to have a real good potential for use as
a tiltmeter/seismometer with development of a light sensor
circuit, and the application of a aluminum damping medium with
a "flag" to discern motion.

Currently the magnets are not available per Forcefield, but its
hoped that a quanity become available ~ June/July 2001.  The
spectroscopic rods used are likely old stock (circa 1960's-1970's),
but its highly likely that there are sources of similar diamagnetic
(or better or worse) 1/8" spectroscopic rods available.  One
real advantage with this graphite is that its cost is greatly lower
than with some other special graphite used in levitation.

There are plus's and minus's possible with this type of layout.
Probably most evident is that the levitation assembly is itself
most of the usual "boom, mast, mass and etc", involved in 
construction. When leveled and the rod length adjusted, its
possible to get periods of from ~ 1 sec up to ~ 4 seconds.  
One negative is that with the "mass" being lightweight, it will
very likely have a unknown amount of Brownian noise associated 
with it.

Regards, Meredith Lamb


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Larry Cochrane <cochrane@..............>