twice what you show. As well as I remember, it was much more
over dampening via aluminum foil extending over dual end
magnets, simply because the increased PG size could sustain
the load. Real adjustable dampening remains elusive. &nbs=
p;
The web page itself doesn't show the specific aluminum foil
thereon, but it is actually; K&S precision metals, 36 gauge
(.005" thick) foil. This is general hobby shop sold material. &n=
bsp;It's
sold in either rolls or in a set of 3 sheets. I've no refer=
ence to
it's purity, but it certainly worked very effectively for that mo=
del,
and much better than everyday scrap aluminum or household
aluminum foil with it's suspect magnetic impurities. It's v=
ery
easy to cut, shape or flatten.
The two "end magnets" size is 3/4 X 1/2 X 1/4" and are
magnetized through the 1/4" thickness. I'm not now sure of
their rating, but it was likely between N40 and N45. Although
it's contacts were magnetically conflicting, they actually
mechanically held very well.
The iron used remains ~ nondescript, it was just iron/steel
that was flat and thick enough to secure the magnets down
very well.
One of the most interesting aspects of this model is that by
simply separating the PG by varying distances, the natural
period changed from a low of ~ 4s up to ~ 7 seconds easily.
Longer periods were "hinted" to be attainable, but the
mechanism for doing so remains elusive. However, this
was only using the one model; it maybe specific to variations
in the individual setup and it's underlying magnets fields
variations. This has been noted by other individuals in
their setup models.
I used 1/2" thick (height) magnets. The difference between
1/4" thick and 1/2" thick magnets seems to be one of more
enhanced vertical fields acting on the PG with thicker magnets.
Actually, the most maddening aspect of anyone initially creating any&n=
bsp;
diamagnetic model is always that of just getting, and making the<=
/DIV>
dimensions of the PG size it needs. I did make a excess of =
that
specific web pages PG size, for anyone who has a interest in
pursuing such...within numerical limits of course They are<=
/DIV>
reasonable well made table sawed units.
One of the main attraction draws I have for diamagnetic levitation&nbs=
p;
experimentation is that the; "usual pendulum/s" numerous
mechanical physical parts are not required.
Meredith
On Sun, Jul 8, 2012 at 7:40 AM, Randal=
l Peters
<PETERS_RD@=
mercer.edu> wrote:
For those of you who have had an interes=
t in levitating graphite, you may find interesting a prototype instrument t=
hat I recently built. I first witnessed the intriguing possibilities =
of diamagnetic levitation through a demonstration by Chris Chapman about ha=
lf a decade ago, when I visited with him in England. Only recently di=
d I come to know about pyrolytic graphite (PG) plates, as opposed to the ea=
rlier experiments with rods. Because the plates are amenable to use w=
ith my fully differential capacitive sensors, I decided to try my (typicall=
y frustrating) hand at building such a tiltmeter/seismometer=E2=80=94that I=
have called in the following online paper an =E2=80=98earth motion=E2=80=
=99 detector.
http://physics.mercer.edu/hpage/diamagne=
tic/diamag.html
The outstanding performance=
of this prototype really surprised me. My thanks to Meredith Lamb an=
d John Lahr (deceased, whom I admired greatly) for their pioneering work th=
at steered me this direction,
Randall=
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