PSN-L Email List Message
Subject: Re: Pendulum in a fluid?
From: "Geoff" gmvoeth@...........
Date: Wed, 27 Aug 2008 17:39:47 -0700
I have done this and it simply acts to damp and not change the period.
It works best if you get your hands on silicone ? oil.
The stuff used in womens implanted falsies ?
but it is expensive and you can not buy small quantities.
The reason silicone oil is best because the visconsity is most
constant with temp changes. The next best is motor oil
that is synthetic maybe straight 50 weight oil.
never use simple common motor oil unless you can
keep the temperature constant.
Immerse the entire weight in oil but the mass must
have a projected image in the horizontal plane
identical in all directions ( e.g. cylinder or sphere )
protect the oil from contamination.
I have found such a pendulum that has a magnet and solinoid
arrangement to give good pictures but you will not know
if the signal is n/s or e/w because such a thing as described
by Forrest Mims III in the 1970s is sensitive in the entire
----- Original Message -----
From: "Paul Cianciolo"
Sent: Monday, August 18, 2008 1:22 PM
Subject: RE: Pendulum in a fluid?
>I think this would lower the "Q" to a very low value, but not increase the
> period significantly.
> One newbies opinion
> -----Original Message-----
> From: psn-l-request@.............. [mailto:psn-l-request@.................
> Behalf Of tchannel1@............
> Sent: Monday, August 18, 2008 1:44 PM
> To: psn
> Subject: Pendulum in a fluid?
> Hi All, Just a thought...Has anyone explored a simple 36"? pendulum, say
> having a 2? second period, then containing the pendulum in a fluid. The
> pendulum still should move from side to side, but with a longer period? I
> have no idea, how to do this, or what the result would be.
> I think the result would be similar to an "oil damper"....but an oil
> damper does not change the period, does it?
> To ask it in a different way......Picture the 36" vertical pendulum
> swinging in a large tube filled with air, Now the same pendulum, but with
> the tube filled with water.
> Would this change the resulting period?
> Thanks, Ted
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