Re: "Faraday's Disk" which started it all

[Bob Sciamanda <trebor@VELOCITY.NET>]

Before I am consumed in flames, let me correct an error in terminology :  in
my last post (below) replace the word "meniscus" (which occurs even in
stationary water) with something like "the curved parabolic(?) surface".
I'm sure you know the phenomenon to which I am (poorly) referring and the
point involved.

-Bob

Bob Sciamanda
Physics, Edinboro Univ of PA (em)
trebor@velocity.net
http://www.velocity.net/~trebor

----- Original Message -----
From: Bob Sciamanda <trebor@VELOCITY.NET>
To: <PHYS-L@LISTS.NAU.EDU>
Sent: Saturday, July 03, 1999 1:02 PM
Subject: "Faraday's Disk" which started it all


> Hi William,
> I think I need to emphasize a point:  There is a measurable difference
> between relative rotation and "absolute" rotation (take this latter phrase
> to mean rotation relative to the fixed stars).  To paraphrase Mach, you
can
> only produce a curved meniscus surface in a pail of water by rotating the
> water in  this "absolute" sense; you will not observe this meniscus if you
> leave the water still and put only yourself into a spin, while standing on
> the extended axis of the pail.  The spinning water develops a meniscus
only
> when IT is rotating, whether you are rotating or not.
> . . .