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From: steve@jplgodo.UUCP (Steve Schlaifer x3171 156/224)
Newsgroups: net.physics
Subject: Re: The wild ride down the drain... (Coriolis force)
Message-ID: <536@jplgodo.UUCP>
Date: Sun, 22-Dec-85 20:43:49 EST
Article-I.D.: jplgodo.536
Posted: Sun Dec 22 20:43:49 1985
Date-Received: Wed, 25-Dec-85 01:41:13 EST
References: <50@decwrl.UUCP> <677@hou2b.UUCP>
Organization: Jet Propulsion Labs, Pasadena, CA
Lines: 16

> Contrary to what many have claimed, the coriolis force does exert
> a real influence in determining the direction of spiral down the
> drain.  This fact has been experimentally shown many times.  There
> is a short film I saw in Fluids class or Frosh Physics umpteen years
> ago that recorded one of these experiments.  A large tub was filled
> so that the induced motion would be contrary to the expected motion.
> The tub sat undisturbed for hours.  When a plug was pulled, the water
> eventually spiraled the way expected.  The experiment was repeatable.

The above mentioned experiment is incomplete.  All it *proves* is that the
water in the tub in question spiraled out in the *expected* direction.  It
is still possible that the spiraling was due to small imperfections in the
tub itself which caused a preferred spiraling direction.  What is needed for
this to be a more complete demonstration is to take the tub to the other
hemisphere and repeat the experiment there.  If the direction of spiral
reverses then a good demonstration of the effect has been made.