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From: bobm@rtech.UUCP (Bob Mcqueer)
Newsgroups: net.physics
Subject: Re: Re: The wild ride down the drain...
Message-ID: <792@rtech.UUCP>
Date: Sun, 15-Dec-85 13:20:57 EST
Article-I.D.: rtech.792
Posted: Sun Dec 15 13:20:57 1985
Date-Received: Tue, 17-Dec-85 04:00:36 EST
References: <757@alberta.UUCP>
Organization: Relational Technology, Alameda CA
Lines: 32

> 
>> Does this phenomenon have anything to do with the Corealis (sp?) force?
> 
> No - It has to do with conservation of angular momentum.
> 
> Given a circular tub with a drain hole in the middle.  Water draining out
> of that hole will almost always form a whirlpool but that is because the
> body of water almost always has some initial (albeit small) angular momentum
> about the hole which determines the direction.
> 
> Don't take my word for it.  There is nothing like a good experiment to 
> debunk this sort of nonsense.  The tub I tried it on was circular with the

seconded.  I just now went to the bathroom sink, filled it a few times, and
by swishing the water around in different directions before opening the drain
managed to induce whirlpools in both directions.  Also observe that if you do
this the whirlpool forms a lot sooner than in a still sinkfull of water.  Of
course, to be sure I wasn't cancelling out the "corealis" effect, I would
have to do some more rigorous experimenting, but ....

What I wanted to add was that this little tale is usually told concerning
toilets, and if you look, the water coming out from under the lip of the
bowl is usually sent out at a slant, inducing a very definite direction for
the whirlpool (for good design reasons, probably - think about it).  If
there WERE any differences between hemispheres, this would certainly cancel
them out.  I wouldn't be surprised if the tale got started because makers of
toilets in different countries slant the water jets in different directions
for some arcane reason, or more likely, because clockwise was as good as
counterclockwise, and somebody flipped a coin.

Bob McQueer
ihnp4!amdahl!rtech!bobm