Date: Sat, 29 Apr 2000 23:01:53 -0700

Author: "Bernard G. Cleyet & Nancy Ann Seese"

Subject: Re: Ghost forces

Post:

I can't believe it -- you are all experimentalists? Has any one calculated the
non-existent (frame) force on a mL of water moving towards a drain at some reasonable
speed, yet? Is it reasonable to expect it to be greater than what an expected asymmetry in
the sink or the unplugging of the drain would be? (Surely much greater than any
butterfly.)

bc

P.s. try 206.186.163.160/article.cfm/astronomy/24987 claims to be a site that debunks
kitchen sinks. That server refuses -- maybe you'll have better luck.

Urs Lauterburg wrote:

> Glenn et al.
>
> I believe this problem is still not 100% resolved and of course a
> superposition of a variaty of effects including the butterfly one. However
> one way to prove that there is some truth to this physical myth would be to
> stage a statistical experiment. You would have to construct a precision
> sink, put it in a box of constant temperature and use pure distilled water
> at the same temperature. With this setup you would have to move to two
> different antipole positions of the same latitude on our globe and observe
> the vortex build up many thousend times of course keeping track documenting
> the results. This of course has to be done after statistical calibaration
> of the sink at either one of the poles or on the equator. It will probably
> be hard to get funding for such an experiment though. A person with no idea
> of the problem and what you are after would also consider you crazy
> encountering you sitting in a climatized box observing over and over the
> build up of a vortex in a sink and reporting the result in a large book.
>
> Anyway this is the aspect of physics I like most.
>
> regards
>
> Urs
>
> Urs Lauterburg
> Physics Edutainer
> University of Bern
> Switzerland
>
> >At 10:05 AM 04/28/2000 -0400, you wrote:
> >>Bad Spellers of the World, Untie!
> >>
> >>So what IS the reson for the swirlling of water as it goes down the drain?
> >>Or, better yet, why ISN'T the coriolis force responsible for this? I had
> >>always heard, unless the water is forced such as in a toilet, if you fill the
> >>sink with water, pull the plug and watch, you would see the coriolis force in
> >>action. In fact, I was going to use that as an example, so I'd really like to
> >>know!
> >>
> >>Chele
> >I had been taught that this coriolis force made the water draining from a
> >sink spin in one direction in the northern hemisphere and in the opposite
> >direction in the southern hemisphere. Sounded good to me. I almost always
> >believed my professors.
> >
> >Several years later I got to test this idea. I was on a ship that was
> >scheduled to cross the equator - down in the South Pacific. In fact, we
> >cut across the equator a whole bunch of times as we were assigned to be a
> >missile firing observation ship for a Trident missile launch. The oparea
> >we were assigned straddled the equator.
> >
> >A couple of us thought it would be cool to observe water sink drainage as
> >we crossed the equator. We did this for a total of five crossings. We
> >were very sad to discover that the rotation direction did not change as we
> >crossed the equator. Later we thought that it was kind of dumb to expect
> >that the equator could be that precise a thing - you know, your're in the
> >northern hemisphere and then, bang, you're in the southern hemisphere. So
> >we tested the thing down by New Zealand - observed the water drainage
> >direction (it was clockwise) and then observed it at a similar latitude in
> >the northern hemisphere.
> >
> >Damned if it wasn't clockwise as well.
> >
> >So who knows?
> >
> >Glenn
> >-----------------------------------------------------------------
> >Physics Kahuna
> >Kahuna Physics Institute - on the flapping edge of physics research.

Back