[Stoves] coriolis or simple inertia

[Jeff Forssell]

Having been a physics teacher, I know that a certain amount of "sleight of hand" is useful to "demonstrate" some things that are either too subtle to notice on top of other effects or require equipment or preparation outside the scope of the school lab. (I feel less sympathy with that approach the more I notice bad science corrupting people's view of reality. Like "polio vaccine stopped the epidemic.")

I suspect that your clever equator fellow used some subtle manipulation, (how he "pulls the plug" perhaps? Some little twistable vane in the drain pipe?) Even a very slight rotation in the water is magnified as the radius of the water mass decreases (like spinning skaters).

See even: http://en.wikipedia.org/wiki/Coriolis_effect#Draining_bathtubs.2Ftoilets

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Jeff Forssell
Fil.Lic. i Fysik
HÄRNÖSAND /Sweden

> Some are saying that hole direction has no effect but in western
> Uganda there is a spot along the main road where you cross over the
> equator. Some enterprising chap has managed to assemble a simple
> basin with a 20mm hole in the bottom. HE locates the basin and stand
> abut 15 ft to one side of the equatorial line, plugs the hole and
> fills the basin. He inserts his hand to quiet the water, carefully
> removes his hand leaving a non-moving floating twig in its stead. He
> then pulls the plug the water soon assumes a certain rotation and the
> basin drains accordingly. He repeats it 15 ft to the other side of
> said line and voila, it flows the opposite direction. I tried it
> myself with same results. I repeated it right on the said  line and
> the rotational motion did not ensue in either direction.
> Now this is a solid and it is obeying laws of inertia so we may be
> seeing an entirely different phenomena at work ..what sayest thou all
> about that.