In the southern hemisphere does water really spin clockwise down the plughole and anti-clockwise in the north?

Question

In the southern hemisphere does water really spin clockwise down the plughole and anti-clockwise in the north?

Answer 1

You can start the spin either way and it will be sustained by momentum of the liquid.  The Coriolis force is relatively weak especially for small diameters (but very powerful in organizing hurricanes 100s of miles across that spin in reverse on opposite sides of the equator).  That said, a very large tank was shipped from North America to South America that had a drain on the bottom to feed the inlet of a centrifugal pump.  The pump failed to operate properly (cavitated) because 'flow straighteners' at the tank discharge were designed for the spin of the northern hemisphere rather than the southern hemisphere.  You are correct but other factors may easily override the Coriolis effect.

Answer 2

No, it's a myth.

Answer 3

I read that eddy currents last several days.  So spin the water one day and a couple days later it should still spin  in that direction when you let it down.  haven't tried

Answer 4

Yes it is true.  This is due to the rotation of the earth.

Answer 5

No the forces that that is attributed to are too small. Water is much greater influenced by conservation of motion and some initial random fluid movements. You can find out more at:

http://en.wikipedia.org/wiki/Coriolis_ef...

Answer 6

Yes. And no.

The direction of motion is caused by the Coriolis effect. This effect is the basis of the Foucault pendulum demonstration and also causes cyclones in the northern hemisphere to rotate counterclockwise. However, this effect is so weak that most of the time the direction of spin of draining water is random.

To observe the true Coriolis effect you would need to have a symmetrical basin of water completely at rest. The basin must be in an extremely stable area with no vibrations and the water must sit for a long time, say a week, to be sure there are no remaining currents. Then the plug must be removed in such a way as not to disturb the rotation. Then the water would spin counterclockwise in the northern hemisphere, clockwise in the southern.

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Answer 7

It is utter nonsense

And a very old prank that we sailors play on newcomers who join our ship

Whenever we are crossing the equator - we tell them to make this "fascinating" observation

Some of them even have their video cameras ready

Its hilarious!!!

Answer 8

No.  The direction depends upon the way the vessel is built and the piping, and that's regardless of any elegant explanations attempting to account for something that's nothing more than a widespread myth.