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n 1908, the Austrian physicist Otto Tumlirz described careful and effective experiments which demonstrated the effect of the rotation of the Earth on the outflow of water through a central aperture. The subject was later popularized in a famous article in the journal Nature, which described an experiment in which all other forces to the system were removed by filling a 6 feet (1.8 m) tank with 300 US gallons (1,100 l) of water and allowing it to settle for 24 hours (to remove any internal velocity), in a room where the temperature has stabilized. The drain plug was then very slowly removed, and tiny pieces of floating wood were used to observe rotation. During the first 12 to 15 minutes, no rotation was observed. Then, a vortex appeared and consistently began to rotate in a counter-clockwise direction (the experiment was performed in the Northern hemisphere, in Boston, MA). This was repeated and the results averaged to make sure the effect is real. The report noted that the vortex rotated, "about 30,000 times faster than the effective rotation of the earth in 42░ North (The experiments location)" Thus, the Coriolis effect does indeed play a role in vortex rotation for draining liquids that have come to rest for a long time and may be observed under carefully controlled laboratory conditions.
It usually isn't; it's a myth.
Quote from: Bored chemist on 23/05/2010 17:26:43It usually isn't; it's a myth.In terms of water going down plug holes, it does seem to be mostly mythology, but in terms of atmospheric conditions, it seems to be real enough.http://en.wikipedia.org/wiki/Anticyclone
Incidentally, I suspect that the North and South poles and the equator are the only places where the Coriolis effect wouldn't influence the water.