Sunday, December 20, 2009

Why water turns clockwise in a wash basin in the southern hemisphere and the other way in the northern hemi?

Actually its called the Coriolis effect and junglist is right


Draining bathtubs/toilets


A popular misconception is that the Coriolis effect determines the direction in which bathtubs or toilets drain, and whether water always drains in one direction in the Northern Hemisphere, and in the other direction in the Southern Hemisphere. The Coriolis effect is a few orders of magnitude smaller than other random influences on drain direction, such as the geometry of the sink, toilet, or tub; whether it is flat or tilted; and the direction in which water was initially added to it. If one takes great care to create a flat circular pool of water with a small, smooth drain; to wait for eddies caused by filling it to die down; and to remove the drain from below (or otherwise remove it without introducing new eddies into the water) – then it is possible to observe the influence of the Coriolis effect in the direction of the resulting vortex. There is a good deal of misunderstanding on this point, as most people (including many scientists) do not realize how small the Coriolis effect is on small systems.[1] This is less of a puzzle once one remembers that the earth revolves once per day but that a bathtub takes only minutes to drain. When the water is being drawn towards the plughole, the radius with which it is spinning around it decreases, so its rate of rotation increases from the low background level to a noticeable spin in order to conserve its angular momentum (the same effect as bringing one's arms in on a swivel chair making it spin faster).Why water turns clockwise in a wash basin in the southern hemisphere and the other way in the northern hemi?
Thanks, sorry junglist I thought you deserved the points I was just trying to add on to your post Report Abuse
Why water turns clockwise in a wash basin in the southern hemisphere and the other way in the northern hemi?
its called the coreolus (sp) effect
It doesn't - its a myth.





You can find both counterclockwise and clockwise flowing drains in both hemispheres. Some people would like you to believe that the Coriolis force affects the flow of water down the drain in sinks, bathtubs, or toilet bowls. Don’t believe them! The Coriolis force is simply too weak to affect such small bodies of water.





In his work “Sur les equations du movements relative des systems des corps” (1835) the French engineer Gaspard Gustav de Coriolis (1792-1843) first described this force. The Coriolis force is caused by the earth’s rotation. It responsible for air being pulled to the right (counterclockwise) in the Northern Hemisphere and to the left (clockwise) in the Southern Hemisphere.





The Coriolis Effect is the observed curved path of moving objects relative to the surface of the Earth. Hurricanes are good examples. They curve to the right in the northern hemisphere and to the left in the southern hemisphere. What makes the hurricanes move in this way is the Coriolis force.





What happens at the equator? The Coriolis force is too weak to operate on the moving air at the equator. This means that weather phenomena such as hurricanes are not observed at the equator, although they have been observed at 5 degrees above the equator. In fact, the Coriolis force pulls hurricanes away from the equator.
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