In which direction does the water swirl turn when you pull out the stopper from the bathtub?

Question

I am from germany and a fiew people say that it depends of living in the north or the south half of the earth. My swirl turns clockwise, does an australian swirl really turn unclockwise?
Sorry for the bad english.

Answer 1

Question: Does my bathtub drain differently depending on whether I live in the northern or southern hemisphere?

Answer: No. There is a real effect, but it is far too small to be relevant when you pull the plug in your bathtub.

Because the earth rotates, a fluid that flows along the earth's surface feels a "Coriolis" acceleration perpendicular to its velocity. In the northern hemisphere, Coriolis acceleration makes low pressure storm systems spin counterclockwise; however, in the southern hemisphere, they spin clockwise because the direction of the Coriolis acceleration is reversed. This large-scale meteorological effect leads to the speculation that the small-scale bathtub vortex that you see when you pull the plug from the drain spins one way in the northern hemisphere and the other way in the southern hemisphere.

But this effect is VERY weak for bathtub-scale fluid motions. The effect of the Coriolis acceleration on your bathtub vortex is SMALL. To detect its effect on your bathtub, you would have to get out and wait until the motion in the water is far less than one rotation per day. This would require removing thermal currents, vibration, and any other sources of noise. Under such conditions, never occurring in the typical home, you WOULD see an effect. To see what trouble it takes to actually see the effect, see the reference below. Experiments have been done in both the northern and southern hemispheres to verify that under carefully controlled conditions, bathtubs drain in opposite directions due to the Coriolis acceleration from the Earth's rotation

Answer 2

Opposite the earth's rotation.

If you view the water drain "towards the equator" then the northern hemisphere will view it "from the top" seeing an apparent clockwise rotation, and the southern hemisphere will view the exact same rotation "from the bottom". This assumes that you consider the North Pole as the top of the world.

Coriolis effect does not truly apply to a purely bathtub scenario.

Which way does a clock's hands rotate if you view the clock from the back?

This would give rise as to why Eurasian cultures have chosen "clockwise" as being the same as a northern hemishpere water drain.

We have also standardized our screws and bolts this way.

Answer 3

Your English is excellent! Although people argue that water goes down the plughole anti-clockwise in the northern hemisphere and clockwise in the southern hemisphere, this is a myth based on the way winds deviate from a straight path because of the rotation of the earth. In practice, the forces caused by deceleration when the water flows down the plughole for a few metres are so minuscule that they have no effect on the direction of water flow, whereas winds are travelling many hundreds of kilometres and therefore the effect of the earth's speed being different at different latitudes is significant. The more likely cause is the shape of the wash-basin. We have 5 wash-basins and two sinks at home, and the direction of water flow is NOT uniform.

Answer 4

Yes, I am from the United States and ours turns clockwise.

I had a friend that lives in Aulstrailia and it turnes counter-clockwise.

This is known as the Coriolis Effect.

Exerpt from Source 1:

[edit] 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. In reality, 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. Note that toilets typically are designed to only flush in one rotation, by having the flush water enter at an angle.

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 drain, 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 ice skaters bringing their arms in to cause them to spin faster).

Hope this helps!

Answer 5

Due to the Coriolis Effect, in the northern hemisphere the water will swirl clockwise, in the southern hemisphere it will swirl counter-clockwise.

For a reason why, check this link:
http://en.wikipedia.org/wiki/Coriolis_effect

Answer 6

It depends on where you live. Do to the pull of gravity. I live in the US and our water swirls counter-clockwise.

Answer 7

I live in United States and mine flow's clockwise

Answer 8

i think it is a scientific bullshyt. like watching the stars from the bottom of a deep well. there are many prejudices in science as well. i tried to prove this or that and was no success.

Answer 9

ya it depends on where you are.
in northern hemisphere: anti- clockwise
in southern hemisphere: clockwise

same happens with tropical revolving storms

Answer 10

Clockwise no matter where you are ...