Water goes down the shower drain clockwise in North America and anticlockwise In South America. How do we call the phenomenon?

The Earth's rotation means that we experience an apparent force known as the Coriolis force. This deflects the direction of the wind to the right in the northern hemisphere and to the left in the southern hemisphere. This is why the wind-flow around low- and high-pressure systems circulates in opposing directions in each hemisphere.

The Coriolis effect was described by the 19th-century French physicist and mathematician Gustave-Gaspard de Coriolis in 1835. He formulated theories of fluid dynamics through studying waterwheels, and realized the same theories could be applied to the motion of fluids on the surface of the Earth.

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58 Comments

John Moore

In actual fact there is no truth in this at all. The Coriolis effect is too weak to make any difference. It's been demonstrated many times that water goes down a hole depending on the shape of the item it is running out of. It is a myth

Julie Allen

The influence of the Coriolis force on spin direction is real, but it is generally only observable on very large scales, such as trade winds and hurricanes. The affect the Coriolis force has on a toilet bowl is much too small to actually see in a flushing toilet but that doesn't mean that it doesn't exist.

dick aspel

Anticlockwise indeed exists- and we invented English after all.

timwhitestevens

Carroll Price, I agree.

timwhitestevens

David Wilhite, I agree.

timwhitestevens

Julie Allen, That is because toilet bowls have a predetermined direction as indicated by their jets, or usually straight down. If you fill a large sink, that does not have a preferential disposition, you will see a whirl pool that spins in the direction determined by the coriolis force. This is the same direction that the earth rotates; counter clockwise in the northern hemisphere, and clockwise in the southern hemisphere. (The question got the directions backwards.) Try it.

timwhitestevens

John Moore, I disagree, as long as the container does not have any predetermined shape. I have tried this by letting the water out of a large sink that was full of water. The direction of the whirlpool in the United States was counter clockwise and in Australia was clockwise. Try it. (The question got the directions backwards.)

timwhitestevens

Except you got it backwards; it goes counter clockwise in the northern hemisphere and clockwise in the southern hemisphere. This is because the earth rotates counter clockwise in the northern hemisphere and clockwise in the southern hemisphere. This is the same with hurricanes. On the equator it does not rotate and goes straight down.

Dragon Rebel

It's a force!

David Wilhite

You got it backwards, counterclockwise in the Northern Hemisphere it is based angular momentum.

teresab

New Yorkers waste water in the southern hemisphere watching the direction of the water.

Carroll Price

The explanation is wrong (backwards). In the northern hemisphere, water down drains (commodes, funnels, sinks) rotates in a COUNTER CLOCKWISE direction, as do hurricanes and wind directions revolving around low and high pressure systems. With the reverse holding true in the southern hemisphere.

Jim Adams

Funny I just call it water going down the drain.

Caroline Wolter Hall

John Moore, Reading Wikipedia are we? why is it that people who are SO WRONG have the biggest mouths??? It is a thousand percent true! Half my friends are in Australia. Is it a myth too that while we're having winter, they are having summer? Coriolis Effect from National Geographic. https://www.nationalgeographic.org/encyclopedia/coriolis-effect/ Coriolis Effect by NASA - I suppose they're wrong as well. https://www.nasa.gov/stem-ed-resources/coriolis-effect.html