Why does toilet water spin

A few years later, another research team at the University of Sydney showed the opposite to be true in the Southern Hemisphere. But when it comes to which direction flushed toilet water drains, only one thing matters do your flush jets point to the left or the right?

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Thanks for signing up! Check your inbox for a welcome email. Email required. By signing up, you agree to our Privacy Notice and European users agree to the data transfer policy. For more newsletters, check out our newsletters page. It sounds true. Just like Lisa explains to Bart, the Earth is subject to Coriolis forces , which determine how moving objects are deflected off the inside of rotating objects—wheels, circular containers, those kinds of things. Applied to Earth's rotating sphere, the Coriolis effect accounts in part for why, say, hurricanes and cyclones rotate the way they do.

The storms rotate c ounterclockwise in the Northern Hemisphere and clockwise in the Southern. In , Scientific American asked Brad Hanson, a staff geologist with the Louisiana Geological Survey, to explain in theory how those forces could affect drains. He replied that Coriolis effects:.

Here's the catch, though. Coriolis forces are best observed at a large scale; toilet water, in so many ways, is small-scale. As Robert Ehrlich, a physicist at George Mason University, explains it : " The effects of the rotation of the earth are, of course, much more pronounced when the circulation covers a larger area than would occur inside your bathtub.

So what does account for the varying ways that toilets flush and drains drain? The design of the objects that do the flushing and the draining, for the most part.