Friday, July 11, 2014

From Bathtubs to Hurricanes

This is Erik, I'm from around here, and I go to Emerson college. I'm also working on some riverboats for the spring/summer/fall seasons, but I work at an vocational training non-profit during the fall and winter.

My observation was that the sink drained in a counter-clockwise pattern. I tested this at home a few times, and i one sink it seemed to drain counter-clockwise while the other drained clockwise. The sink that drained clockwise, however, ended up having a slight curve to it, which I believe affected the flow of water. Also, in retrospect, the way in which I unplugged the sink (with my hand) might have an effect on the spin of the water.

In theory, the apparent pull of water due to its position on earth is known as the Coriolis effect. A fluid spinning on a rock in space seems to  be moving as if spinning counter-clockwise in the northern hemisphere and clockwise in the southern hemisphere. However, this effect is only important to planes and rockets going over massive distances or for hurricanes and other hemisphere-wide events. It is negligible for one's own sink, to which the Coriolis effect is hard to measure or observe.

As an answer to the question, I say: "Yes, there should be an opposite spin (all variables controlled for) in the USA to Australia, but in reality it's hard to remove all variables such as faucet giving the water a spin or the shape of the sink."

Sources:

http://math.ucr.edu/home/baez/physics/General/bathtub.html
http://www.loc.gov/rr/scitech/mysteries/coriolis.html
http://www.ems.psu.edu/~fraser/Bad/BadCoriolis.html

...and some good old staring at a sink.

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