Saturday, November 15, 2008
A surprising large number of people have asked me whether the toilets really do flush in the opposite direction in the Southern Hemisphere, due to the Coriolis Effect. Well, the toilets I've seen in Australia don't swirl at all; there is a short but powerful swoosh of water that lasts only a second or two, with no rotation.
According to The Straight Dope, Snopes.com, and other authorities, the whole swirling-the-opposite-way thing is a myth. Any rotation of water in a toilet, bathtub, sink, etc. is due to previous motion of the water, or direction of a water jet, or shape of the bowl, or other mundane reasons.
But it is true that if you let go of something, it falls up into the air, because we're upside down. I never would have guessed that was true.