Does the coriolis force cause draining water to spin in opposite directions in the northern and southern hemispheres ?
As Snopes explains: The twisting effect of the Coriolis force is real and does influence certain large things like the movement of air masses, but the effect is so small that it plays no role in determining the direction in which water rotates as it exits from a draining sink or toilet. The Coriolis effect produces a measurable effect over huge distances and long periods of time, neither of which applies to your bathroom. Toilets and sinks drain in the directions they do because of the way water is directed into them or pulled from them. If water enters in a swirling motion (as it does when a toilet is flushed, for example), the water will exit in that same swirling pattern; as well, most basins have irregular surfaces and are not perfectly level, factors that influence the direction in which water spirals down their drains. The configuration of taps and drains is responsible for the direction of sp
