monkaaay

While commuting home from the grocery last night I found myself looking to the clouds and pondering the subject of toilets. I remembered my father's wise words about the clockwise-counterclock-wise age old ponderence... "If toilets flush clockwise in the northern hemisphere, do they flush counter clock wise in the southern hemisphere?" Having never been to the southern hemisphere I have not been able to experience this privy phenomnon for myself, leaving me commode curious.

So I did some researching and I have NOT found the answers. All information is contradictory. I'm not sure what to believe.

First we need to know about the Coriolis force-
Coriolis effect: (as related to the rotation of Earth) Moving objects on the surface of the Earth experience a Coriolis force, and appear to veer to the right in the northern homisphere, and to the left in the southern.

So that explains hurricanes spinning different directions in the northern and southern hemisphere. "If a low-pressure area forms in the atmosphere, air will tend to flow in towards it, but will be deflected perpendicular to its velocity by the Coriolis acceleration. A system of equilibrium can then establish itself creating circular movement, or a cyclonic flow." (from Wikipedia) "In the Northern Hemisphere the direction of movement around a low-pressure area is counterclockwise. In the Southern Hemisphere, the direction of movement is clockwise because the rotational dynamics is a mirror image there. " (also Wikipedia)

That's not the question here though, that just shows that the Coriolis effect exists, but now how do we apply it to the bathroom? Well most of the things I have read say that the scale of cyclones is so large that the Coriolis effect does matter, but in the bathroom the scale is too small. All articles I have read say that the reason there is a rotation is not the Coriolis effect, but rather water shooting into the toilet at an angle, or the inperfections in the surfaces.

"In a very carefully controlled experiment to remove all other forces from the system, rotation could conceivably play a role on scales as small as a bathtub. ... As shown by Ascher Shapiro in a 1961 educational video called Vorticity, Part I, this effect can indeed reveal the influence of the Coriolis force on drain direction, but only under carefully controlled laboratory conditions. In a large, circular, symmetrical container (ideally over 1m in diameter and conical), still water (whose motion is so little that over the course of a day, displacements are small compared to the size of the container) escaping through a very small hole, will drain in a cyclonic fashion: counterclockwise in the Northern hemisphere and clockwise in the Southern hemisphere — the same direction as the Earth rotates with respect to the corresponding poles." (from Wikipedia)

So it IS possible to get the effect to take place on a small scale, but all other variables have to be perfect.

"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 spin given to water draining from sinks and bathtubs to a degree that overwhelms the slight influence of the Coriolis effect." (from Snopes)

So after reading all of that I thought I had found the answer... toilets are not affected by the Coriolis effect and spin the way they do because of other reasons... But I'm not convinced. So please weigh in so we can figure this out! It is important for all man kind to know the answers behind the toilet!