# Why does the toilet water in the Northern Hemisphere always swirl counter clockwise??

Seriously, why

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It doesn't necessarily do that!

There is a very weak overall APPARENT force called the "Coriolis effect." You see, we are acted upon by the gravity of the earth, but the earth is spinning on its axis once a day and also rotating around the sun. So, away from the earth, you'd see not a "line" of gravity from you to the center of the earth but a CORKSCREWING MOTION as the earth spins and rotates about the sun.

Given BIG ENOUGH matter (say all the clouds in 1 million miles of Atlantic Ocean) over enough time (say 10 days as a storm develops), you will see the clouds form and swirl counterclockwise because of the Coriolis effect. Yes, the storms south of the equator swirl the other way.

You can demonstrate this in a basin, too -- if!-- the basin forms a perfect hemisphere with very smooth sides and the drain is at the very center of the hemisphere --and! -- if you give it enough time for the random motion of the water to cease (and that will be about a week!) --and!-- if you drain the water out with a tiny, itty-bitty pin hole.

Otherwise you will "lose" the tiny Coriolis effect in the large random motions of the water molecules, the asymmetry of the container and the large size of the drain hole.

The water in your toilet swirls because the water is directed to come out AT AN ANGLE below the rim, and as it squirts down it creates a swirl, by design. The same is true of your washbasin and kitchen sink because the DESIGN of the sink is not symmetrical, it's designed to swirl water away.

There is an actual Coriolis effect, but it is too tiny to measure unless we set up very quiet, still conditions to observe it fairly.

Actually, the holes under the lip of the toilet bowl are made to cause the water to swirl that way.We need the water to swirl down like that so it drains properly.I'm not sure if they make it swirl clockwise in the Southern Hemisphere.It would be interesting to know though.

wow... i can't insult you 'cos sooner or later i'd wonder the same thing; my mind works in strange ways

does it swirl clockwise in the southern hemisphere?..

do i even want to know?

so, did you just come up with this question one day out of the blue, or is there some sort of discussion group i should know about