According to a common opinion, the direction of twisting of water in the sink depends on the hemisphere in which it is located. The effect is associated with the rotation of the Earth and the action of the power of the Coriolis. We checked whether this is so.

If the effect really takes place, then you can determine whether the equator crossed the sink by continuously observing water in the funnel. In Soviet literature, this idea has gained popularity after academician Dmitry Grave in the journal “I want to know everything” (No. 4, 1931) wrote:

“If you release water from the tank using a hole at the bottom of it, then a funnel -shaped vortex is formed, which in the northern hemisphere rotates to the side, the reverse movement of the clockwise; In the southern hemisphere, rotation goes the other way. Each reader himself can check the justice of what has been said by releasing water from the bath. To better notice the direction of rotation of the vortex funnel, you can throw small scraps of paper on it. It turns out a spectacular experience proving the rotation of the Earth, produced by the simplest means in a home environment. ”

The famous popularizer of science Jacob Perelman became interested in the publication, who in 1932 organized an experiment with the assistance of his readers. Everyone had to trace a dozen times in which direction the funnel rotates when water flowing out of the bath, washbasin and similar tanks, and send a message to Perelman how many times there was a rotation counterclockwise. How Concluded Perelman, "the predominance of rotation aside counterclockwise was not seen."

The Western layman is known in many ways thanks to the multi -part documentary film “From Pole to Pole with Michael Paylin” (1992). It has a certain resident of the Kenyan city of Nanyuki I tried Demonstrate the focus on opposite sides of the equator. Oddly enough, the direction of circulation turned out to be the opposite calculations of Academician Grave, but this did not embarrass the audience: on the contrary, millions of people believed in a wonderful property.

The question arises: if there is such an instability of experimental results, is the theory itself true? Firstly, we will get acquainted closer to the concept of the power of Coriolis. This is an inertial force that acts on a material point when moving a relatively rotating dedication system (in this case, planet Earth). It forces objects moving along the surface of the Earth to deviate to the right in the northern hemisphere and to the left in the southern. In the case of flowing along an inclined concave surface, this will give a movement against and clockwise, respectively.

But there is a very important factor - the degree of influence of this force. And it depends, on the one hand, on the shape of the funnel and adjacent surfaces, on the other, on the parameters of the stream and latitude (the so -called number of Rossby). In other words, the smaller the scale of the flow and the closer to the equator we are, the more microscopic the influence of the Coriolis force against the background of other forces. Therefore, do not hope for a stable operation of the effect at the equator. Like in general for success in a regular bathroom.

But in laboratory experiments in compliance with the maximum number of conditions (symmetry of the shape of the vessel, sucks in front of the drain, almost complete absence of air movement, removal from the equator) often everything worked correctly: in both hemispheres, the water received the right rotation. Here is an example of a classic experiment conducted in the United States back in the 1960s:

As you can see, twisting water depending on the hemisphere only works in special conditions. This effect is almost completely torn off from life. Therefore, despite the correct theoretical base, in an arbitrary case, such experiments will almost always be doomed to failure.