RE: How come the water is turning counterclockwise ??

On the surface of any astronomical body that is turning appears asymmetries - "left symmetry" in one hemisphere and "right symmetry" in the other one. For example: if you are inside an aircraft in the north hemisphere and flying straightaway to the north pole, you should be correcting the trend of the aircraft to deviate to the right (of course looking at the pole). On the other hand, if you are flying in the southern hemisphere, towards the south pole, the deviation is left-handed. These deviations are examples of an effect called Coriolis. Coriolis effect is the deflection of a body in motion with respect to the earth as seen by an observer on the earth. Coriolis effect is attributed to a hypothetical force, Coriolis force, which is actually caused by the earth's rotation. The effect's name is in honor of Gaspard G. Coriolis (died 1843), a French civil engineer.

In both the northern and southern hemispheres, the Coriolis deviation is towards the east when an object is moving towards the pole. It is towards the west, when an object moves towards the equator from the noth pole. The Coriolis effect plays an important role in the atmospheric and oceanic currents.

Well, it is very difficult to say if the Coriolis force is so strong as to be detected on the water. When it is drained through an outlet, the water forms a spiral, a vortex moving around the outlet.

What are the explanations for this phenomenon? Imagine a wide and circular bathtub with a planar bottom, that is placed on the north pole. When the water flows toward the hole (outlet placed in the bathtub center), the Coriolis force deviates the water in a counterclockwise direction. A whirpool is formed. On the south pole the phenomenon is inverted. Really the water takes an eastward direction, but now the deviation produces a whirpool in a clockwise spiral. The water's trend to form a spiral is marked on the poles and is not notable when we go to the equator, where the trend disappears. Some trials showed the Coriolis effect in the outlet of the bathtub and it is possible to detect this effect. A. H. Shapiro, a physicist at Mississipi's Technology Institute developed several experiments with a circular bathtub of two meters of diameter. He filled the bathtub with water and let the water rest for several days. When he pulled the drain plug, a persistent counterclockwise whirpool appeared. He credited this phenomenon to the Coriolis effect. Another scientist, Merwin Sibulkin wrote a paper titled "Note About of Bathtub's Vortex" (Journal of Fluid Mechanics, Sep/ 1962, pages 21-24), but he was not successful in his experiment, probably because he used a small bathtub.

Shapiro's experiments were confirmed in 1965. Five scientists at Sydney University (Scientific American, Nov. 1965 page 54). For over 18 hours they let water rest in a circular bathtub. When it was drained, they saw dextro vortices. They said "we have self-confidence in the hypothesis that the experiment of drain liquids toward a deposit shall produce vortices in clockwise if the experiment is realized on the austral hemisphere."

Coriolis effect is responsible for a tornado's trends to turn counterclockwise in the northern hemisphere and clockwise in the southern hemisphere.

With reference to the bathtub's vortex, the questions are still under discussion, and it's necessary to perform more careful experiments, with a big bathtub and good observations before arriving at a final verdict.