However I did an experiment when I was on a trip to Kenia ( Country split by the equator). I used a bottle with a very small hole in it, and filled it with water and a little piece of water. The I opened the hole and the water run out. The wooden piece start rotating in the water. I repeated this several times and the direction was the same. Then I did the test at the other side of the equator, a few 100 km away, with the same material and the rotation was opposite! Coincidence?