Flushing water down the drain

In the northern hemisphere, when water flashes down a hole, it goes clockwise. On the Southern hemisphere, it goes counterclockwise. To understand how this works, recall that the Sun goes from east to west, which means that the Earth rotates from west to east. So, if you are standing on the North Pole, the Earth under your feet rotates counterclockwise, and that forces the water to flush in the opposite direction. If you are anywhere else in the northern hemisphere the Earth under your feet still rotates counterclockwise, so you're getting the same effect. Now, when you are on the South Pole, then the Earth under your feet rotates clockwise, which forces the water to flush counterclockwise. Likewise, when you're anywhere in the southern hemisphere. If you're exactly at the equator, then the Earth under your feet is not rotating at all and the water goes straight down. Water viscosity (i.e. friction of water against itself) is small enough for it to be sensitive to the Earth rotation. If you try the same thing with a more viscous fluid like honey, it will go straight down regardless of where you are located.