Why Does Water Go Down the Drain Counterclockwise?

The Coriolis force is caused by the earth's rotation. It is responsible for air being pulled to the right (counterclockwise) in the Northern Hemisphere and to the left (clockwise) in the Southern Hemisphere. The Coriolis Effect is the observed curved path of moving objects relative to the surface of the Earth.

Why does water flush differently on the equator?

This effect is caused by the mismatched speed of the Earth's rotation: The equator is wider than the poles of the Earth, so points on the equator have to move faster to make one rotation in a day.

Why does water spin the other way in Australia?

Because of the rotation of the Earth, the Coriolis effect means that hurricanes and other giant storm systems swirl counter-clockwise in the Northern Hemisphere, and clockwise in the Southern Hemisphere. In theory, the draining water in a toilet bowl (or a bathtub, or any vessel) should do the same.