Watch water swirl down the drains of different sinks and tubs. Does the water turn the same direction (clockwise or counterclockwise) in each one? Can you make it go the other way by stirring?
The water may have swirled clockwise down one drain and counterclockwise down another. Stirring can often make it go either way.
It's often said that water goes down counterclockwise in any drain that's north of Earth's equator--and clockwise south of the equator. The idea comes from the fact that Earth's spin makes big, slow wind systems turn in these directions. North of the equator, hurricanes and cyclones turn counterclockwise. Those to the south turn clockwise.
But the force of Earth's spin works only on slow-turning systems. On fast systems, other things have greater effects--such as the shape of the drain or small currents left over from filling the basin.