Whirlpool, a circular current of water with a depression in its center into which objects may be drawn and sucked down. A small whirlpool is sometimes called an eddy. A whirlpool is formed when an obstruction hinders the normal flow of a current or when water is stirred, such as when an oar is pulled through it.
Whirlpools are common on the downstream sides of rocks in rivers and at the bottom of waterfalls. They are formed also when currents moving in opposite directions sideswipe each other. Sometimes they occur when wind opposes a current. A whirlpool is formed also when water drains through a small hole, such as the drain of a wash basin.
There is no truth in the belief that whirlpools spin counterclockwise in the Northern Hemisphere and clockwise in the Southern Hemisphere.
