Whirlpool

A whirlpool is a body of water that is going round. It forms when water, which normally goes along, decides to go around instead, usually without warning and always either clockwise or anticlockwise.^[1]

Many of the largest whirlpools are caused by the tide squeezing through narrow channels, where the sea goes in a hurry and comes back in a circle.

The bath whirlpool

The small whirlpool that forms when a bath is drained is the most studied whirlpool in the world, having been observed by an estimated 4.1 billion researchers, most of them aged six. It is often said to spin one way in the north and the other way in the south. It does not: a bath is far too small for that, and the water simply turns whichever way it was already drifting when it made up its mind.^[2]

Measurements

• Width: one plughole to several kilometres.
• Rotation period: 4 to 400 seconds, a figure oceanographers describe as “tight”.
• Direction: round (±360°).
• Danger: high for small boats, moderate for rubber ducks, nil for the water, which is having a lovely time.

See also

• Bath – home of the most studied whirlpool
• Tide – the cause of the big ones
• Spiral – a whirlpool that has dried out

References

1. Eddy, C. (2001). Round and Round. Swirl Books. pp. 1, 1, 1.
2. Drayne, P. (2014). “Which Way Did It Go?” Bathroom Science Letters 9: 6.
3. Vortex, M. (n.d.). Going Around. Reprinted twice, in a loop.