2006-11-16 06:24:28 · 12 answers · asked by Colin W 1 in Science & Mathematics ➔ Geography
Contrary to popular myth, a bathtub or washbasin is far too small to feel the effects of Coriolis forces. The direction of spin for a drain whirlpool is therefore determined (in both hemispheres, at all latitudes) by the presence of small undamped residual currents in the basin or tub, that were in most cases created when the basin was filled.
2006-11-16 06:29:33 · answer #1 · answered by Keith P 7 · 1⤊ 0⤋
You're thinking of the Coriolis effect, which causes things like hurricanes to rotate clockwise in the southern hemisphere, and anti-clockwise in the northern hemisphere. It does apply to water going down the plughole, but the effects are very very small, and are cancelled by other effects such as the shape of the basin. An experiment to prove this is to fill a basin with water, and let it settle for a while. When you see no more movement on the surface, swirl the water clockwise, then leave it to settle again. When the surface is till, pull the plug out, and the water will go down the plughole clockwise. If you repeat this, but swirling the water anti-clockwise, the water will go down the plughole anti-clockwise. Try it!
2006-11-16 06:40:47 · answer #2 · answered by drummanmatthew 2 · 0⤊ 0⤋
No particular direction. The idea that water goes down the plughole in different directions depending on the hemisphere you're in is an urban myth.
The Coriolis Effect (on which this myth is based) only works on large masses of water and air. This effect means that similar weather systems spin in opposite directions in different (North-South) hemispheres.
The main factors affecting the direction of the plughole vortex are:
Manufacturing process for the sink/bath
Material used to make the sink/bath
The shape of the plughole
The manner in which the plug is removed
You can sometimes change the direction of the vortex by disrupting it with a hand or foot.
2006-11-16 06:37:27 · answer #3 · answered by Anonymous · 2⤊ 0⤋
Straight down no spin
Its true that the Coriolis forces are not powerful enough to have a big effect on such a small amount of water but it does work well enough to see a trend of clockwise or anticlockwise
2006-11-19 20:53:18 · answer #4 · answered by xpatgary 4 · 0⤊ 0⤋
it is not defined and can go either way, I saw a David Bellamy program on tv years ago and they showed it live a number of times and it was not always the same way but they moved a couple of hundred yards north and south and the direction was consistant for each hemisphere.
2006-11-16 06:32:05 · answer #5 · answered by torbrexbones 4 · 0⤊ 0⤋
It depends entirely on the shape of your sink and not whether you are in the northern or southern hemisphere.
2006-11-16 06:41:54 · answer #6 · answered by Mr Cheese 3 · 0⤊ 0⤋
Down. Same as any othe location that has gravity.
2006-11-16 06:28:16 · answer #7 · answered by sudonym x 6 · 0⤊ 0⤋
Apparently it goes straight down!
2006-11-16 06:26:15 · answer #8 · answered by Funky Little Spacegirl 6 · 0⤊ 1⤋
straight down
2006-11-16 06:27:25 · answer #9 · answered by ribble_girl 2 · 0⤊ 1⤋
A.M. clockwise P.M. anti clockwise
2006-11-16 06:32:19 · answer #10 · answered by ? 4 · 0⤊ 2⤋