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Does water always swirl the same way down a plughole?
This must be in the all time top ten of science myths! Supposedly water in the Northern hemisphere goes down the plughole in one direction and in the Southern hemisphere it goes the opposite way.
People living on the equator even show tourists how just stepping over the equator can make this change happen. Surely there must be some truth in it. Well, sort of…
If you took two identical sinks in the UK and in Australia and did an identical experiment in both places (every aspect of the experiment would need to be completely identical!) then it is likely that the water will go one way in the UK and the opposite way in the sink down under.
However, lots of other factors - such as the shape of your sink, how you pulled the plug out, even which tap you used to fill the sink can have a much bigger effect. Try out a number of sinks in this country and see if you always get the same result!
So what...?
There is an effect called the Coriolis effect which is due to the fact that the earth spins around. On a large scale it can have an effect on weather systems. Hurricanes and tornadoes almost always spin anti-clockwise in the Northern hemisphere and clockwise in the Southern hemisphere.
