The earth spins faster in the middle than it does at the poles, where (in the limit) it doesn’t move at all. If a plane in the northern hemisphere is flying south, the earth’s movement from right to left beneath it will become faster as the plane approaches the equator, and then slower past that point. This means that the plane will have to compensate for what feels like a sideways thrust from the right as it approaches the equator, and then one from the left once past it. This thrust is called the Coriolis force, and is supposedly the cause of water going down plug-holes one way in the northern hemisphere, and the other way in the south. It was recently revealed to me that this article of faith from my geeky childhood is in fact rubbish, and that the Coriolis force is far too small to make a difference to the physics of bathtime. You can change the direction of the vortex with your finger (Sidenote: Just how much science has been done in the bath since Archimedes? A lot I suspect) and I imagine that random eddies created by the shape of the bath and its inhabitant also play a role.

Anyway, this is relevant because I was wondering to what extent Toby’s spinning head (see link below) was influenced by the hemisphere of the drinker and indeed the drink. An UK resident’s head spins one way after a few pints of Special, but perhaps the direction of spin can be altered by judicious application of Fosters. You’d probably need a lot though – insert gnats’ piss jokes here. Perhaps Fosters has so little effect in this country because of the extra effort needed to overcome the natural spin of its citizens. I have only to imagine an Australian in a flying bath of Old Peculiar going south in the northern hemisphere drinking Fosters to become thoroughly confused and in need of a drink myself.