Some beer bubbles goes down...

It's because they don't want to die a slow and painful death by digesture

Last month we read that Australian scientists and a US information technology firm had solved the mystery of the gas bubbles in Guinness stout, which appear to defy the laws of gravity by travelling downwards in the glass.

The solution lay in the shape of the glass and surface effects on its walls, which create a circulating current when the pint is poured. While bubbles rise rapidly through the middle of the glass, they move slowly down its sides.

The net effect is of upward movement - as dictated by the laws of physics - although the bubbles visible to drinkers through the glass walls are descending.