REAL LIFE NEWS: WHY BEER DOESN’T WANT TO BE SPILLED
by Hazed
Great discoveries sometimes happen in the pub. So do minor ones. Alban Sauret and his colleagues from Princeton University noticed that when they carried drinks from the bar, the beer rarely sloshed out of the glass, provided it wasn’t full to the brim. The same thing happened with a latte, but not a regular coffee. As all good scientists do, they wondered why the foam made a difference to the spillage – and they set about finding out.
They mixed water with glycerol and surfactants (substances which lower the surface tension of a liquid) and then blew bubbles into the liquid, to create a stable foam. With this mix they were able to control the size of the bubbles and the thickness of the foam which allowed them to investigate which aspects stopped liquid from sloshing.
Their conclusion was that just 0.3cm of foam was enough to dampen much of the sloshing motion. 3cm stopped it almost completely.
Never mind stopping you from spilling your drinks in the pub, this study could have some serious applications as well. “Sloshing results in large pressure forces on the walls of the container that can damage the structure or disturb the motion of the vessel,” says Sauret. Covering fluids with a layer of liquid foam could solve the problem, he says.
