Luiz Pereira led a team of researchers in Germany, Britain, and France who examined how roasted, shelled peanuts fared in a lager-style beer,
Because the peanuts are denser than the beer, they first sink down to the bottom of the glass.Then each peanut becomes what is called a "nucleation site". Hundreds of tiny bubbles of carbon dioxide form on their surface, acting as buoys to drag them upwards."The bubbles prefer to form on the peanuts rather than on the glass walls," explained Pereira, a researcher at Germany's Ludwig Maximilian University of Munich.When the bubbles reach the surface, they burst.The peanuts then dive down before being propelled up again by freshly formed bubbles, in a dance that continues until the carbon dioxide runs out—or someone interrupts by drinking the beer.
Pereira says the research will continue as the scientists "play with the characteristics of different peanuts and different beers." Great work if you can get it!
See "Scientists explain why peanuts 'dance' when dropped in beer" for more on the science behind dancing peanuts.