Has someone ever clunked their bottle of beer on top of yours, resulting in an explosion of foam? It’s hilarious when you pull that trick on an unsuspecting sap, but it’s tragic when it happens to you. My friend Fathead did that to me once back in 1995, and I never forgave him for it. But why does it happen? Science has the answer!
It is a process with three well-defined phases. First, expansion and compression waves appear. These advance inside the liquid and cause the gas cavities (bubbles) to burst at the bottom of the bottle. Afterwards, small balls of foam are formed because the bubbles break into even smaller ones. Finally, given that they weigh less than the liquid surrounding them, these bubbles move to the surface so rapidly that the final result is similar to an explosion.
“Those clouds of foam are very much like the mushroom cloud caused by a nuclear explosion,” notes Javier Rodríguez, a professor in Universidad Carlos III de Madrid’s Department of Thermal and Fluids Engineering. That’s fantastic. Give that man a Nobel prize right now. Read the whole thing at Science 2.0.