Why Does Bonking Beer Bottles Trigger a Foam Eruption?

It's the classic party prank: smack your beer bottle on top of someone else's and watch as their bottle wells over with a seemingly endless river of foam. As it turns out, the prank has some interesting physics behind it. Scientific American editor Michael Moyer explains.

Video credits:
Edited by Kathryn Free and Eric R. Olson
Produced by Eric R. Olson