what makes beer spray

Question

You know how when someone decides to annoy you at a party and taps their beer on top of yours to make it foam? I’d love to know what makes that happen. How can a simple tap from a glass bottle make it spray all over the place?

(Not sure I flailed this right, apologies if wrong)

In: Physics

Answer 1

The can (and beer) contains carbon dioxide. Tapping the can can cause bubbles to form in the beer. The result is more CO2 in the top of the can and more ready to be released by the beer (the bubbles). Open the can, top vents, bubbles released from beer, beer foams.