What makes a bottle of beer overflow when you tap another on top of it?

Question

Like that "Man Law" commercial

Answer 1

The reason why any carbonated drink bubbles when you open it is because the pressure above it is reduced. This principle is responsible for this phenomenon. When the bottle gets hit on top, the pressure above the beer is essentially reduced and the bubbles form.

Think about it like this, if you put a piece of paper on top of a cookie sheet and pull the cookie sheet down fast, you reduce the pressure above it and the paper "sticks" to the sheet.

In the case of the beer, rather than the paper staying with the cookie sheet, a precious drink is wasted.

PS: It has nothing to do with the fermentation or shockwaves.

Answer 2

the shock wave from hitting the top of the bottle travels through the entire bottle then go back up the bottle, these shock waves shake the beer up causing overflow.

Answer 3

The chemical failure of the recipient to prevent such occurrence by storing a thumb on top of their beer.

Answer 4

Carbonation.

Answer 5

the fermentation in the beer... like when you shake a beer how it will explode... same concept