eli5 – why does tapping the top of a pop can make it fizz less? Or is that just a myth I’ve been practicing for 30+ years?

Question

What the title says. Pop means soda btw.

In: 1560

Answer 1

It’s 80% myth based on 20% plausible but irrelevant science, as all good myths usually are.

The premise is that small bubbles clinging to the side serve as nucleation points – nucleation being a process by which dissolved gas is able to emerge from solution and return to a gas, a process hindered by smooth surfaces like the inside of a can.

The issue is that nucleation only has limited bearing on the rapid expansion of gas bubbles that occurs when a can is shaken, moreover, the premise relies on the notion that the bubbles dislodge when tapped, using transparent bottles you can see that only a minority of such bubbles are affected by a couple of taps. Moreover, cans already have plenty of nucleation sites, especially when talking about carbonated alcoholic drinks or sugary drinks.