But we all think we have a trick to solve this problem. If the can was accidentally shaken, we just tap it on the top and all will be fine, right?
Wrong! Tapping the top will make no difference. There is a scientific reason why it does not settle the soda.
When a can of soda is shaken, bubbles form on nucleation sites on the sides of the can.
A nucleation site is little discontinuities in the can that encourage dissolution of gases when equilibrium is disturbed - and a bubble of CO2 will grow there until buoyant forces separate it from the surface, at which point it rises, and another bubble immediately begins to grow on that site.
As was explained, these bubbles form on the sides of the can and tapping the top therefore does not make sense.
If you tap the sides of the can, however, it loosens the bubbles from their nucleation sites and then you can safely and without flinching open your can of soda.
