# Why does pouring soda slowly and smoothly seem to keep more of the carbonation?

So, I caught myself gently pouring a can of soda into a cup of ice (making sure that there was room for air to move through so the stream of soda from the can to the cup was consistent and even) instead of just haphazardly tilting and dumping the entire thing in there as quickly as possible. I was doing this in part to prevent spills at my desk, but also to keep the carbonation present in the soda. This got me wondering: why does pouring soda quickly cause it to fizz more and lose carbonation?

Because your soda is a supersaturated solution of $\ce{CO}_2$, and such solutions are non-equilibrium and hence unstable. Any physical disturbance (shaking, touching a rough surface, etc.) causes it to emit the gas and return to equilibrium state. Throw in some salt, and you will see a reaction even more vigorous.