Why do ice cubes make a cracking sound when placed in fizzy wine (Prosecco)? When placing ice cubes in a fizzy drink such as Prosecco, ice makes a cracking sound, after which the fizzy bubbles more than usual. What is the physics of this phenomenon?

 A: I think (although I cannot find any source for this that is even remotely reliable): 


*

*the cracking is due to a sudden temperature gradient being exerted on the ice, because compared to the ice, the wine is usually pretty warm. This sudden rise in temperature just on the outside causes the ice to fracture. This is accompanied by a cracking sound which is due to the sudden displacement (release of energy) of different layers of the cube during this fracture. I'm actually pretty sure this is at least part of the reason, because often when you throw in the ice, you can see fractures appearing in the ice at the same moment you hear the sound. 

*the increase in bubbling is due to there being more seed locations for bubble formation. Basically, this is true for most things you would throw in; bubbles tend to form best in places where there is an in-homogeneity of some sort; that's why they often form on particular points on the surface of the glass, and not just "somewhere in the middle" of the fluid. Throwing an ice cube in will drastically increase the possible number of formation sites, because ice cubes are usually pretty rough, microscopically speaking.
