Answer to Question #73169 in Other Physics for Adnan Rafi
Why does fog appear just after opening a bottle of a cold drink?
When you open a bottle of a carbonated drink, the air is released. Whenever pressure drops, temperature also drops. Whenever temperature drops, the amount of moisture that the air can hold also drops. Whenever the amount of moisture that the air can hold drops, droplets of water condense out of the air. That's the "fog" that you see (some of it is from the suddenly cooler air that came out of the bottle, some of it is the warm outside air getting cooled by the air from inside the bottle, and shedding its water).