|MadSci Network: Physics|
Greetings, Jim: Part of the explanation has to do with the temperature of the water. Another part has to do with the fact that soda pop contains quite a bit of dissolved carbon dioxide. And the last part is the fact that cold water can contain more dissolved gas than can warm water. So, when the ice first melted, it was still quite cold, and so also was the temperature of the canned soda, complete with dissolved carbon dioxide. There was ONLY liquid in the cans, and no carbon dioxide in the gaseous state. Overnight, however, the melted ice warmed up most of the way to room temperature, and so of course also did the canned soda warm up.... Well, since warmer water is able to hold less dissolved gas than colder water,
some of the carbon dioxide began to UNdissolve, and form small pockets of actual gas. And since gases are lighter than water, the cans reoriented, with the trapped gas rising as much as it could. For proof, start with one cold soda can and one warm soda can. Make sure they have both been unshaken for a fair amount of time, and open them gently. When you first break the seal on the warm can, you will hear an extended hiss as the escapes. But when you open the cold can, the hiss will be rather muted, in comparison. Most of the gas in that can is still dissolved in the liquid!
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