Leaking Soda Bottles

Most recent answer: 10/09/2014

A sealed plastic water soda bottle was lying in our kitchen for several days and it didn't leak, and the temperature was high for the last few days. However, yesterday it rained and cold winds were blowing which reduced the temperature considerably. This morning when I went into the kitchen I found the soda water bottle leaking. I was searching for an answer when I came across this website and read some interesting and somewhat similar questions, so I thought you might be able to help. Thanks in advance!
- Gurpratap (age 30)

That's a very interesting question. I'll make a guess. Perhaps a colleague or a reader will know the answer or make a better guess.

The solubility of CO2 in water goes down as it gets hotter. So a few days in the heat would cause CO2 to leave the solution and join the gas, raising the CO2 pressure in the bottle even beyond the direct effect of simply heating up the gas. When the room cooled down that extra pressure would not go away right away, since it takes a while for the gas to go back into solution.

Now for the pure guess part. Maybe the seal is a bit leakier when it's cold. Perhaps that's due to reduced flexibility of the plastic, something like what made the rubber o-rings on the Challenger leak in the cold. So perhaps the combination of the extra pressure from the gas that hadn't gone back into solution and the colder, more rigid seal was just enough to cause a leak.

Mike W.

(published on 10/09/2014)

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