I’m thinking of like when you bottle wine that’s still fermenting, and it explodes. I understand that the fermentation process raises the air pressure inside the bottle. What I *don’t* understand is how? When you pump air into a balloon, the air pressure rises because there are *more* air molecules entering the balloon.
With wine in a bottle, you have a fixed amount of matter at a certain temperature. I don’t understand how fermentation could increase air pressure in a closed system?
In: Physics
How can a grenade explode, when pulling the pin doesn’t increase the amount of matter in the grenade? It’s because the explosive molecules (e.g. TNT) are more energy dense than the gases they become during the explosive chemical reaction.
Fermentation is doing an analogous thing (much less quickly). Biochemical reactions inside bacteria are turning sugars into alcohol and carbon dioxide. This unleashes some of the potential energy which had been confining the CO2 into compact, dense sugar molecules. That *binding energy* is ultimately what allowed the bottle to contain so much matter in the first place; as the sugar degrades, its binding energy converts into *kinetic* energy in the CO2 gas.
Basically, chemical energy stored in the form of sugar is turning into physical energy in the form of gas pressure.
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