even though the coldest temperatures in the Antarctic are colder than the sublimation temperature of dry ice, carbon dioxide does not naturally desublimate out of the atmosphere, because partial pressures. (at what temperature does CO2 desublimation actually happen? is it difficult to separate the dry ice from other frozen air components?)
nevertheless, can the cold of the Antarctic still somehow be harnessed to produce dry ice? first idea is simply to leave a pressurized CO2 canister outside. next idea: pressurized CO2 in a warm environment connected by tube to cold chamber cooled by ambient Antarctic environment. the cold chamber remains pressurized even as the CO2 gas gets consumed by desublimation. maybe a balloon could maintain pressure, though rubber behaves poorly at low temperatures.
however, if one starts with pressurized CO2, dry ice can be produced at room temperature: just decrease the pressure and then its temperature will decrease by the ideal gas law. at some point, the temperature becomes low enough for the phase change to occur. this is how dry ice is commercially produced. can Antarctic cold improve yield?
tangentially, can the production of dry ice by depressurization be demonstrated using CO2 canisters easily commercially available for beverage carbonation or air pistols? maybe you also want a press to create pellets.
how can one produce large crystals of frozen carbon dioxide?
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