I have no intention of designing, building or experimenting with this, so no worries about safety. I'm just curious and did a Google search for Physics Forums and this was the first to come up. I was wondering, when pressure decreases so does temperature, right? So, were we to have a pop (soda for you heathens :D ) can, how much pressure would it have to have on the inside so that when the pressure was released, it would cool it down to around 40 degrees? Insta-cool beverages! Assume it's already at room temperature (70 degrees) and normal outside pressure (1atm). I'm not really concerned with feasibility or practicality - just curious about the factuality of what would be required. I did do a search already but the only thread that asked this kind of question was closed.