Dear Friends, I carried out an experiment of sudden release of oxygen (open nozzle) from an oxygen cylinder used for medical college and hospitals. I found that pressure drops quite rapidly and cylinder surface cools from outside such that water droplets accumulate on its surface. This experiment is carried out in an oxygen factory in Goa India. Now I do want to know what is theoretical relation between pressure and time in such a case. Can anyone show me the steps to arrive at such an equation? Vishwajeet, Goa-India.