Hi there, Im conducting an experiment in which i am boiling a pot of urine that is covered with a plastic sheet. As the water evaporates from the urine the steam causes the plastic sheet to inflate creating a domed shape. The steam then condenses on the domed plastic sheet and drips down to the edges of the pot, collecting in a separate recepticle. I am wondering for a given amount of water/urine, say 100ml, how much does the amount of air within the pot increase as it evaporates. Thanks for any help. Antony.