Hi all, I recently encountered this scenario. I placed a (1 litre) glass bottle with water (about half filled) that is corked up near my stove. My wife was cooking and the cork suddenly popped. We discussed this over dinner and I said that it was due the air in the bottle that has become heated and expanded. My wife said it is due to some water turning into water vapour and cause the build up in pressure. I thought that make sense but I am interested to know what really happens in that scenario. Is it mainly due to air expansion or water turning into water vapour that has caused the popping of the cork? I vaguely remember what I learnt in college about the bombardment of molecules but many years has passed and much has been forgotten. Please help us solve this so the debate over dinner table can end. :) Thanks.