The crusg=hing can experiment is a demonstrationof the strength of air pressure. The can is filled with a small amount of water, and held over a heat source until the water boils. After a few minutes the can becomes full of water vapour. An airtight stopper is ten put into the can opening and made firm.
Cold water is then poured over the can. The steam inside condenses, producing water vapour at low pressure. The atmospheric pressure outside the can is much greater than the pressure of water vapour inside and the can collapses.
