2017-10-22 · SCIENCE BEHIND THE CAN CRUSH EXPERIMENT. By heating up our can, we boiled the water inside it. The process of boiling turned the water into the vapor and forced the molecules of air out from the can. When we put the can in the cold water, we suddenly cooled it. That cooling caused the water vapor in the can to condense, creating a partial vacuum. Because of that, the pressure outside of the can became much greater than the pressure inside, and that pressure difference crushed the can.