The children learned about implosions during Chuck Delpier’s (Mr. D’s) workshop. Lowering the pressure inside a can by heating it up creates a situation in which the pressure of the atmosphere crushes the can. This happens because the small amount of water that is placed inside the can becomes water vapour when it is heated up and displaces the air inside the can. Then when the can is quickly cooled, the water vapour returns to a liquid state and since the air pressure outside of the can is greater than that on the outside, the can is quickly crushed. It’s also great fun.