This is my friend Traci attempting to do the experiment. It didn't work. What is supposed to happen is that the aluminum can will crush itself without using hands to smash it.
You take a can and immerse it in VERY hot boiling water, scooping up some of the hot water. Then you invert it over a pan of very cold icy water and the air inside the can will shrink causing the can to crush itself. But our two tubs of water weren't hot or cold enough. The first time it failed all the kids rushed outside to bring back handfuls of snow. Our cold water was cold enough. Traci boiled some more water but the experiment really needs to be done right next to a flame because the hot water cooled some in the process from moving from the kitchen to the area where they eat and while she was explaining the process. So we are going to try again. We are not allowed to have an open flame though so maybe we'll have to bring all the kids into the kitchen.
What's amazing is that not one kid was disappointed that the experiment failed. They were all excited that they got to participate and help. They want to do lots more and kept suggesting things we can do with them. Which is our whole goal. To spend time with kids.