a small amount of water in an empty soda can. Place the can on a hot
plate and heat until the water boils. While waiting, prepare a large
container of cool water. Once the water has begun to boil, use tongs to
pick up the can and quickly turn it upside down and place it in the
water bath. The air in the can heats up, the air molecules start moving
faster and some find their way out of the can, creating an area of low
pressure. Turning the can upside down into the water creates a seal in
which no air molecules are able to re-enter the can. The pressure
outside of the can is greater, and the can is crushed.
To see a “real life” example of this phenomena, check out what happened to this train car when it was washed with hot water and sealed before it was cool.