Answer
This is a hands-on demonstration. Try this with your friends, and be prepared to explain the physics of the demonstration to them. If you use warm water in the pan, it will still condense the steam in the inverted can and cause it to collapse, though not in as spectacular a fashion.
Episode 239 of the television show Mythbusters, titled "Tanker Crush", crushes cans, 55-gallon drums, and even a railroad tankcar with an air pressure differential.