Can Crush With Ms Green!

So first we started with a Coke can that looked like this ----------------------------------------------------

Then we used this purple (highly flammable) stuff to light a fire to boil the water that we has in the can sitting the can on a metal stand thingy for it to boil. When you started to hear bubbles and see steam you grabbed the hot can with some tongs, next you get a bowl of cold water (better with ice in) and drop the can with the hot water in the cold water and this happened.

So the cold water made the can crush due to something to do with air presure and made it crush!