Plastic soda bottle pressure dependence

Demonstration of how internal pressure stabilizes thin-walled containers.

The easiest way to see the importance of the internal pressure in stabilizing these cans is to take a regular plastic two-liter bottle of soda. It's nice and rigid and feels nice and hard, until you open the top, and then all of a sudden it's so flimsy you can barely hold it. It wants to fall out of your hands when it doesn't have the internal pressure to hold it together. They actually design these cans on supercomputers. So drawing — they're making automobile bodies, they're making Coca-Cola cans, they're making lots of things.