Why Do Chip Bags Puff Up on Planes?

Ever noticed your snack bag puffing up mid-flight? It’s physics at work! In this video, Museum Educator Emily demonstrates how air pressure causes a chip bag to inflate in a vacuum and how sometimes science experiments take multiple tries—our chip bags weren’t exactly cooperating! Because chip bags have air trapped inside of them, when they are placed in an area with low air pressure, such as a plane or a vacuum, that air pushes out on the walls of the bag with more pressure than the air outside is pushing in. This causes the bag to puff up, and sometimes explode!