why when at high altitudes does water bottles, chip bags, etc. expand to maximum capacity?

Question

I recently visited some national parks in California and in sequoia national park, the water bottles, chip bags, sauce packets were all expanded to the point it looked like they could explode at any moment. Why is this?

In: Physics

Answer 1

The air pressure outside drops the higher up you go which causes the bag to inflate with the about of air pressure inside. Sometimes if there isn’t enough room to expand, the explode.