This bag of chips was brought up to 10,678 ft.

The owner took it out of his bag and saw it had become really pressurized.

• Why do bags of chips expand at high elevations?

→ The chip bags are air tight to prevent them from becoming stale. At the higher altitude the air is thinner,which results in lower air pressure on the outside of the bag. The air inside the bag however maintains the original air pressure, which is higher. That causes the bag to expand until the pressure inside and outside are the same again. The bags volume must increase in order for the pressure inside the bag to match the pressure outside the bag.