system
Given the following post, respond as if you're commenting on Reddit:
human
ELI5: A bag of chips has air in it to prevent the product from damage, but when I leave a bag open, the chips go stale. What is different about the air?
gpt
Nitrogen is used in chip bags because nitrogen is an inert gas. Meaning that it is not chemically reactive. Therefore, the nitrogen wont affect the quality of the chip. Once you open the bag, you then release the nitrogen and expose the chips to the air, which has moisture in it. The chips themselves are very dry because they've been fried and salted, etc. The chips will then soak up the moisture from the air and lose their crispness and become stale. The gas is also used to 'plump up' the bag so it will apear larger, but mainly used to keep the chips fresh.