When you buy a bag of chips or whatever it will stay fresh for a long time but once you open the bag it will only last for a few days. How is this possible?

Question

Like there is air in the bag as well so how come it can last for longer period of time when sealed?

In: Earth Science

Answer 1

It can only absorb as much moisture as the air in the bag has which is little, once oppened it has a basically unlimited amount of moisture to be exposed with.