Basically title.
My basic physics knowledge says that the larger chips - near the top of a bag of chips - are not “stable”, they are kinda precariously balanced only at one or two points. But once the brittle chips break down, they tend to settle at the bottom because the crumbles are more “stable” there, and are at a lower state of potential energy.
Just my own theory, but would like to know what others think here.
I tend to think about it as density. Smaller chunks can be more tightly packed together, and are therfore more dense. As long as there is a way for the stuff to flow (i.e. shaking the bag), gravity will pull denser stuff to the bottom.