: why when you shake a bag filled with something (like food), the bigger pieces ‘rise’ to the top?

Question

: why when you shake a bag filled with something (like food), the bigger pieces ‘rise’ to the top?

In: Physics

Answer 1

When a bunch of pieces of something are in a bag together, they assume the shape of the bag, with little spaces between them where they’re not touching the bag or each other. When you shake the bag they reconfigure slightly, and since the smaller pieces can more easily fit through the small spaces between everything, they fall to the bottom. So the big pieces don’t rise, the smaller pieces fall.