Depends on the size and shape of the particles, see https://www.nature.com/articles/429352a.pdf https://www.nature.com/articles/429352a.pdf for a demonstration

Depends on the size and shape of the particles, see https://www.nature.com/articles/429352a.pdf https://www.nature.com/articles/429352a.pdf for a demonstration of the "reverse brazil nut effect".