Researchers come closer to solving the "Brazil Nut problem" — coming up with a technical explanation for the tendency of larger nuts in granola and nut assortments to migrate to the top of the jar, even though intuition says that the larger (and hence heavier) pieces would sink to the bottom.
Effectively, the Brazil nut must move through two "fluids" — the smaller pieces of cereal and the tiny air pockets in between them, known as interstitial air, which is background air pressure. Previous attempts to explain the effect had considered only the former.
(via Electrolite)
