Granular material asteroids. Some examples of granular materials are snow, nuts, coal, sand, rice, coffee, corn flakes, fertilizer, and bearing balls. Research into granular materials is thus directly applicable and goes back at least to Charles-Augustin de Coulomb, whose law of friction was originally stated for granular materials. Granular materials are commercially important in applications as diverse as pharmaceutical industry, agriculture, and energy production. Powders are a special class of granular material due to their small particle size, which makes them more cohesive and more easily suspended in a gas. The soldier/physicist Brigadier Ralph Alger Bagnold was an early pioneer of the
Granular convection similar density, such as muesli mix. Under experimental conditions, granular convection of variously sized particles has been observed forming convection cells similar to fluid motion. The convection of granular flows is becoming a well-understood phenomenon. It may be counterintuitive to find that the largest and (presumably) heaviest particles rise to the top, but several explanations are possible: The phenomenon is related to Parrondo's paradox in as much as the Brazil nuts move to the top of the mixed nuts against the gravitational gradient when subjected to random shaking. Granular convection has been probed by the use of MRI where convection