Home > Granular matter

Common examples of such matter are

• Corn flakes
• Dry fertilizer
• Gravel
• Grain
• Thermoplastics (prior to being molded)
• Powders
• Sand

In some sense, granular materials do not constitute a single phase of matter but rather may in bulk exhibit the properties of solids, liquids, and gases, depending on the average energy of the individual grains. When the average energy of the individual grains is low and the grains are fairly stationary relative to each other, the granular material acts like a solid. When the granular matter is driven and energy is fed into the system (such as by shaking) such that the grains are not in constant contact with each other, the granular material is said to fluidize and enter a liquid-like state. If the granular material is driven harder such that contacts between the grains become highly infrequent, the material enters a gaseous state. Correspondingly, one can define a granular temperature equal to the root mean square of grain velocity fluctuations that is analogous to thermodynamic temperature.

Further Reading:

Duran, J., Sands, Powders, and Grains: An Introduction to the Physics of Granular Materials. 2000, Springer-Verlag New York, Inc., New York.