# PARTICLE SIZE

Notion introduced for comparings dimensions of solid particles (flecks), liquid particles (droplets), or gaseous particles (bubbles). The particle size of a spherical object can be unambiguously and quantitatively defined by its diameter. However, a typical material object is likely to be irregular in shape and non-spherical. The above quantitative definition of particle size cannot be applied to non-spherical particles. There are several ways of extending the above quantitative definition, so that a definition is obtained that also applies to non-spherical particles. Existing definitions are based on replacing a given particle with an imaginary sphere that has one of the properties identical with the particle. Volume based particle size equals the diameter of the sphere that has same volume as a given particle. Which equals 2*(3*volume(particle)/4/pi) ^(1/3). Weight based particle size equals the diameter of the sphere that has same weight as a given particle. Which equals 2*(3*weight(particle)/4/pi/density(particle)/g)^(1/3). Area based particle size equals the diameter of the sphere that has the same surface area as a given particle. Which equals 2*(area(particle)/4/pi)^(1/2). Hydrodynamic or aerodynamic particle size equals the diameter of the sphere that has the same drag coefficient as a given particle.