Particle

For other uses, see Particle (disambiguation).
Arc welders need to protect themselves from welding sparks, which are heated metal particles that fly off the welding surface.

In the physical sciences, a particle (or corpuscule in older texts) is a small localized object which can be described by several physical or chemical properties, such as volume, density, or mass.[1][2] They vary greatly in size or quantity, from subatomic particles like the electron, to microscopic particles like atoms and molecules, to macroscopic particles like powders and other granular materials. Particles can also be used to create scientific models of even larger objects depending on their density, such as humans moving in a crowd or celestial bodies in motion.

The term particle is rather general in meaning, and is refined as needed by various scientific fields. Anything that is composed of particles may be referred to as being particulate.[3] However, the noun particulate is most frequently used to refer to pollutants in the Earth's atmosphere, which are a suspension of unconnected particles, rather than a connected particle aggregation.

  1. ^ "Particle". AMS Glossary. American Meteorological Society. Retrieved 2015-04-12.
  2. ^ "Particle". Oxford English Dictionary (3rd ed.). Oxford University Press. September 2005.
  3. ^ Lambe, T. W.; Whitman, R. V. (1969). Soil Mechanics. John Wiley & Sons. p. 18. ISBN 978-0-471-51192-2. The word 'particulate' means 'of or pertaining to a system of particles'.