Brownian motion

https://doi.org/10.1351/goldbook.B00748
The movement of particles in a @C01172@ system such as an @A00176@ caused by collision with the molecules in the fluid in which the particles are imbedded.
Source:
PAC, 1990, 62, 2167. (Glossary of atmospheric chemistry terms (Recommendations 1990)) on page 2177 [Terms] [Paper]