Brownian motion

[ brou-nee-uhn moh-shuhn ]

noun

, Physics.

1. the irregular motion of small particles suspended in a liquid or a gas, caused by the bombardment of the particles by molecules of the medium: first observed by Scottish botanist Robert Brown in 1827.

Brownian motion

/ brou′nē-ən /

1. The random movement of microscopic particles suspended in a liquid or gas, caused by collisions between these particles and the molecules of the liquid or gas. This movement is named for its identifier, Scottish botanist Robert Brown (1773–1858).
2. See also kinetic theory

Brownian motion

1. The erratic motion, visible through a microscope , of small grains suspended in a fluid . The motion results from collisions between the grains and atoms or molecules in the fluid.

Notes

Brownian motion was first explained by the twentieth-century physicist Albert Einstein , who considered it direct proof of the existence of atoms.

Word History and Origins

Origin of Brownian motion¹

1870–75; Brown + -ian