brownian motion

Brownian movement

[brou-nee-uhn]
noun Physics.
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 Robert Brown in 1827.
Also called Brownian motion.


Origin:
1870–75; Brown + -ian

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World English Dictionary
Brownian movement (ˈbraʊnɪən)
 
n
random movement of microscopic particles suspended in a fluid, caused by bombardment of the particles by molecules of the fluid. First observed in 1827, it provided strong evidence in support of the kinetic theory of molecules
 
[C19: named after Robert Brown]

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Etymonline
Word Origin & History

Brownian movement
1871, for Scottish scientist Dr. Robert Brown (1773-1858), who first described it.
Online Etymology Dictionary, © 2010 Douglas Harper
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American Heritage
Medical Dictionary

Brownian movement (brŏu'nē-ən)
n.
The random movement of microscopic particles suspended in a liquid or gas, caused by collisions with molecules of the surrounding medium. Also called Brownian motion, molecular movement, pedesis.

The American Heritage® Stedman's Medical Dictionary
Copyright © 2002, 2001, 1995 by Houghton Mifflin Company. Published by Houghton Mifflin Company.
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American Heritage
Science Dictionary
Brownian motion   (brou'nē-ən)  Pronunciation Key 
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). See also kinetic theory.
The American Heritage® Science Dictionary
Copyright © 2002. Published by Houghton Mifflin. All rights reserved.
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American Heritage
Cultural Dictionary

Brownian motion definition


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.

Note: Brownian motion was first explained by the twentieth-century physicist Albert Einstein, who considered it direct proof of the existence of atoms.
The American Heritage® New Dictionary of Cultural Literacy, Third Edition
Copyright © 2005 by Houghton Mifflin Company.
Published by Houghton Mifflin Company. All rights reserved.
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