is the random movement
of particles in a fluid due to their collisions with other atoms or molecules.
Brownian motion may be considered a macroscopic (visible) picture of a particle influenced by many microscopic random effects.
Because the movements of atoms and molecules in a liquid and gas is random, over time, larger particles will disperse evenly throughout the medium. If there are two adjacent regions of matter and region A contains twice as many particles as region B, the probability that a particle will leave region A to enter region B is twice as high as the probability a particle will leave region B to enter A.
In diffusion, the movement of particles from a region of higher to lower concentration, can be considered a macroscopic example of Brownian motion.
Example of Brownian motion :
- The motion of pollen grains on still water
- Movement of dust motes in a room (although largely affected by air currents)
- Diffusion of pollutants in air
- Diffusion of calcium through bones
Today, the mathematical models that describe Brownian motion are used in math, economics, engineering, physics, biology, chemistry, and a host of other disciplines.