CAMBRIDGE, England â British scientist Stephen Hawking has decoded some of the most puzzling mysteries of the universe but he has left one mystery unsolved: How he has managed to survive so long with such a crippling disease.
Brownian movement. n. 1. (General Physics) 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.
Diffusion and passive transport: Molecules are in constant motion, moving around randomly (Brownian movement). One result of this random motion is diffusion, the net movement of molecules from an area where their concentration is high to an area where their concentration is lower.