The scattering or random reflection of a sound wave from a surface. The directions of reflected sound is changed so that listeners may have sensation of sound coming from oil directions at equal levels.
The mixing of two substances caused by random molecular motions. Gases diffuse very quickly; liquids diffuse much more slowly, and solids diffuse at very slow, sometimes measurable, rates. Molecular collisions make diffusion slower in liquids and solids.
The net movement of molecules in the direction of lower concentration.