ABSTRACT
Diffusion of mass in a medium is a spontaneous process leading to the net movement of a substance from a region of high concentration to its adjacent regions of low concentrations. It takes place in the liquid, gas, and even solid phase. Diffusion results from the random thermal motion of the molecules. A general diffusion-type equation has many applications such as the transport of heat (Fourier’s law), electricity (Ohm’s law), and mass (Fick’s law).
