Fick’s law of diffusion

Fick's law of diffusion describes the net movement of matter from an area of high concentration to an area of low concentration due to the random motion of molecules. This process is quantified by the diffusion coefficient (D), which represents the rate of diffusion.1

The law states that the flow rate (j) of a diffusing substance is proportional to the concentration gradient (dc/dx), with the flow being in the opposite direction of the gradient. Mathematically, this is expressed as:

(j = -D \frac{dc}{dx})

The diffusion coefficient (D) is measured in square meters per second (m²/s) and is influenced by factors such as temperature and pressure. Diffusion is significantly slower in liquids than in gases.2