Fick's law

Fick's laws of diffusion describe the diffusion process, which is the movement of particles from an area of high concentration to an area of low concentration. Named after the German physician and physiologist Adolf Fick, these laws form the basis of our understanding of diffusion in gases, liquids, and solids.

Fick's First Law

Fick's First Law states that the rate of diffusion of a gas is directly proportional to the concentration gradient. This law can be expressed mathematically as:

J = -D * (dC/dx)

where:

• J is the diffusion flux,
• D is the diffusion coefficient,
• dC/dx is the concentration gradient.

The negative sign indicates that diffusion occurs from regions of high concentration to regions of low concentration.

Fick's Second Law

Fick's Second Law describes how diffusion causes the concentration to change with time. It can be expressed mathematically as:

∂C/∂t = D * ∇²C

where:

• ∂C/∂t is the rate of change of concentration,
• D is the diffusion coefficient,
• ∇²C is the Laplacian of the concentration C.

This law is used to understand a variety of phenomena, from the diffusion of pollutants in the atmosphere to the uptake of drugs in the body.

Applications

Fick's laws have a wide range of applications in various fields such as physics, chemistry, engineering, and medicine. They are used to model systems in material science, neuroscience, and pharmacology, among others.

See Also

• Diffusion
• Adolf Fick
• Concentration gradient
• Diffusion coefficient