Diffusion

DiffusionDiffusion is the spreading out of molecules from a region of high concentration to a region of low concentration. It takes place along a concentration gradiant. Diffusion is a passive process. A feature of diffusion is that is involved the mixing or mass transport without requiring bulk flow.

History of Diffusion Fick's LawFick's laws states that the diffusion flux is proportional to the negative gradient of concentrations. It goes from regions of higher concentration to regions of lower concentration. Brownian Motion From the atomistic point of view, diffusion is considered as a result of the random walk of the diffusing particles. The moving molecules are self-propelled by thermal energy. Robert Brown discovered the random walk of small particles in suspension in a fluid in 1827. Albert Einstein developed the theory of the Brownian Motion.

Examples of Diffusion Everyday examples of diffusion include the way the smell of perfume, bread baking of the unpleasant effects of a stink bomd can spread through a house. If sugar is placed in hot tea it initially stays at the bottom. However, in time, the sugar will spead throughout the tea by diffusion. In biology, Carbon Dioxide diffuses through a lead, Oxygen diffuses out of a lead. Oxygen diffuses from the blood into a cell, and Carbon Dioxide diffuses out of a cell.

Methods of Diffusion Simple passive diffusion occurs when small molecules pass through the lipid bilayer of a cell membrane. Facilitated diffusion depends on carrier proteins imbedded in the membrane to allow specific substances to pass through, that might not be able to diffuse through the cell membrane.

Diffusion