Osmosis vs. Diffusion

Osmosis and diffusion are two processes that involve the transmission of particles from one area to another. Osmosis is actually a specific type of diffusion.

Osmosis is the process that allows a liquid to pass through the cell wall of a living organism. It generally occurs when a solvent (such as water) moves into an area of more concentrated solute, thereby equalizing the concentration of solute on both sides of the cell wall or membrane. Living things depend on osmosis to deliver nutrients to cells and eliminate metabolic waste.

Diffusion is the process by which particles of solids, liquids, or gasses move from areas of higher concentration to areas of lower concentration. It is caused by spontaneous movement of thermal agitation and in dissolved substances. It occurs most quickly in liquids and most slowly in solids.

Osmosis is a type of diffusion that occurs across a semi-permeable membrane. With diffusion, particles generally move from areas of high concentration to an area of low concentration, but with osmosis, it is usually low-concentration water passing into a cell with high concentration of another substance to dilute it.