Diffusion and osmosis are both processes of particle movement, but they differ in what moves and the presence of a membrane

 Diffusion and osmosis are both processes of particle movement, but they differ in what moves and the presence of a membrane.

 Diffusion is the general movement of particles from an area of high concentration to low concentration, while osmosis is the movement of a solvent (usually water) across a semi-permeable membrane from an area of high solvent concentration to low solvent concentration. 

Diffusion:

Definition: The net movement of particles from a region of higher concentration to a region of lower concentration. 

Mechanism: Driven by the random motion of particles, aiming to equalize concentration throughout a space. 

Examples:

Perfume spreading in a room. 

Sugar dissolving in water. 

Gas exchange in the lungs. 

No membrane required: Diffusion can occur in any medium (solids, liquids, or gases). 

Factors affecting rate: Temperature, concentration gradient, and particle size. 

Osmosis:

Definition: The diffusion of a solvent (usually water) across a semi-permeable membrane from a region of higher solvent concentration to a region of lower solvent concentration. 

Mechanism: Water moves across the membrane to equalize the concentration of solutes (dissolved substances) on both sides. 

Examples:

Water absorption by plant roots. 

Movement of water in and out of cells. 

Semi-permeable membrane required: Osmosis specifically involves movement across a membrane that allows only certain molecules to pass through. 

Factors affecting rate: Concentration gradient, pressure, and the nature of the membrane.