Diffusion, Dialysis and Osmosis Tutorial
Diffusion - The random movement of molecules from a area of higher concentration to an area of lower concentration (the net movement of molecules down a concentration gradient)
Osmosis - The diffusion of a solvent (water) across a selectively permeable membrane. In this case the water molecules always move from the weaker concentration (watery - hypotonic) to the stronger (hypertonic).
Dialysis - The diffusion of a solute (salt, glucose, etc.) across a selectively permeable membrane. In this case the solute molecules always move from the stronger concentration (hypertonic) to the weaker (hypotonic).