* Diffusion: This is the movement of molecules from an area of high concentration to an area of low concentration. While a membrane is not strictly necessary for diffusion to occur, it often plays a role in regulating the movement of molecules across cell membranes or other selective barriers. For example, gases like oxygen and carbon dioxide diffuse across the membranes of our lungs.
* Osmosis: This is a specific type of diffusion that involves the movement of water molecules across a semi-permeable membrane, from an area of high water concentration to an area of low water concentration. The membrane is crucial in osmosis because it only allows water molecules to pass through, not other dissolved substances. This difference in permeability creates the concentration gradient that drives the movement of water.
In summary: Both diffusion and osmosis involve movement of molecules across a membrane, but osmosis specifically requires a semi-permeable membrane.
