Osmosis and Diffusion are two types of passive transport, which is the movement of a substance across a permeable barrier without the use of energy. Both processes occur in nature in the movement of atoms and molecules. Osmosis and diffusion also occurs with the body to maintain the equilibrium of substances within cells. This is called the concentration gradient. Substances naturally want to move from an area of high concentration to an area of low concentration. This makes the substance equal across the space.
How are osmosis and diffusion different?
Osmosis is actually a form of diffusion, so it is not surprising that many people become confused by the difference between the two. Both osmosis and diffusion are processes by which molecules and atoms are moved to maintain equilibrium. However, there are some other differences in the two processes. Diffusion is the transportation of any solute or chemical; such as oxygen, salt, carbon dioxide. Osmosis is the transport of water across a permeable membrane. Diffusion can occur in any environment, but osmosis can only take place in aqueous environments such a water or blood. In diffusion the molecules or atoms can move in any direction whereas in osmosis the water molecules can only move in one direction. Diffusion is a quick process that happens rapidly, osmosis is a slower process. Diffusion can happen over any distance and molecules can move along the concentration gradient in small or large spaces. Osmosis only occurs over short distances.
The following video explains some of these differences between the two processes: