What is the difference between osmosis and dialysis?

1 Answer

Osmosis is the diffusion (i.e. movement) of a solvent (e.g. water) across a semi-permeable membrane. Dialysis is the separation (i.e. movement) of molecules themselves.


Osmosis involves water moving from an area of low solute concentration to an area of high solute concentration across a semi-permeable membrane. Dialysis is different to this, and involves the separation of small molecules from large molecules.

Put more simply, dialysis is the movement of molecules in solute (e.g. glucose) and osmosis is the movement of the solvent (water) itself.

Here is a video which describes how osmosis impacts onion cells placed into tap water and then into a salt water solution.

Hope this helps!