Abstract: An experimental setup is designed to investigate the osmosis phenomenon quantificationally for the basic physics experiment courses. In the experiment, the linear relationship between the osmotic flow and the concentration difference of solutes across the membrane is obtained, and thus the empirical equation of osmotic flow is confirmed. Furthermore, this paper gives the qualitative interpretation of the osmosis phenomenon from the macroseopical and microcosmic physics and introduces the derivation of the law of van＇ t Hoff by elementary kinetic theory.

Key words: osmosis, osmotic flow, van＇t Hoff＇s law