The movement of water molecules through a semipermeable membrane from the region of higher water concentration to the region of lesser water concentration is called osmosis.
When two solutions of different concentrations are separated by a semi permeable membrane, the diffusion of solvent will take place from the less concentrated solution into the more concentrated solution., till both the solutions attain equal concentration. The semipermeable membrane are allows only solvent and not the solute to pass through it.
The phenomenon of osmosis can be demonstrated by thistle funnel experiment.
The mouth of a thistle funnel is tied with a goat bladder(it act as a semi permeable membrane). Concentrated sugar solution is filled in the funnel. Its level is marked on its neck. The thistle funnel is now placed in a beaker of water. After sometime, the level of the sugar solution in the thistle funnel rises.
The phenomenon of osmosis can be demonstrated by taking grapes. If grapes are immersed in water, they will swell due to the movement of water into the grapes (endosmosis). If however, grapes are immersed in a strong saturated sugar solution, they will show shrinkage due to loss of water into the sugar solution by exosmosis.