To demonstrate the principle of osmosis with the help of a living system.
Potato, beaker with water and strong sugar solution.
Potato tuber is taken and its one end is cut to make it flat. At the other end of the potato, a cylindrical cavity is made. Strong sugar solution is poured into the cavity of the potato. This initial level is marked with the help of a ball pin. This set up is called potato osmoscope or potato osmometer.
This potato osmoscope is placed in a beaker containing colored water.
After a few hours, the sugar solution rises within the osmoscope and gets colored.
The reason for the rise in the sugar solution is osmosis. This movement of water molecules towards the higher concentration solution through a membrane is osmosis. The potato cell membrane acts as the semi-permeable membrane.