Class XI Practical: Physiology - Demonstration of Osmosis in Living Cells (Potato Osmoscope)

Objective

To demonstrate the process of osmosis using a potato tuber as a living osmoscope.

Guidelines

1. Potato Preparation: Peel a large potato and scoop out a cavity from one side, creating a cup-like structure. Ensure the base is flat.
2. Setup: Fill the potato cavity with a concentrated sugar solution (e.g., 20% sucrose solution). Insert a pin or needle at the initial level of the solution.
3. Immersion: Place the potato in a beaker containing distilled water, ensuring the water level in the beaker is below the level of the sugar solution in the cavity.
4. Observation: Leave the setup undisturbed for several hours or overnight. Observe the change in the level of the sugar solution in the potato cavity.
5. Control (Optional): Set up a control with distilled water in the potato cavity and distilled water in the beaker.

Expected Outcome

An increase in the level of the sugar solution in the potato cavity, demonstrating the net movement of water from the region of higher water potential (distilled water) to the region of lower water potential (sugar solution) across the semi-permeable potato cells.