Class X Practical: Plant Life - Experiments (Osmosis)

Objective

To demonstrate the process of osmosis using the thistle funnel experiment and the potato osmoscope.

Guidelines

1. Thistle Funnel Experiment

1. Setup: Take a thistle funnel and tie a semi-permeable membrane (e.g., parchment paper, cellophane) tightly across its broad mouth.
2. Solution: Fill the thistle funnel with a concentrated sugar solution (e.g., 20% sucrose solution).
3. Immersion: Invert the thistle funnel and place its narrow tube into a beaker containing distilled water, ensuring the level of sugar solution in the funnel is initially higher than the water level in the beaker.
4. Observation: Mark the initial level of the sugar solution in the stem of the thistle funnel. Observe the change in the level of the sugar solution over several hours.

2. Potato Osmoscope

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.

Expected Outcome

In both experiments, an increase in the level of the sugar solution will be observed, demonstrating the net movement of water from a region of higher water potential (distilled water) to a region of lower water potential (sugar solution) across a semi-permeable membrane, which is the process of osmosis.