Describe an experiment to demonstrate osmosis

Here's an experiment to demonstrate osmosis:

Materials:

• A potato tuber
• A sharp knife
• A beaker or Petri dish
• Concentrated salt solution
• Distilled water
• A spatula or spoon

Procedure:

1. Step 1: Cut the potato tuber into two halves. Scoop out a hollow cavity in the centre of each half using a spatula, creating a potato cup. Be careful not to pierce through the skin at the bottom.
2. Step 2: Place one potato cup in a beaker containing distilled water.
3. Step 3: Place the other potato cup in a beaker containing concentrated salt solution.
4. Step 4: Leave both setups undisturbed for about 1-2 hours.

Observation:

• In the potato cup placed in distilled water, you will observe that the water level inside the cavity has increased.
• In the potato cup placed in concentrated salt solution, you will observe that the water level inside the cavity has decreased, and the potato tissue might appear flaccid.

Explanation:

• Osmosis is the net movement of water molecules from a region of higher water concentration (less solute) to a region of lower water concentration (more solute) across a selectively permeable membrane.
• The potato cell membranes act as selectively permeable membranes.
• In distilled water (high water concentration), water moves into the potato cells and the cavity, causing the level to rise.
• In the concentrated salt solution (low water concentration), water moves out of the potato cells and the cavity into the surrounding solution, causing the level to fall and the potato to become flaccid.