Set up and experiment to demonstrate osmosis
Answers
Aim of the Experiment
To demonstrate Osmosis process by Thistle funnel and egg's membrane.
Requirements:-
Beaker, Water, Sugar solution, Egg's membrane, an iron stand.

Demonstration of Osmosis process-(A) Experimental Setup and (B) Control Setup
Procedure for the experiment
A wide mouthed thistle funnel with a narrow long stem was taken. Then an egg's membrane collected from an egg is tied tightly around the wide mouth of the funnel with the help of a thread or rubber band. Now dilute sugar solution is carefully poured into the stem of the funnel to a certain level. The wide mouth of the funnel containing sugar solution is now kept in a beaker with the help of an Iron stand. Now three fourths of the beaker is filled with plain water. A similar control setup also arranged but by taking plain water in the beaker and also plain water in Thistle Funnel. The apparatus are left undisturbed for 10 minutes and we observe the changes in the experimental setup as well as in control setup.
Result
After few hours we find the level of sugar solution increases from its initial level in the experimental setup while there is no change in the level of water in the stem of Thistle Funnel in the control setup. This observation clearly indicates the movement of water molecules occurred from the beaker into Thistle Funnel in the case of experimental setup while in the control setup that there is no movement of water molecules from beaker into Thistle Funnel through egg's membrane because both the solutions are of same concentration.
Precautions:-
The egg's membrane has to be tightly fastened to the mouth of the funnel.The initial level of sugar solution in the thistle funnel should be carefully noted.
Osmosis is a process by which molecules of a solvent tend to pass through a semipermeable membrane from a less concentrated solution into a more concentrated one.
Experiment to demonstrate osmosis:
Requirements:
Petri-dish, water, potato, sugar solution, cork and capillary tube.
Method:
Take a potato tuber, remove its outer covering from one end and cut the same end flat.
Scoop out a cavity from the other end of the tuber running almost up to the bottom.
Fill the cavity with the sugar solution and fit an airtight cork fitted with a capillary tube on the upper end of the cavity (fig. 3).
Place the capillary- fitted potato tuber in the water-filled petri-dish.
Mark the solution level in the tube and watch the experiment for some time.
Observations:
After some time the level of the solution in the tube increases. Mark the level of the solution when it stops to move.
Results:
The level in the capillary tube increases because of the fact that osmotic pressure of the sugar solution is higher than that of the water, and the water moves through the semipermeable membrane of potato from petri-dish into the cavity. So the experiment shows that the phenomenon of osmosis.