Preparing semi-permeable membranes.
- Take two raw eggs.
- Keep the two eggs in dil. HCl for 4 to 5 hours.
- The shells which are made of calcium carbonate (CaCO3 ) are dissolved.
- Wash the eggs under tap water.
- Carefully pierce a pencil sized hole in the egg membrane and drain the contents.
- Wash the membrane with fresh water. Now the semi-permeable membrane is ready for use.
Experiment of osmosis with egg membranes :
Aim :
To prove osmosis through semi- permeable membrane of an egg.
Materials required :
Two egg membranes, three beakers, sugar, water, thread, measuring jar, disposable syringe.
Procedure :
1. Take one egg membrane and fill it with 10 ml of saturated sugar solution with a syringe.
2. Tie its mouth with a thread.
3. Measure 100 ml of tap water in a beaker.
4. Keep the egg membrane in fresh water beaker.
5. Leave it for overnight.
6. Take the second egg membrane and fill it with 10 ml of tap water with the syringe.
7. Prepare 100 ml of saturated sugar solution and keep the egg membrane in it.
8. Leave it for overnight.
9. Measure the contents of the egg membranes and beakers.
Observations:
1. Water entered into the egg membrane in which sugar solution is filled. So size of the membrane increased.
2. Water left from the egg membrane in which water is filled. The size of the membrane decreased. Result: Water move across membranes from solutions of one concentration to the other through a process called osmosis.
