Ajar Rajbhandary 10/6/14 3rd Hour Egg Osmosis & Diffusion Lab Research question: How do different concentrations of salt solutions affect the mass of an ovum? Background Information Cells have an outer covering called the cell membrane. The cell membrane has little holes that let substances move through it. It selectively permeable meaning polar lipid-soluble molecules pass through and nonpolar molecules do not pass through. Or in simpler words, it acts like a filter and only lets certain substances go in and out of the cell. Cells receive oxygen through diffusion. Diffusion is the movement of a substance from an area of high concentration to an area of low concentration. Osmosis is a type of diffusion. It however is the movement of water …show more content…
You may either buy a naked egg or take a normal egg and place it in vinegar for 1 day until the eggshell has completely dissolved. After the shell has been dissolved, the egg will represent the selectively permeable membrane. Hypothesis According to the theories of hypertonic and hypotonic solutions, we can hypothesize that if the salt concentration increases, the mass of the egg will decrease. Materials 25 Naked (Dissolved Shell) Eggs (Ovum) 5 500mL Beakers Water Salt Weighing Scale (g) Stir Stick Independent Variable: 0 mL salt concentration, 1 mL salt concentration, 2 mL salt concentration, 3 mL salt concentration, 4 mL salt concentration, Dependent Variable: Mass (g) Controlled: temperature, time, amount of water, light, egg Procedure Step #1 Skip this step if you have purchased naked eggs 1. Pour 400mL of vinegar into all five 500mL beakers. 2. Gently place the egg into each of the beakers and let it soak for 24 hours. 3. Wash your hands and clean up material 4. Use your stopwatch to measure 24 hours. 5. After 24 hours, gently take out the eggs and rinse it with tap water and remove any eggshells that are still on the egg. 6. Dry off the eggs with a paper towel. Procedure Step #2 1. Measure the initial mass of all 5 eggs and record your