Diffusion And Osmosis Lab Report

Diffusion and osmosis are directly related by that they are the movement of molecules from a high concentration to a low concentration. The main difference being that osmosis is a special kind of diffusion in which water is the solvent and moves from a high water concentration to a low water concentration through a semipermeable membrane. Diffusion and osmosis is vital to living organisms as it is the process by which useful nutrients and other molecules enter the body cell and waste products, from processes such as respiration, are removed. Part A of our lab was meant to show the process of osmosis using cornstarch and iodine. We placed a plastic bag filled with starch and water into a beaker filled with water and iodine. The starting colour of the solution in the beaker was and an amber yellow and the solution in the plastic bag was a foggy off white colour. After 15 minutes the solution in the beaker seemed to be a lighter colour and the plastic bag solution had turned dark purple. Iodine was used as an indicator of osmosis as iodine oxidized with the corn starch. The beaker solution is hypertonic in relation to the iodine solution but hypotonic in relation to the

This not only shows us that the plastic bag is the selectively permeable membrane but also that the iodine molecules are small enough to pass through the membrane of the plastic bag, however starch and water molecules are too big to pass through. All cells want to be isotonic and that still applies to this experiment. Hypotonic solutions occur when the solution outside has a lower concentration than inside. In attempt to create an isotonic solution the iodine flows into the the starch solution but because the starch can not move out of the plastic bag to equalize the concentration, the bag begins to swell. Most animal cells in hypotonic solutions will often swell, tear or