Diffusion and Osmosis Purpose: The purpose of the lab was to observe the processes of diffusion and osmosis occur through selectively permeable membranes. Procedure: First of all, we set up our dialysis tubes, taking one end of the tube and folding it over once and then folding it again. Then, we folded it Diffussion back and forth tying an end off. We then made four of these all together, and marked them, to differentiate them. We then soaked these tubes in water. For the tube labeled “A”, we used a pipette and filled the dialysis tube with 10mL of water. For the other tubes B and C we used 10% sucrose and 25% sucrose solutions. The largest beaker was filled with 2/3 water. We had already noted the initial weights down, after we had soaked the tubes in water we noted down the weight at 15 minutes, 30 minutes, 45 minutes, and 60 minutes. All of this was done while the beaker was heated and was in a state of boiling. We wrote down these weights in a table. The bags that changed colors we knew they had changed in general. Ten we obtained a clean slide to make a wet mount of an Elodea leaf, and we then placed it under the microscope. Another slide was obtained and we made a wet mount of an Elodea leaf, but this time for the wet mount we used NaCl. After a few minutes of viewing both of the slides we got our results of their comparison. Observations: We observed that the Bag with Iodine in them changed colors, but the solution did not change colors. This meant that the Iodine perriated the cell membrane. The bag with the Phenolphthalein also changed colors and so did the solution inside. This meant that the NaOH perriated the cell membrane and the phenolphthalein leaked out. We also observed that the plasmolyzed plants were brown compared to the green regular plant cells and they were more detailed. Conclusion: Diffusion is the movement of molecules from an area of a high concentration to an area of lower concentration. Osmosis is the diffusion of water across a membrane from a high concentration to a low concentration. Plasmolysis is the process in which water exists in a plant cell.