Diffusion and Osmosis Through Dialysis TubingBy Jasper Lee, Leo Zhao, Oliva Skopas, Alistair Dobson, and Alex Bell11/15/13Purpose: The purpose of this experiment was to demonstrate the principles of diffusion and osmosis, two processes essential to life, using a dialysis tube (a semipermeable membrane) to simulate the cell membrane and observe said processes. Introduction: Diffusion is the movement of molecules from a higher concentration to a lower concentration. Imagine you have a glass of water and you put a drop of food coloring in it. The food coloring molecules would move from the initial site of the drop, which has a high concentration of colorant, to the rest of the water, which has a high concentration of colorant. low concentration. Eventually, the food coloring will diffuse so that the entire glass of water contains the same concentration of it. At this point, the glass of water is in dynamic equilibrium, meaning the average concentration of food coloring in the water is the same. Molecules are always in motion, so there will be times when the food coloring converges at one point and leads to a higher concentration. However, on average the concentration is relatively equal. Osmosis is similar to diffusion in that it is the movement of molecules from a high to a low concentration. However, there are two main differences. The first is that osmosis is exclusively the movement of water: the movement of any other molecule besides it is not considered osmosis. The second is that osmosis is the movement of water across a selectively permeable membrane. A selectively permeable membrane is one that allows the passage of some molecules and blocks others. Whether or not a molecule can pass through the membrane usu...... middle of paper ......velop, decreasing the accuracy of the experiment. While the simulations were generally accurate, there were important limitations that dramatically decreased the similarity between it and cell.Works CitedBrooklyn College. “Fluid mosaic model of the plasma membrane.” Fluid mosaic model of the plasma membrane. Brooklyn College, nd Web. November 16, 2013. National Kidney Foundation. "Dialysis." The National Kidney Foundation: A to Z Health Guide. National Kidney Foundation, n.d. Web. November 16, 2013. .Schmidt, Andrea. "Concentration gradients." Concentration gradients. MIT and Web. November 16. 2013. .