Sweet and Salty: The Effect of Particle Size on the Rate of Diffusion Across a Semi-Permeable Membrane

Abstract

Some substances diffuse through a semi-permeable membrane faster than other substances.  We hypothesized that smaller molecules will have a faster rate of diffusion across a semi-permeable membrane than larger molecules because the smaller molecule will more easily fit through the pores of the membrane.  We will be approaching this issue by testing different sized molecules to see how this affects the rate of diffusion. We used dialysis tubing to represent semi-permeable cellular membranes and monitored the rates of diffusion of salt and glucose molecules.  This research will help companies use artificial cell membranes for various useful applications.