The Rate Of Diffusion

Introduction Fick’s Law is used to measure the rate of diffusion. Diffusion is the movement of molecules from a region of high concentration to low concentration (Smith, 2012). Diffusion is highly important to almost every living organism. With the aid of diffusion various substances are able to passively move through an organism (Anderson et al., 2012). This process of transporting materials throughout the body can occur without the organism having to expend much energy (Anderson et al., 2012). An example of diffusion would be when a human consumes a glass of water; it will be diffused into the blood stream quite rapidly without our bodies putting in any extra effort. Diffusion plays a big role for mammals in their lungs and the intake

First a Fisher Brand Dialysis cellulose acetate membrane tubing (#21-152-14), 12,000-14,000 MWCO (molecular weight cut off), was pre-soaked in distilled water for 20 minutes prior to use, as the barrier between concentration one and concentration two. A grey plastic collar was inserted into the tubing (with the aid of distilled water). It was very important to insert the collar far enough to ensure the tubing completely covers it. A red rubber septum was then placed into the opening and folding the septum back over the collar created a tight

The ½ concentration however begins to plateau at a faster rate then the full concentration, which takes a much longer period of time to reach its plateau (fig.1). The plateau for both of the different iodine concentration concludes that each system is reaching equilibrium and therefore returning to a homeostatic state. Fick’s Law can be used to better understand the patterns in figure 1. It states that the diffusion rate is equal to the difference in concentration. This means that because the difference in concentration between the two solutions (iodine and soluble starch) used in this experiment were greater when the iodine was at full concentration, the rate of diffusion would also be greater. This occurs as the molecules of the iodine want to go from a place of high concentration to that of low concentration therefore the change in absorbance will be larger as more molecules of are passing through the semi-permeable membrane. We can thus conclude that when the iodine solution is at a higher concentration it will have a higher average absorbance as a greater amount of iodine molecules are needed to pass through the membrane to become saturated and return the system to equilibrium (Fig.