Diffusion Lab

My partners , Jalen , Kaleb, and I completed a diffusion lab. Diffusion is the process by which molecules spread from areas of high concentration to areas of low concentration. The purpose of the lab was to observe the diffusion of a substance across a semi permeable membrane. A plastic Baggie was used as the semi permeable membrane because it has tiny holes that allow certain things to go through. Starch was put in the Baggie and it was tied up and placed in a beaker with water and iodine. The iodine is a indicator for starch. Iodine is a substance that changes the color in the presence of the substance it indicates. In this lab we predicted that if the Baggie was permeable to iodine, then the iodine would diffuse into or through the bottom of the bag and change the color of the starch. We also predicted that if the Baggie was permeable to starch it would move out the bag through the bottom.  Lastly we predicted that the color of the solution in the Baggie would change and the solution in the beaker would sta the same. After the data was collected from the experiment , we found that the Baggie is permeable to iodine. We came to this conclusion because the starch turned purple after coming in contact with the iodine. Our predictions were right. The Baggie isn't permeable to starch because it didn't move because it is too big of a molecule. Since the Baggie allowed the iodine to go through it is selectively permeable. An example of something selectively permeable in the real world would be a strainer because it allows things small enough to fit through the holes to go through. I learned that it is not a good idea to store iodine in a plastic bag because it would leak out and stain everything. Jalen said that he learned what happens during diffusion as well as Kaleb.