10/11/11-Lab Results

Today we were instructed to conduct our second lab. This lab involved the chemical reaction of starch and iodine when separated by a semi-permeable membrane. At the beginning of the experiment, the starch and water solution, in a plastic bag, was white while the iodine, in the beaker, was orange. The sealed bag, now having been in the beaker for about seven minutes, was beginning to be penetrated by the iodine. The starch and the water then separated, the water becoming clear and the starch solution turning purple. The experiment showed that the bag was a selectively-permeable membrane, that allowed the iodine molecules to penetrate into the bag while keeping the starch inside.