Diffusion Lab

10/11/11

   Today at school, I did a diffusion lab in science class. In this lab,I observed the diffusion of a substance across a semi permeable membrane. A known indicator for starch is iodine. An indicator is a substance that changes the color of the substance it indicates. We realized that the iodine changed the color of the starch which was now purple. This reaction caused to happen due to the molecules move from areas of high concentration to areas of low concentration. The diffusion (process by which molecules move from an area of higher concentration to a lower concentration) of water molecules through a selectively permeable membrane is osmosis. In conclusion, the iodine's molecules went through the membrane into the baggie's molecules filled with starch and it caused it to turn purple.