Diffusion Lab

Today, we had to do a diffusion lab to observe the diffusion of a substance across a semi permeable membrane. We mixed water and cornstarch in a baggie and submerged it in a beaker filled with water and an iodine solution. Then we waited 15 minutes. We added iodine as an indicator for the starch (a substance that changes color in the presence of the substance it indicates). After 15 minutes, we checked on our cornstarch baggies. The lab didn't go as expected. The iodine mixture didn't really enter the baggie and change the color of the water and corn starch mixture. I think this was because the plastic baggie was made a lot stronger so the iodine solution couldn't enter it.