ITS A LAB! On Osmosis...The magical diffusion of water.

Work sheet to go along with our diffusion and osmosis lab

We recently did a lab to learn more about cell membranes.  It was a diffusion and osmosis lab. Diffusion and Osmosis are pretty important, because water and certain solutes get in and out of a cell through these processes. During diffusion and osmosis molecules move from regions of high concentration to regions of lower concentration. We observed this during our lab. We used dialysis tubing as our permeable membrane. We filled a cup with water and then added iodine, which I have now become familiar with from a recent lab on saccharides. We tied off one end of the tubing and filled the tubing with a solution that contained glucose and starch. We then tied off the other end of the bag and placed it in our cup of water and iodine. We left it to sit over night. And then lather, rinse, repeat.<Just Kidding ha ha. When we came back to our cup the next day we found something interesting. The high concentration of glucose passed through our permeable membrane AKA dialysis tubing, into the lower concentration outside of the tubing. We also found that the bag had expanded. This occurred because of osmosis. The water in the cup had diffused into the bag. Obviously, there was a lot going on and passing through and fro. The iodine also got in on the action, the solution in the bag drastically changed color from its nice translucent state to a midnight black. The iodine had diffused from the cup into the bag. Isn't osmosis and diffusion just magical? :)