Diffusion Experiment: Osmosis in Sucrose Solutions
We used dialysis tubing to simulate a semi-permeable membrane. Since molecules diffuse from their higher concentration to their lower concentration, water will move across the membrane in response to this concentration. While conducting this lab we were able to observe passive transport through diffusion and osmosis. Introduction
Osmosis is a specialized case of diffusion that involves the passive transport of water. When osmosis occurs water moves through a selectively permeable membrane from a region of its higher concentration to a region of its lower concentration. The membrane selectively allows passage of certain types of molecules while restricting the movement of others.
This experiment is a great way to demonstrate the process of osmosis and to show evidence of osmosis occurring over time. We simulated a semi-permeable membrane by using dialysis tubing, which allows small molecules such as water to pass through, but does not allow larger molecules such sucrose to cross. To see if osmosis will occur when there is an imbalance of concentrations on opposite sides of the membrane, we filled the dialysis tubing with various concentrations of sucrose. Our hypothesis was that with a water concentration gradient across the membrane, osmosis will occur. If water crosses into the tubing, the tubing will can weight over time. If the concentration leaves the bag, the bag will lose weight over time, also indicating that osmosis has occurred. As we went through the experiment the weight of the dialysis tubing changed or increased. We predicted that the weight change will be greater with the steeper concentration gradient. Materials and Procedure
Materials used in this experiment were 6 strips of dialysis tubing, string, cups, distilled water, different concentrations of sucrose solutions.
We measured 15mL of 5 different concentrations (1.0M, 0.8M, 0.6M, 0.4M, and 0.2M) of sucrose...
References: Shier, David, Jackie Butler, and Ricki Lewis. Hole 's Human Anatomy & Physiology. 12th. New York, NY: McGraw Hill, 2010. 93-94. Print.
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