Osmosis of a sucrose solution through a semi-permeable dialysis membrane bag is demonstrated.
Discussion:
A sucrose solution containing red-colored methyl red indicator at a pH of 4.5 is added to a semi-permeable dialysis membrane bag. The membrane bag is immersed in a solution of pH 7.0. The solution inside the membrane becomes yellow as the pH is raised due to the flow of pH 7.0 solution into the dialysis membrane. The column also rises as this change occurs.
The pressure exerted by the column forces some of the solution in the dialysis membrane bag out of the bottom of the dialysis bag. The presence of this yellow solution is observed by adding acid to the beaker to change the yellow methyl red to the more intense red color.
Credits:
- Design and Demonstration
- George Gilbert Denison University, Granville, OH 43023
- Video
- Jerrold J. Jacobsen University of Wisconsin - Madison, Madison, WI 53706
- Text
- George Gilbert Denison University, Granville, OH 43023
- Kelly Houston Jetzer University of Wisconsin - Madison, Madison, WI 53706
- David Phillips Wabash College, Crawfordsville, IN 47933