11.1
Experiment 11
An Eggsperiment
OUTCOMES
After completing this experiment, the student should be able to:
explain the process of osmosis and give several examples of osmosis from everyday
experiences.
predict what happens to red blood cells placed in hypotonic, hypertonic, and isotonic
solutions.
DISCUSSION
This experiment was intended to be a take-home lab. The author's experience has shown this
experiment to be very intriguing to younger children, as well as adults. In fact, it has been used
as the basis for several science fair projects for children of the author's students. There is so
much to be learned from such a simple experiment for all ages. This is certainly one of the
author's favorite kitchen chemistry experiments.
Osmosis may be defined as the movement of water or other solvents through a semipermeable
membrane into a solution of higher molar solute concentration. The movement of solvent
tends to continue until the solute concentrations on each side of the membrane have been
equalized. A semipermeable membrane is one that allows certain smaller molecules to pass
through, while retaining the larger molecules. It is essentially a submicroscopic filter.
Osmosis occurs in all living organisms and is extremely vital to the balance of fluids in cells and
tissues. There is much more to be said about osmosis and you are encouraged to look into it on
your own. There are three additional terms you will frequently encounter when dealing with
osmosis — a hypotonic solution has a lower solute concentration than inside a membrane; a
hypertonic solution has a higher solute concentration than inside a membrane; an isotonic
solution has a solute concentration equal to that inside a membrane.
PROCEDURE
1. Obtain the following materials: one raw egg, vinegar, corn syrup or honey (a saturated
solution of table sugar is a suitable substitute), and one or two small bowls.
