Egg Osmosis SolutionEgg mass (g) InitialEgg mass (g) after 24 hrsStudent Observations
Vinegar4585Shell gone; egg seemed swollen and larger
10% Salt water8585No change in egg appearance or size
Kayro Syrup8531Egg was wrinkled and shriveled; much smaller
Distilled Water85105Egg was larger in size; swollen and tight

Students performed an experiment using eggs to observe the effect of osmosis on cells. The egg represented a typical cell. Before beginning the experiment, students soaked the raw eggs overnight in vinegar to remove the shells. What they had in hand, then, was actually a raw, shell-less egg.

Solution concentration can be described in terms of tonicity. Solutions are hypertonic, isotonic, or hypotonic to cells. A hypertonic is one that has a greater concentration of solute outside the cell and therefore a lower concentration. Water will leave the cell and move to the outside environment. This is one reason organisms that live in fresh water cannot survive in salt water, such as the ocean. Water will leave the organism’s cells and eventually the cells will undergo plasmolysis and the organisms will die. An isotonic solution is a balanced solution. That is, the solution concentration is balanced with the solution inside the cell. Finally, when a cell is surrounded by a hypotonic solution, concentration of solute is greater inside the cell, concentration of water greater outside. Water moves into the cell and the cell swells. If enough water enters, the cell can burst.

Procedure: Day 1 – Students found the mass in grams of their shelled eggs, recoding the mass in the data table. The eggs were placed in a beaker and covered with 200 mL vinegar to remove the shells.

Day 2 – The eggs were removed from the vinegar. Visual observations were recorded. The shell-less eggs were wiped dry, massed, and the mass was recorded in the data table. The eggs were placed in a clean beaker and covered with a 10% salt- water solution.

Day 3 – The eggs were removed from the salt water and visual observations were made and recorded. The eggs were wiped dry , massed, and the mass was recorded. The eggs were placed in a clean beaker and covered with sugar (Kayro) syrup.

Day 4 – The eggs were removed from the syrup and visual observations were made and recorded. The eggs were carefully wiped with a damp cloth, massed, and the mass was recorded. The student data was recorded in the data table.
Prior to the start of the experiment, the students hypothesized that both the vinegar and Kayro syrup solutions would be hypertonic to the contents of their eggs. The student data can be seen in the data table above. Does this data confirm their initial hypothesis? Explain.
A)Yes. In both instances, the vinegar solution and Kayro syrup, the egg lost mass.
B)No. The egg in vinegar was an isotonic situation; the egg in syrup was hypertonic as it lost mass.
C)No. The egg in vinegar had an increase in mass therefore vinegar would be hypotonic to the egg's contents.
D)No. The egg in Kayro syrup had a decrease in mass therefore syrup would be hypotonic to the egg's contents.