This is a great starting point activity to introduce osmosis and selectively permeable membranes when learning about the cell and cellular processes. To prepare for this activity, eggs are soaked overnight in vinegar to remove the shell leaving behind a “rubber egg” that is surrounded by a selectively permeable membrane.
Once the eggs are prepared, students measure the starting mass of 2 different eggs. The eggs are placed in 2 separate cups and covered with different liquids – water and corn syrup. On the second day, the students remove their eggs from these liquids and measure their ending masses. Based on the difference in mass, students make an argument to explain how the mass/size of the egg changed.
I print the Test it and Reading section and laminate these for my students to have at their tables as I go through the presentation so they can refer to these, but I can still reuse them from class to class and year to year.
Liquids – vinegar,
Scales or Triple Beam Balances
Student Reflection Sheets – photocopy
This comes from my “Quick and Cl-Ev-R” series. Each activity is designed for students to practice writing scientific arguments with Claim, Evidence, and Reasoning based on real world data and experiences. Each activity includes a quick hands on activity or demonstration, data collection, and corresponding reading focusing on the scientific concepts presented in the activity.