Bouncy Eggs

Day 1

option 1: Bring the following items to the front of the room: a banana peel, a rusty penny, a torn piece of paper.

option 2: Pull up the example picture of chemical vs. physical changes (linked in the resources tab). 

• Ask students the difference between the two types of changes. Record their thinking on an anchor chart for later reference. 
• Inform students that we will be conducting our own chemical and physical changes using eggs. 
• Ask students what could be done with the eggs to be a physical change. (Most will want to crack/break the eggs. This is good!)
• Pose the idea: brainstorm with students what would happen to the eggs when soaked in vinegar overnight. Have students record their hypotheses. 
• Place eggs in clear bowls. Submerge completely in vinegar.

Day 2

• Remove eggs from the vinegar.
• Ask students to revisit their initial hypothesis and compare it to the results. 
• Whole class debriefing discussion. Explain the chemical change as follows:

The shell of an egg (typically a chicken egg) is made up of primarily calcium carbonate. If you soak this egg shell in vinegar (which is about 4% acetic acid), you start a chemical reaction that dissolves the calcium carbonate shell. The acetic acid reacts with the calcium carbonate in the egg shell and releases carbon dioxide gas that you see as bubbles on the shell.

differentiation: Dig deeper into vinegar and its properties. This should assist students in hypothesizing and understanding the chemical change taking place.

extension: Ask students what other materials may undergo a chemical change with vinegar. Conduct investigations to test theories.