The Penny Experiment
- TONS of old pennies! The older the better!
- 3 Clear Cups per group (plan for 5 or so groups, so 15 clear cups)
- dish soap
- vinegar and/or lemon juice
- Students will break into desk teams of 4.
- Students will find on their tables the supplies listed above.
- Mentors will explain to the students the activity – they will be utilizing the materials in front of them to conduct an experiment on how to clean dirty pennies!
- Students will begin by filling one cup with water and adding 10 pennies.
- Students will fill the second cup with water and a few drops of dish soap and add 10 pennies
- Students will fill the third cup with ½ cup of vinegar, 2 tsps. of salt, and add 20 pennies.
- Ask students which solution they think will work best to clean the pennies!
- Take one dirty penny and dip half of into the vinegar solution, but only half, for 15-20 seconds. What did the students observe? Why do they think this happens?
- After about 5 minutes, remove 10 pennies from the vinegar solution and lay them on a paper towel unrinsed. Wait an additional 5 minutes and remove all pennies from all solutions. Rinse the 10 you’ve just removed from the vinegar solution.
- What do the kids notice about the vinegar solution pennies that were not rinsed in water? They turn greenish blue!
Talking Points: What’s the science behind this activity? The copper in the penny reacts with air and salt and turns the penny green!
Download activity here