Supplies: · Lots of pennies · Water · Dish soap · ½ cup vinegar · 2 tsp. salt · 3 clear plastic cups
Fill one cup half full of water, one cup half full of water and a small squirt of dish soap (stir) and the last cup with ½ cup of vinegar and 2 tsp. of salt (stir). Place 5-10 pennies in the first two cups and 10-20 pennies in the cup with vinegar and salt.
Leave for 5 minutes. Remove half of the pennies from the vinegar and salt mix. After an additional 5 minutes remove all pennies one cup at a time keeping each cup of pennies separated.
Rinse off soap and water pennies. Rinse off second set of vinegar and salt pennies. Compare the differences. If children don’t see any visible differences stick an unclean penny half way into the vinegar and salt mix. Hold it for 15-20 seconds. Observe how half of the penny is cleaner than the other half.