Floating Eggs: The students discovered that as an egg ages, air enters the egg and the air cell becomes larger. They learned to test an egg for freshness they can place it in a bowl of water. The fresh eggs will lie on the bottom of the bowl. Eggs that tilt so that the large end is up are older, and eggs that float are rotten.
Invisible Ink: We dipped a paint brush into lemon juice then drew pictures onto different colored paper. After the paper totally dried we used a hair dryer to heat the paper up revealing the original pictures we drew. The students discovered that lemon juice is an organic substance that oxidizes and turns brown when heated which is why we were able to reveal the hidden pictures.