CD Rainbow
Three related teacher demonstrations: CD Rainbow, M&M Color Diffusion, Red-Cabbage Color Magic.
Teaching & key ideas
1. CD Rainbow
Materials: Old CD/DVD; flashlight or sunlight reflected safely
What you do: Tilt CD so reflected light lands on wall/paper.
What students see: A rainbow appears.
Question: Where were the colors hiding?
2. M&M Color Diffusion
Materials: White plate; warm water; M&Ms
What you do: Arrange candies, add shallow water, and wait briefly.
What students see: Colored bands spread without stirring.
Question: Why do the colors move on their own?
3. Red-Cabbage Color Magic
Materials: Red cabbage indicator; vinegar; baking-soda water; clear cups
What you do: Add indicator to the different liquids.
What students see: Purple changes to pink/red or blue/green.
Question: Did we add food coloring?
Lesson flow
Predict → observe three demonstrations → compare what changed → choose independent activity station → cleanup/share.
Guiding questions:
Question: Where were the colors hiding?
Question: Why do the colors move on their own?
Question: Did we add food coloring?