Iodine-Starch Color Switch
Mixture turns deep blue-black.
Teaching & key ideas
What you do: Add iodine to starch solution.
What students see: Mixture turns deep blue-black.
Why it works: Iodine forms a colored complex with starch helices.
Question to ask: Did we make a new dye or a new interaction?
Lesson flow
Predict → demonstrate → observe → briefly explain → ask: Did we make a new dye or a new interaction?