Wax Paper Drop Race
Drops bead and move differently on each surface.
Teaching & key ideas
What you do: Place equal drops on different surfaces and gently tilt.
What students see: Drops bead and move differently on each surface.
Why it works: Attraction between water and the surface changes the contact angle and motion.
Question to ask: Why does water spread on one surface but bead on another?
Lesson flow
Predict → demonstrate → observe → briefly explain → ask: Why does water spread on one surface but bead on another?