Bouncing Water Drop on Hydrophobic Surface
Drops bead and may bounce/roll.
Teaching & key ideas
What you do: Drop water from low height onto surface.
What students see: Drops bead and may bounce/roll.
Why it works: Weak adhesion plus strong cohesion keeps drops rounded and mobile.
Question to ask: Why doesn't the water spread out?
Lesson flow
Predict → demonstrate → observe → briefly explain → ask: Why doesn't the water spread out?