Soap-Powered Paper Fish
The fish shoots forward.
Teaching & key ideas
What you do: Float fish and touch soap into the rear notch.
What students see: The fish shoots forward.
Why it works: Soap lowers surface tension behind the fish, creating an imbalance that pulls it forward.
Question to ask: What pushed the fish if nobody touched it?
Lesson flow
Predict → demonstrate → observe → briefly explain → ask: What pushed the fish if nobody touched it?