Soap Collapses a Water Dome
The dome flattens and spills quickly.
Teaching & key ideas
What you do: Touch a tiny amount of soap to the water dome.
What students see: The dome flattens and spills quickly.
Why it works: Soap lowers the water's surface tension.
Question to ask: What changed when the soap touched the surface?
Lesson flow
Predict → demonstrate → observe → briefly explain → ask: What changed when the soap touched the surface?