Bubble Inside a Bubble
A bubble can exist inside another bubble.
Teaching & key ideas
What you do: Blow one bubble on tray, then carefully blow a second inside it.
What students see: A bubble can exist inside another bubble.
Why it works: Soap films are flexible membranes whose pressure depends on curvature.
Question to ask: Why don't the two bubbles instantly merge?
Lesson flow
Predict → demonstrate → observe → briefly explain → ask: Why don't the two bubbles instantly merge?