Bottle Balloon in Hot and Cold Water
Balloon inflates in warm water and shrinks in cold.
Teaching & key ideas
What you do: Fit balloon over bottle; move bottle between warm and cold water.
What students see: Balloon inflates in warm water and shrinks in cold.
Why it works: Warm air expands and cool air contracts.
Question to ask: What changed if we didn't blow into the balloon?
Lesson flow
Predict → demonstrate → observe → briefly explain → ask: What changed if we didn't blow into the balloon?