Bottle Balloon in Hot and Cold Water

1. Bottle Balloon in Hot and Cold Water Materials: Bottle; balloon; bowls of warm and cold water 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. Question: What changed if we didn't blow into the balloon? 2. Water Dome on a Penny Materials: Penny; dropper; water What you do: Add drops one at a time to a penny. What students see: Water forms a raised dome before spilling. Question: How can water rise above the edge? 3. Soap Collapses a Water Dome Materials: Water dome on coin; toothpick with dish soap What you do: Touch a tiny amount of soap to the water dome. What students see: The dome flattens and spills quickly. Question: What changed when the soap touched the surface?

Predict → observe three demonstrations → compare what changed → choose independent activity station → cleanup/share. Guiding questions: Question: What changed if we didn't blow into the balloon? Question: How can water rise above the edge? Question: What changed when the soap touched the surface?