Oobleck: Solid or Liquid?

1. Oobleck: Solid or Liquid? Materials: Cornstarch; water; bowl/tray What you do: Tap quickly, then slowly let fingers/object sink. What students see: It feels solid under quick force but flows slowly. Question: Why does moving faster make it feel harder? 2. Instant Snow Polymer Materials: Instant snow powder; water; clear cup What you do: Add water to a small amount of polymer powder. What students see: Powder rapidly expands into fluffy 'snow.' Question: Where did all the extra volume come from? 3. Balloon Skewer Trick Materials: Balloon; bamboo skewer; small oil/soap; goggles What you do: Push skewer slowly through thick areas near knot and opposite end. What students see: Skewer passes through without popping the balloon. Question: Why doesn't it pop there?

Predict → observe three demonstrations → compare what changed → choose independent activity station → cleanup/share. Guiding questions: Question: Why does moving faster make it feel harder? Question: Where did all the extra volume come from? Question: Why doesn't it pop there?