Ice Fishing with Salt and String

1. Ice Fishing with Salt and String Materials: Ice cube; cotton string; salt; cup What you do: Lay wet string on ice, sprinkle salt, wait ~30 sec, lift. What students see: String picks up the ice cube. Question: How did the string get 'stuck' to ice? 2. Newton's Cradle Materials: Newton's cradle What you do: Release one ball, then two. What students see: Balls on the far side move while the middle balls barely do. Question: How did the last ball know to move? 3. Salt Lifts an Ice Cube on String Materials: Ice cube; cotton string; salt What you do: Lay string on ice, sprinkle salt, wait, then lift. What students see: String freezes onto the ice. Question: Why did salt help the string stick?

Predict → observe three demonstrations → compare what changed → choose independent activity station → cleanup/share. Guiding questions: Question: How did the string get 'stuck' to ice? Question: How did the last ball know to move? Question: Why did salt help the string stick?