Singing Aluminum Rod

1. Singing Aluminum Rod Materials: Long aluminum rod; rosin or damp cloth What you do: Hold at center and rub/slide fingers along rod. What students see: Rod produces a loud eerie tone. Question: Where is the rod moving if we can barely see it? 2. Chladni Sand Patterns Materials: Chladni plate or metal plate on speaker/vibrator; fine sand What you do: Drive plate at selected frequencies. What students see: Sand jumps into geometric lines/patterns. Question: Why does the sand choose certain lines? 3. Hydraulic Syringes Multiply Force Materials: Two different-size needle-free syringes; tubing; water What you do: Connect filled syringes and push small vs large piston. What students see: Motion/force differs depending on piston sizes. Question: Which syringe gives more force and which gives more motion?

Predict → observe three demonstrations → compare what changed → choose independent activity station → cleanup/share. Guiding questions: Question: Where is the rod moving if we can barely see it? Question: Why does the sand choose certain lines? Question: Which syringe gives more force and which gives more motion?