Magdeburg Suction Discs

1. Magdeburg Suction Discs Materials: Two suction cups with handles What you do: Press cups together and invite a controlled pull apart. What students see: They can be very difficult to separate. Question: What is pushing the cups together? 2. Syringe Air Spring Materials: Needle-free syringe with tip sealed What you do: Push the plunger against trapped air and release. What students see: The plunger pushes back and springs outward. Question: Can air act like a spring? 3. Paper Won't Enter the Bottle Materials: Dry plastic bottle; small crumpled paper ball What you do: Place the ball at the mouth and blow straight into the bottle. What students see: The ball often pops back toward you instead of going in. Question: Why can't the paper simply move into the bottle?

Predict → observe three demonstrations → compare what changed → choose independent activity station → cleanup/share. Guiding questions: Question: What is pushing the cups together? Question: Can air act like a spring? Question: Why can't the paper simply move into the bottle?