Coin-Card-Cup Trick
Three related teacher demonstrations: Coin-Card-Cup Trick, Rattleback Reverses Direction, Gyroscope Won't Fall.
Teaching & key ideas
1. Coin-Card-Cup Trick
Materials: Cup; card; coin
What you do: Set coin on card over cup and flick card sideways.
What students see: Coin drops straight into cup.
Question: Why didn't the coin fly sideways?
2. Rattleback Reverses Direction
Materials: Rattleback/celt toy
What you do: Spin it one way, then the other.
What students see: In one direction it wobbles, stops, and reverses.
Question: Why does it only like one spinning direction?
3. Gyroscope Won't Fall
Materials: Small gyroscope
What you do: Spin it and support it from one end of its axle.
What students see: Instead of falling, it slowly turns sideways.
Question: Why doesn't it just fall down?
Lesson flow
Predict → observe three demonstrations → compare what changed → choose independent activity station → cleanup/share.
Guiding questions:
Question: Why didn't the coin fly sideways?
Question: Why does it only like one spinning direction?
Question: Why doesn't it just fall down?