Rice Friction Lift
The bottle can lift with the pencil.
Teaching & key ideas
What you do: Pack rice firmly, push in the pencil, then lift by the pencil.
What students see: The bottle can lift with the pencil.
Why it works: Many grains press against the pencil and each other, producing enough friction.
Question to ask: How can loose rice hold the pencil so tightly?
Lesson flow
Predict → demonstrate → observe → briefly explain → ask: How can loose rice hold the pencil so tightly?