Bent Pencil in Water
It looks bent or broken at the surface.
Teaching & key ideas
What you do: Place pencil partly in water and view from the side.
What students see: It looks bent or broken at the surface.
Why it works: Light changes direction when it passes between air and water.
Question to ask: Is the pencil really bent?
Lesson flow
Predict → demonstrate → observe → briefly explain → ask: Is the pencil really bent?