Fiber-Optic Water Stream
Light bends around with the flowing water.
Teaching & key ideas
What you do: Shine light into bottle so it follows a curved water stream.
What students see: Light bends around with the flowing water.
Why it works: Light reflects internally at the water-air boundary when angle is steep enough.
Question to ask: How can light turn a corner?
Lesson flow
Predict → demonstrate → observe → briefly explain → ask: How can light turn a corner?