Fiber-Optic Water Stream

Light bends around with the flowing water. Ask students to predict what will happen. Shine light into bottle so it follows a curved water stream. Key idea: Light reflects internally at the water-air boundary when angle is steep enough. Ask: How can light turn a corner? Safety and cleanup: Use LED/flashlight, not laser; tray for water. https://www.youtube.com/watch?v=Z9O5xY3Z1WE