Guiding Light

Source Institutions

Source Institutions

Add to list Go to activity
Activity link broken? See if it's at the internet archive
In this optics activity, learners use glass and water to demonstrate total internal reflection (TIR). Learners will discover that during this phenomenon light is completely reflected inside the material it's traveling through and not refracted. This resource includes an explanation of this phenomenon and how TIR works in fiber optics as well as links to articles about the reflection and refraction of light.

Quick Guide

Preparation Time:
Under 5 minutes

Learning Time:
Under 5 minutes

Estimated Materials Cost:
free per student

Age Range:
Ages 8 - 14

Resource Type:


Materials List (per student)

  • A rectangular clear glass baking dish
  • A flashlight
  • A clear glass measuring cup
  • A bowl of water


  • Engineering and Technology
    • Engineering
      • Electrical Engineering
    • Technology
      • Information and Communication
  • Life Sciences
    • Human Senses and Perception
      • Vision
  • Physical Sciences
    • Vibration and Waves
      • Light and Optics
    • Light and Optics
      • Lenses and Mirrors
      • Reflection and Refraction
  • The Nature of Science
    • The Scientific Process
      • Conducting Investigations

Informal Categories

  • Electronics


To use this activity, learners need to:

  • see
  • touch

Learning styles supported:

  • Involves hands-on or lab activities


Components that are part of this resource:

This resource is part of:

Access Rights:

  • Free access


  • Cobb, Vicki ; Cobb, Josh


  • All rights reserved, Optical Society of America, 2008