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In this optics activity, demonstrate diffraction using a candle or a small bright flashlight bulb and a slide made with two pencils. Learners will observe the diffraction pattern and learn that light has wavelike properties.

Quick Guide

Preparation Time:
Under 5 minutes

Learning Time:
10 to 30 minutes

Estimated Materials Cost:
$5 - $10 per student

Age Range:
Ages 8 - 18

Resource Types:
Activity, Demonstration


Materials List (per student)

  • 2 clean new pencils
  • A piece of transparent tape
  • A candle OR a Mini-Maglite® flashlight (available for under $15 in many hardware stores). Do not substitute other flashlights. OR A flashlight bulb for a Mini-Maglite®, two AA batteries, a battery holder (available from Radio Shack), and two clip leads
  • Pieces of cloth, a feather, plastic diffraction grating, a metal screen, a human hair (optional)


  • Life Sciences
    • Human Senses and Perception
      • Vision
  • Physical Sciences
    • Vibration and Waves
      • Wave Properties
      • Diffraction and Interference
  • The Nature of Science
    • The Scientific Process
      • Conducting Investigations


To use this activity, learners need to:

  • see
  • see color
  • touch

Learning styles supported:

  • Involves hands-on or lab activities


This resource is part of:

Access Rights:

  • Free access



Funding Sources:

  • National Science Foundation
  • California Department of Education
  • NEC Foundation of America