6C10.20 - Diffraction - Fingers and Squinting

See paragraph one in the procedure section.
Code Number:
Demo Title:
Diffraction - Fingers and Squinting
Diffraction of Waves
Area of Study:
Optics, Astronomy
A distant or pinpoint light source, your fingers.

Look at a distant light source through a gap in your fingers that are just far enough apart to see through.  You should see a diffraction pattern that changes as you increase or decrease your finger gap.

  • Robert Ehrlich, "Q.9, Squinting at an Unfrosted Bulb", Turning the World Inside Out, p. 201.
  • Borislaw Bilash II, David Maiullo, "Two-Finger Diffraction", A Demo a Day: A Year of Physics Demonstrations, p. 350.

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