6A44.57 - Submerged Light Bulbs

Code Number:
Demo Title:
Submerged Light Bulbs
Lenses and Image Formation
Area of Study:
Frosted light bulbs or radiometers.

Place the frosted bulbs into a tank of water.  The glass envelope will appear to thicken and the frosted coating will appear to shrink as the bulb is submerged.

A glass radiometer can be substituted for the frosted light bulb.

  • James E. Kettler, "Some Optical Effects Using a Hollow Sphere and an Aquarium", TPT, Vol. 22, #3, Mar. 1984, p. 171.
  • Van E. Neie, "Optical Effects in a Neutral Buoyancy Simulator", TPT, Vol. 19, #1, Jan. 1981, p. 53, also A Potpourri of Physics Teaching Ideas - Optics and Waves, p. 211.
  • Richard Breslow, "Optics in a Fish Tank", TPT, Vol. 14, #4, Apr. 1976, p. 234, also A Potpourri of Physics Teaching Ideas - Opics and Waves, p. 209.
  • Mark C. James, "Novel Optical Properties of a Submerged Light Bulb", AJP, Vol. 76, #9, Sept. 2008, p. 856.
  • Doug Johnson, "Future Index of Refraction Demo", Tap-L discussions, Sept. 24, 2008.

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