Glass Sphere Rainbow Demo
Glass Sphere Rainbow

 

Code Number: 6A46.16

Demo Title: Rainbow - Glass Beads, Spheres, and CD's

Condition: Good

Principle: Refraction

Area of Study: Optics

Equipment:

Old Filmstrip Slide Projector, Large Poster Board Mask with 4 Inch Hole, Round Bottom Flask, Glass Crystal Ball, Tubular Stand for Balls and Flask.

Procedure:

A rainbow from a drop can be simulated by filling a round flask with water.  Place a large cardboard mask with a hole in the center in the middle of the table.  Place the flask at the same height as the hole and on one side of the mask.  Place the filmstrip projector on the other side of the mask, pointing through the hole and at the flask.  Turn on the projector, and the rainbow should appear on the same side of the mask as the raindrop.  A secondary bow can be seen if you look closely.

The glass crystal ball may be substituted for the flask of water.  You will not see a secondary bow.

References:

  • Yuan Zheng, Kexun Shen, Xianghe Wang, Xing-Xing Yao, "Rainbows in Different Refractive Indices", TPT, Vol. 61, #5, May 2023, p. 351.
  • Markus Selmke, "Ground Rainbows: A Cautionary Tale for Authors and Editors Alike", TPT, Vol. 58, #6, Sept. 2020, p. 372.
  • Dave Van Domelen, "More Ideas for Projecting a Rainbow", TPT, Vol. 55, #3, Mar. 2017, p. 132.
  • Dragia Trifonov Ivanov and Stefan Nikolaev Nikolov, "A New Way to Demonstrate the Rainbow", TPT, Vol. 54, #8, Nov. 2016, p. 460.
  • G. Planinšič, A. Corona, and J. Slisko, "Rainbow-Like Spectra with a CD: An Active-Learning Exercise", TPT, Vol. 46, #6, Sept. 2008, p. 329.
  • P. J. Ouseph, "CD Rainbows", TPT, Vol. 45, #1, Jan. 2007, p. 11.
  • Paul Chagnon, "Optics for People Stuck in Traffic: License Plates", TPT, Vol. 33, #2, Feb. 1995, p. 112.
  • Joseph Frick, "#168 - The Rainbow", Physical Technics: Or, Practical Instructions for Making Experiments in Physics and the Construction of Physical Apparatus with the Most Limited Means", p. 197.