Code Number: 6D30.46

Demo Title: Thin Film Interference - Alcohol Film

Condition: Good

Principle: Thin Film Interference

Area of Study: Optics

Equipment:

Laser with expanding lens, front surface mirror, isopropyl alcohol, paper towel or cotton swab.

Procedure:

Expand the beam of the laser and reflect it off a front surface mirror onto a screen. Dab or spray some isopropyl alcohol onto the mirror. As the alcohol evaporates, interesting and moving interference patterns are observed.

References:

Arthur Eisenkraft, "Interference Patterns Produced an Evaporating Film", TPT, Vol. 17, # 6, Sept. 1979, p. 392.
Gordon McComb, Lasers, Ray Guns, & Light Cannons - Projects from the Wizard's Workbench, p. 153.

Disclaimer

These demonstrations are provided only for illustrative use by persons affiliated with The University of Iowa and only under the direction of a trained instructor or physicist. The University of Iowa is not responsible for demonstrations performed by those using their own equipment or who choose to use this reference material for their own purpose. The demonstrations included here are within the public domain and can be found in materials contained in libraries, bookstores, and through electronic sources. Performing all or any portion of any of these demonstrations, with or without revisions not depicted here entails inherent risks. These risks include, without limitation, bodily injury (and possibly death), including risks to health that may be temporary or permanent and that may exacerbate a pre-existing medical condition; and property loss or damage. Anyone performing any part of these demonstrations, even with revisions, knowingly and voluntarily assumes all risks associated with them.

Instructional Resources and Lecture Demonstrations

6D30.46 - Thin Film Interference - Alcohol Film

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