Demonstrations

Spectral Lines/Spectroscopy - Food Coloring

Code Number :	6F10.51
Disclaimer:	Reprinted by permission of Dick Berg, University of Maryland, for use on this website. The demonstrations contained and referenced herein are listed for the purposes of cataloging and describing physics demonstrations which should be conducted only under the direction of a trained instructional support professional or physicist. These demonstrations are not presented for the purpose of being conducted by persons unconnected to this Facility and/or persons not consulting with or being supervised by the recognized instructional support professional or physicist and his/her staff. The University is responsible only for those demonstrations carried out using its own equipment using established safety and scheduling policies, and bears no responsibility for those choosing to use this source material for their own purposes. All demonstrations described and contained herein are public domain, and can also be found in reference materials in libraries, bookstores, and electronic sources. Further information regarding legal liability in use of demonstrations and labs will be found on the web site Injuries in School/College Laboratories in USA. The University of Iowa Disclaimers: University of Iowa Disclaimer All Rights Reserved..
Condition :	Excellent
Principle :	Spectra of Various Gases, Spectral Lines of Elements
Area of Study :	Optics, Astronomy
Equipment :	Holographic grating, Overhead slit mask, White Light Projector, Glass Cell, Food Coloring, Stirring Rods, Large Beakers (2000 ml).
Procedure :	A band absorption may be produced by putting a water cell into the light path of the overhead projector or white light projector. A couple of drops of food coloring stirred into the cell will produce broad band absorption. Dr. Neff likes to do this in reverse!! He likes to start with food colored water and show the band. He then dilutes the colored water to make the band disappear.

References

"Figuring Physics", TPT, Vol. 43, # 2, Feb. 2005, p. 117.

Kenneth Brecher, "Do Atoms Really 'Emit' Absorption Lines?" TPT, Vol. 29, # 7, p. 454, (Oct 1991).

Don Hruby, "Doing Physics", TPT, Vol. 25, # 6, Sept. 1987, p. 402.

O-285: "Holographic Grating-Antifreeze," DICK and RAE Physics Demo Notebook.

O-740: "Fabrics & Theatrical Filters," DICK and RAE Physics Demo Notebook.

Ron Hipschman, "Color Removal," Exploratorium Cookbook III, pp. 174.1 - 174.3.

2.5: Charles Taylor, The Art and Science of Lecture Demonstration, pp. 70-71.

Mail Questions and Comments to: Dale Stille