7B11.85 - Spectral Lines/Spectroscopy - Copper Compounds - "Vanish"

Code Number:
7B11.85
Demo Title:
Spectral Lines/Spectroscopy - Copper Compounds - "Vanish"
Condition:
Excellent
Principle:
Absorption Spectra of Copper compounds
Area of Study:
Optics, Astronomy

Disclaimer

Equipment:
Overhead slit slide, holographic grating, solutions of "Vanish" which contain copper phthalocynanine.
Procedure:

See also 7B11.85 in Modern Physics.

Position the slit slide on the overhead and place the holographic grating in the exit beam.  Place the desired copper compound solution over half of the slit.  In this fashion you will be able to see the regular spectrum and an absorption spectrum.

NOTE: The spectrum will be a molecular absorption (band absorption).

The copper phthalocynanine dye in the "Vanish" should have an absorption band centered around 630 nm, with half-widths of about 20 nm.

An interesting variation is to show the absorption peak using lasers.  In picture # 3 above there are 3 laser pointers.  The top laser pointer has a wavelength of 650 nm, the middle has a wavelength of 633 nm, and the bottom (green) has a wavelength of 532 nm.  When a "Vanish" solution of the proper concentration is placed in the path of the lasers the 633nm (middle or He/Ne wavelength) is absorbed.

References:
  • Carlos Eugenio Tapia Ayuga, Alfredo Luis, "Fluorescence in Cola Drinks and Caramel", TPT, Vol. 52, # 1, Jan. 2014, p. 54.
  • Column Editor's Note, "A Vanishing Act", TPT, Vol. 45, # 3, March 2007, p. 184.
  • Gerard P. Lietz, "A Vanishing Act", TPT, Vol. 44, # 9, Dec. 2006, p. 618.
  • Kenneth Brecher, "Do Atoms Really "Emit" Absorption Lines?", TPT, Vol. 29, # 7, July 1991, p. 454.

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.