7B10.11 - Spectral Lines/Spectroscopy - Flame Salts

Code Number:
7B10.11
Demo Title:
Spectral Lines/Spectroscopy - Flame Salts
Condition:
Excellent
Principle:
Spectra of Various Gases, Spectral Lines of Elements
Area of Study:
Optics, Astronomy

Disclaimer

Equipment:
Watch glass, Methanol, Grill Lighter, Bunsen Burner - Mesh Screen Optional, Platinum Bead Wire, Spectroscopy Chemicals (Chloride Salts of Barium, Boron, Calcium, Lithium, Potassium, Sodium, and Strontium), Handheld Spectroscopes.
Procedure:

See also 7B10.11 in Modern Physics.

The best method is to pour a small amount of the desired salt onto a watch glass and wet with methanol.  Light the methanol with the grill lighter and when the excess methanol has burned off and intense color should be produces that is indicative of the salt used.  View the emission lines with a hand held spectra scope or small grating.

NOTE: Doing the above experiment and viewing with an Ocean Optics spectrometer will give quantitative results.

An alternative of this is to fit the small screens onto the Bunsen burner and then to pour a small amount of the desired chemical directly onto this screen.  Heat the platinum wire in the Bunsen burner flame.  Dip the wire into the desired chemical.  Some of the chemical will be melted onto the wire.  Hold this in the Bunsen burner flame and observe the different colors and intensities for the different chemicals.

References:
  • M. Farooq Wahab, "Estimating the Wavelength of Sodium Emission in Flame -- The Easy Way", TPT, Vol. 47, # 6, Sept. 2009, p. 367.
  • Kenneth Brecher,  "Do Atoms Really "Emit" Absorption Lines?",  TPT, Vol. 29, # 7, p.  454 Oct 1991.
  • Eugene Decker, Alan Cromer, "Flame Spectra", TPT, Vol. 21, # 5, May 1983, p. 324.
  • H. L. Armstrong, "Producing Flame Spectra", TPT, Vol. 10, # 9, Dec. 1972, p. 529.
  • Tik Liem, "Color the Flame", Investigation to Science Inquiry, pp. 157.
  • Charles Vivian, "Test by Fire", Science Experiments & Amusements For Children, p. 82.
  • "Flame Testing Salts", Vernier.com, Fall 2008.
  • "Flame Tests",  Chemistry,  p. 27.
  • John Mocko, "Spectroscopy with Balloons", PIRA News, Vol. 9 No 4.
  • Ron Hipschman, "Iron Sparks", Exploratorium Cookbook III, pp. 176.1 - 176.4.
  • W. Bolton, "Molecular Spectra", Book 2 - Waves and Particles, Physics Experiments and Projects, 1968, p. 45-46.
  • Borislaw Bilash II, “Flame Tests“, A Demo A Day – A Year of Physical Science Demonstrations, p. 116.

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.