Activity: The Flame Test

Days Needed: 1.5 Days
Grade level: 9 – 12


Students will discover first hand how different elements emit different specific wavelengths of light energy when burned, and that these can be identified when the light is separated with a prism.

Science and Math Standards


  • Content Standard 2
    • Mathematics as Communication
  • Content Standard 4
    • Mathematics as Connections
  • Content Standard 8
    • Geometry from an algebraic perspective


    Content Standard B

    • Abilities necessary to do scientific inquiry
    • Understandings about scientific inquiry
  • Content Standard C
    • Structure of Atoms
    • Interactions of energy and matter
  • Content Standard G
    • Nature of Scientific Knowledge
    • Historical Perspectives


  • Math Students should have had some Pre-Algebra, especially in the areas of manipulation of formulas and pattern recognition.
  • Science Students should have had an introduction to the electromagnetic spectrum, the concept of a spectrum and how atoms emit light energy.


Recalling the characteristics of both atoms and light, the flame test is a great way to physically demonstrate some of the more abstract ideas discussed in the background sections on Atoms and Light Energy and Spectroscopy.


The students will work in lab groups of three to four students to construct meaning on the causes of various light emissions from the following 0.5M chemical solutions: LiCl, NaCl, CuCl, BaCl, CsCl, and CaCl. To prepare for the Flame Test, each 0.5M solution should be placed in a test tube by itself. Each of the six test tubes should then be placed at the various laboratory stations 1 through 6. The students will rotate to each station to test the solution.


  • 7 test tubes
  • test tube rack
  • platinum wire or wood splints
  • laboratory burner
  • goggles
  • apron
  • 0.5M solutions of LiCl, NaCl, CuCl, BaCl, CsCl and CaCl, and 1M of HCl

Hand out the student worksheet. Have the students answer the thought questions at the end of Part I in groups, but on paper. They should be utilized to facilitate a meaningful discussion on light emission. Afterwards, the students should complete the questions in Part II individually. They may be assigned for homework if there is not enough class time.


Formative assessment and observation should be evident throughout the lesson. The worksheet, final questions during closure or a future quiz may serve as summative assessment.


Have students take three minutes to write in their own words why different elements produce flames of different colors when burned. How is this quality useful in astronomy?

Reference URL

Flame Test