Interesting online CONFCHEM discussion going on right now on the ChemWiki and
greater STEMWiki Hyperlibary project. Come join the discussion.

ChemWiki: The Dynamic Chemistry Hypertext > Under Construction > Demonstrations > Additional Demos > Gas Discharge Tubes

Gas Discharge Tubes

Chemical Concepts Demonstrated

  • Atomic emission spectra
  • Bohr atomic model


  • Veritical tubes filled with the following gases are excited. What colors do they glow


    Gas Color
    1. Hydrodgen Blue-violet
    2. Helium Pink-orange
    3. Neon Red
    4. Argon Violet
    5. Krypton Lavender


    Gas Color
    6. Xenon Blue
    7. Mercury Vapor Blue-violet
    8. Oxygen Blue-violet
    9. Water Vapor Pink


The tubes glow their respective colors when the Tesla coil connects with them.  The video shows the gases in the numerical order presented in the tables above.


The Tesla coil is an energy source.  This energy excites the electrons in the gases to higher energy states.  In order to return to the ground state, electrons release excess energy in the form of light.  The light is differently colored in each tube because of the different wavelengths of light that must be released in each instance.

Different elements emit different wavelengths of light to return to their respective ground states, so the tubes' colors are varied.  These colors can be used to produce atomic emmision spectra of the elements electrically excited.  Using known values of emmision spectra, one can perform a similar discharge test on un unknown gas, gather an emmision spectrum from it, and determine which elements are in the unknown gas.



You must to post a comment.
Last modified
10:28, 2 Oct 2013



(not set)
(not set)

Creative Commons License Unless otherwise noted, content in the UC Davis ChemWiki is licensed under a Creative Commons Attribution-Noncommercial-Share Alike 3.0 United States License. Permissions beyond the scope of this license may be available at Questions and concerns can be directed toward Prof. Delmar Larsen (, Founder and Director. Terms of Use