Hydrogen discharge tube experiment


To observe the visible components of the hydrogen spectrum


  • Hydrogen discharge tube
  • Spectroscope


  • One of the main features in Bohr's model of the atom was that when an electron jumps from a higher energy state to a lower one, a photon will be emitted
  • Another feature is that the electrons orbit at fixed radii and through an interpretation of the Balmer equation, when an electron jumps from n = 3-6 to n=2, the emitted photon is visible for Hydrogen.
  • The spectroscope allows us to see the deviation of the spectral lines.

Risk Assessment

  • The hydrogen discharge tube requires the production of a high voltage.
  • As a result, harmful radiation and the potential for voltage arcing may occur.
  • To be safe, stand at least 2m away from the tube when it is turned on.


  1. Turn on the discharge tube.
  2. Using the spectroscope, observe the hydrogen discharge tube.


  • You should have observed the above spectrum.
  • The colours shown from right to left are Red, Cyan, Indigo and Violet.


We were able to observe the visible spectrum of the hydrogen emission spectrum.


More information can be found here and you can watch a tube in action here