Argon Spectrum Tube

Spectrum tubes are glass tubes filled with a gas, usually that of an element or small molecule. Sealed metal electrodes are located at the ends of each tube. When a spectrum tube is placed in a spectrum tube power supply and the power supply is turned on, an electrical discharge is passed through the tube, causing electrons in the gas to be excited. As the electrons relax, they emit light-a characteristic color for each gas. When students view the lighted tube through a spectroscope, they can observe the unique set of spectral lines for each gas. Spectrum tubes should only be used intermittently and are not intended as a continuous source of light.

*It is normal for the iodine spectrum tube to contain small pieces of solid iodine.