Air spectrum tube for classroom demonstrations of spectral lines. Spectrum tubes acquaint students with the spectra of common gases in their pure form, and are also used for demonstrating wavelength. Each gas has its own distinctive set of spectral lines when energized and viewed through a spectroscope. A spectrum tube power supply (not included) is required to energize the tube. Glass tube measures 27 cm long with the capillary portion about 5cm long. An electrode is sealed in each end and attached to a metal end cap with a loop for convenient hookup to wire connections. Includes an activity guide.