Atomic Spectra

When a pure atomic gas such as hydrogen or helium is subjected to a high-voltage electrical discharge, light is produced and the gas glows. When this light is observed through a diffraction grating, a series of bright colored lines is observed. The series of bright lines is called an atomic emission spectrum and is unique to each element. In this activity, a spectroscope will be used to view the “bright line” emission spectra of different elements and determine their wavelengths. A spectroscope contains a diffraction grating that separates light into its component wavelengths.