Flame analysis is a qualitative test used to identify the components of a substance or mixture. Flame analysis, also known as atomic emission spectroscopy (AES), is based on the physical and chemical principle that atoms--after being heated by flame--return to their normal energy state via the emission of electromagnetic radiation in the form of photons. The frequencies of the photons (i.e., the frequencies of the light) given off are characteristic for each element.

Flame tests are useful means of determining the composition of substances. In general, an unknown substance to be tested by flame analysis is either sprayed into a flame or placed on a thin wire that is then put into a flame. The colors produced by the flame test are compared to known standards to confirm the presence of individual elements in the sample.

Working together, nineteenth-century Prussian physicist Gustav Kirchhoff and German...