Colored flames during a flame test. The chemicals being burnt in the flame test are (from left to right): Sodium, Strontium and Boric Acid. The chemicals have been placed on a pad containing methanol which was then ignited. Sodium and Strontium are simple chemicals, called elements. Boric Acid is made up of the elements Boron, Oxygen and Hydrogen. The spectrum of light produced during combustion is unique for each element. An analysis of the spectrum from an unknown, burning substance can reveal its composition.