Incandescence

The incandescent metal embers of the spark used to light this Bunsen burner emit light ranging in color from white to orange to yellow to red or to blue. This change correlates with their temperature as they cool in the air. The flame itself is not incandescent, as its blue color comes from the quantized transitions that result from the oxidation of CH radicals.

Incandescence is the emission of electromagnetic radiation (including visible light) from a hot body as a result of its high temperature.^[1] The term derives from the Latin verb incandescere, to glow white.^[2] A common use of incandescence is the incandescent light bulb, now being phased out.

Incandescence is due to thermal radiation. It usually refers specifically to visible light, while thermal radiation refers also to infrared or any other electromagnetic radiation.

^ Dionysius Lardner (1833). Treatise on Heat. Longman, Rees, Orme, Brown, Green & Longman. p. 341. The state in which a heated body, naturally incapable of emitting light, becomes luminous, is called a state of incandescence.
^ John E. Bowman (1856). An Introduction to Practical Chemistry, Including Analysis (Second American ed.). Philadelphia: Blanchard and Lea. p. 283. incandesce 0-1860.

[1] Dionysius Lardner (1833). Treatise on Heat. Longman, Rees, Orme, Brown, Green & Longman. p. 341. The state in which a heated body, naturally incapable of emitting light, becomes luminous, is called a state of incandescence.

[2] John E. Bowman (1856). An Introduction to Practical Chemistry, Including Analysis (Second American ed.). Philadelphia: Blanchard and Lea. p. 283. incandesce 0-1860.

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