Tuesday 7 August 2018

visible light - Why is the bottom part of a candle flame blue?


What’s the explanation behind the bottom part of a candle flame being blue? I googled hard in vain. I read this. I don’t understand how it’s explained by the emission of excited molecular radicals in the flame. I read that a radical is a molecule or atom which has one unpaired electron. That made me more confused. I want a more detailed, clearer explanation.




Answer



In a lit candle, when gaseous candle wax reacts with the oxygen in the air, the atoms will be unstably excited. To be stable, the excited electrons will relax to the ground state by emitting photons with energy equal to the energy difference between the 2 states. The photons’ energy doesn’t change much, so the wavelength doesn’t change much. The chemical reactions yield light with this spectrum. That light is blue to humans.


source – @gigacyan


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