• Question: How does an immense amount of heat create light?

    Asked by Zobo64 to Colin, John, Kevin, Shikha, Triona on 12 Nov 2014.
    • Photo: Kevin Motherway

      Kevin Motherway answered on 12 Nov 2014:

      Great question Zobo, but they’re both part of the same spectrum. An object that contains a large amount of heat energy (or more correctly its molecules are really excited and at a high energy state) will emit radiation in both the thermal and of the electromagnetic spectrum but also the visible light spectrum. The filament in an incandescent light bulb glows white hot as it resists the electrical current flowing through it and emits 90% of the electricity as heat and only 10% as light! If you switched the lightbulb off and look at it with infra-red camera it would still be glowing until it cools down. So a hot object radiates heat in the thermal spectrum, but also in the visible light spectrum if it has a huge amount of heat energy, just like the Sun bathes us in light, thermal heat and UV etc

    • Photo: Shikha Sharma

      Shikha Sharma answered on 15 Nov 2014:

      Hi Zobo64,
      Heat is the amount of energy a single atom has, and this energy causes the electrons in an atom to change energy levels. The light is produced when an “excited” electron has gained enough energy to raise to a higher level via heat, and then falls back to a lower energy level, releasing the energy as light. The higher the amount of energy put into an atom via heat, the more intense the light will be due to a higher release of energy.

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