• Question: Which chemicals change the colour of flame?

    Asked by JimBob!!! to Eoin on 11 Nov 2014.
    • Photo: Eoin Carley

      Eoin Carley answered on 11 Nov 2014:

      Good question! And the answer is…all of them! The colour of anything that emits light depend on what it is made of. Every different element has it’s own unique set of colours. If you make that element emit light it will have a VERY specific set of colours. So much that we can identify a chemical just by looking at the colours of light we see.

      The most everyday flames are hydrocarbon flames, I believe. Mixtures of carbon, hydrogen, oxygen. They generally have a yellowish appearance because of those elements.

      Maybe you could let your teacher experiment with a bunsen burner (which can use natural gas) and see how the flame changes colour as you add more oxygen.

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