• Question: What makes up flames? (or what actually are they)?

    Asked by r3vilo to Andrew, Daniel, Hayley, Natalia, Peta on 18 Nov 2011.
    • Photo: Daniel Scully

      Daniel Scully answered on 17 Nov 2011:

      When, for example, wood is burning, the heat breaks up the molecules of the wood into smaller molecules. Some of the molecules which come off then burn with oxygen in the air – burning releases energy as heat, which breaks up more molecules to keep the fire going. The gases left over from the burning are also very hot.

      Gases are made up of atoms, which are made up of a nucleus and several electrons which surround it.
      The heat energy in the hot gas excites the electrons. The electrons then calm down by giving off the energy as light – and it’s this light which is the flame we see.

      The colour of the light that the electrons give off depends on which element it belongs to. That’s why candle wood has red flames, and methane has a blue flame.
      The temperature of the fire also affects the colour.

    • Photo: Peta Foster

      Peta Foster answered on 17 Nov 2011:

      Flames are the result of a chemical reaction between something that will burn and oxygen. This reaction gives out a lot of energy and it does this as light and heat which we can see and feel 🙂

    • Photo: Natalia Parzyk

      Natalia Parzyk answered on 18 Nov 2011:

      As Daniel said earlier colours in the flames came from different elements (I remember nice demonstrations at Analytical Chemistry labs:) And you can see some of them on the Nottingham university videos http://www.periodicvideos.com/ if you go to a Ca for example and around 5:41 in the video there it is (or S, (http://www.periodicvideos.com/videos/015.htm )around 4:45, Na.. somewhere and some other also have it somewhere). Worth to have a look.

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