• Question: Is fire a solid, a liquid, or a gas? (Always been curious)

    Asked by rattyvlogger to Graham, Luke, Maksim, Ruth on 19 Jun 2014.
    • Photo: anon

      anon answered on 19 Jun 2014:

      ok this is a complete stab in the dark, one of the other engineers might be able to clarify but i think that fire is neither a solid, liquid or gas.
      i would say that it is a physical process and not an actual object.
      For the most part, fire is a mixture of hot gases. Flames are the result of a chemical reaction, primarily between oxygen in the air and a fuel, like wood or paper. Along with some other products, it produces carbon dioxide, light, and heat.

      hope this helps

      thanks

      claire

    • Photo: Graham Wiggins

      Graham Wiggins answered on 19 Jun 2014:

      Hi Rattyvlogger,
      ( long answer alert )

      Fire is chemistry in action !

      It is the “exothermic” ( a reaction that gives off heat ) combination of a fuel ( usually carbon rich ) and oxygen ( maybe from the air, or as a liquid or a mixture )
      That’s fire.
      A flame is the hot part of that reaction,as it happens, and it would be a mixture of what ever fuel you are burning and oxygen. – so some partial combustion + some complete combustin, all mixed up. – the process gives out light as it happens, sometimes as a result of “non-pure fuel” or not enough oxy involved.
      There are many types of fire,
      you could hold a piece of tree/wood in your hand, in air, without it burning – you need a source of ignition to complete the “fire triangle” ( there’s something to research later ) and light the wood.
      Some things burn on contact with air, like the metal lithium. that’s a “hypergolic” reaction – quite voilent, and can be used for rocket motors. – they use liquid oxygen, and a fuel like hydrogen. Sometimes they use a “peroxide” oxidizer instead of liquid oxygen ( if you see a word ending in -oxide, or -ide, or similar, there’s a good bit of ohhhtwo in there)
      Some things burn so violently, they are classed as explosives – like gunpowder. that “burns” very quickly, it does NOT detonate. The oxygen is already in the powder, allong with the “fuel”.
      Some fuels,like Methanol, burn in air with a clear flame, making them extremely dangerous. Methanol is also extiguished with water…. an odd thing to do for a liquid fire, you normally use foam, or “drypowder” for liquid fires.
      Once the fuel + air have combined, you’re left with a gas, an oxide of what ever you burnt. so if you burn carbon, with oxygen, you get carbon dioxide. one “lump” of carbon, two of oxygen.

      Fire is almost “alive” it has the ability to feed itself, it can move, can even replicate ! and “breathe”, so has 4 of the 5 criteria of life….

      So, the answer is neither. Sorry,
      Graham
      PS fire is dangerous, and yet usefull, so please be careful and respect the power of fire to create, or , destroy Life.

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