• Question: can wood melt?

    Asked by 09mawass to Alastair, Hywel, Keith on 24 Jun 2010 in Categories: .
    • Photo: Hywel Vaughan

      Hywel Vaughan answered on 24 Jun 2010:

      Excellent question mawas! No, wood cannot melt. Even in a vacuum, you have the elements of carbon, hydrogen and oxygen present, so it will still burn. It will always burn before you reach the temperature at which it would melt.

      You can however cook wood – this can change its properties quite significantly and actually give softwoods the properties of hardwoods!

    • Photo: Keith Brain

      Keith Brain answered on 24 Jun 2010:

      Not really … wood is a very complex mixture of lots of different molecules, all of which have different melting, boiling and sublimation (going straight from a solid to a gas) points.

      If you heat wood in oxygen, it will burn (wood shavings can spontaneously catch light without much heat). So, what about removing the oxygen? This is start, but wood also contains lots of molecules containing oxygen, so I still think that it can oxidise to carbon – this hypoxic smouldering produces coke (the fuel, not the drink and not the drug!).

      So, before it has chance to melt it will undergo lots of chemical changes (loosing water and some other bits and pieces). At normal pressure, if you heat it up the carbon will eventually sublime (it doesn’t melt – it goes straight from a solid to a gas). So, no liquid, and hence no “melting” at atmospheric pressure.

      More advanced stuff (feel free to ignore):
      – there is a “Phase” plot for carbon at () which suggests that if you increased the pressure to around 1GPa (which is about 1000 times our atmospheric pressure) and then heated it up to around 5000 oC (about the temperature of the earth’s core), you can get liquid carbon.