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Conductive materials question

  1. Feb 8, 2009 #1
    If I touch a variety of materials all at the same low temperature, such as wood, metal, bronze, plastic - the most conductive will clearly feel the coldest (even as they're all at the same temp) because those materials are able to transfer heat and conduct with less thermal or electrical resistance.

    but what about glass? glass isnt conductive at all, in fact high power resistors are made from cermaics - but it feels just as cold as metal

    what gives?
     
  2. jcsd
  3. Feb 8, 2009 #2

    malawi_glenn

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    You are asking about the correlation of heat- vs. electric conduction?
     
  4. Feb 8, 2009 #3
    my understanding was that both conduction of heat, and conduction of electrons are based on the same properties...
     
  5. Feb 8, 2009 #4

    mgb_phys

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    Not really.
    Conduction of heat s by phonons, vibrations of the atoms in a material. Conduction of electricity is based on free electrons.
    Crystals and metals have stiff bonds between atoms which allow the vibrations to conduct heat well, but only metals have the free electrons to conduct electricty.
    The most extreme example of this is diamond, it is the best conductor of heat compared to the worst conductor of electricity.
     
  6. Feb 8, 2009 #5
    awesome. perfect answer.
     
  7. Feb 9, 2009 #6

    malawi_glenn

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    diamond is also the hardest material ;-)
     
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