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Heat Capacity/ Density/ Conductivity

  1. Jan 25, 2009 #1
    Hi guys,

    Just like to check with you:

    How does heat capacity, density and conductivity plays a part in the melting of a certain material.

    I mean, if a material has a lower heat capacity, while other factors are the same, does that mean it will melt faster compared to one with a higher heat capacity when exposed to the same amount of heat intensity?

    Likewise for density and conductivity, how to they play a part in the melting of a certain material?

    Thanks.
     
  2. jcsd
  3. Jan 26, 2009 #2

    Mapes

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    Look into thermal diffusivity, which governs how fast thermal energy propagates. It is connected to the variables you mention above.
     
  4. Jan 26, 2009 #3

    minger

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    Thermal diffusivity is important, but I think the OP wanted to know how the specific components affect the melting.

    The thermal conductivity [tex]k[/tex] governs how fast heat is transferred through conduction.
    [tex] q = kA \frac{dT}{dx}[/tex]
    Density and specific heat governs how the temeprature changes with heat.
    [tex] \Delta T = \frac{Q}{mc}[/tex]
    With mass of course being related to density.
     
  5. Jan 26, 2009 #4

    Mapes

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    No, it doesn't; time doesn't appear independently in that equation. Although copper has a higher thermal conductivity than gold, for example, a temperature rise propagates faster in gold. In the heat equation

    [tex]\frac{\partial T}{\partial t}=\alpha \frac{\partial^2 T}{\partial x^2}[/tex]

    (1-D shown for simplicity), the thermal diffusivity [itex]\alpha[/itex] (units m2 s-1) is an exact function of thermal conductivity, density, and specific heat. I wanted to let Skyeagle find the relationship on her/his own.
     
    Last edited: Jan 26, 2009
  6. Jan 26, 2009 #5

    minger

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    whoops, my mistake. Good catch!
     
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