Dismiss Notice
Join Physics Forums Today!
The friendliest, high quality science and math community on the planet! Everyone who loves science is here!

What happens when an element is heated?

  1. May 16, 2015 #1
    Let's say we have a bar of 100% pure iron.
    We know that on a 'human' level- that which we can see with the naked eye, Iron (Fe) will "grow" when heated.
    But on an atomic level,
    Is this due to exansion of the atomic particles,
    or due to a growth of the atom itself,
    or due to an expansion in the area between the valence shells of the atoms?

    Thanks
     
  2. jcsd
  3. May 16, 2015 #2

    russ_watters

    User Avatar

    Staff: Mentor

    The effect is entirely due to the separation between the atoms increasing.
     
  4. May 16, 2015 #3

    phinds

    User Avatar
    Gold Member
    2016 Award

    It is not expansion/growth, it's the energy level of the atoms. They get so excited that they give off photons, much the same way I do when I see a really pretty girl.
     
  5. May 16, 2015 #4
    Thank you Russ.
    Phinds, perhaps you were joking, but yeah, the size of the metal does expand, just like it contracts when cooled sufficiently. As for your other statement, I think pharmaceuticals are available to help.
     
  6. May 16, 2015 #5

    phinds

    User Avatar
    Gold Member
    2016 Award

    Sorry, yeah, I was joking. I mean we both give off photons when heated but I didn't know about the expansion. Fortunately we have russ and others here to correct my boneheaded statements. Actually, the kind of pharmaceuticals I prefer just make it worse.

    EDIT: I want you to notice that I managed to avoid any jokes about my own expansion under the conditions mentioned.
     
  7. May 16, 2015 #6
    No problem. One thing though, I don't think that the metal would have to be heated to the point of producing photons (ie Red Hot) in order for thermal expansion to occur.
     
  8. May 16, 2015 #7

    phinds

    User Avatar
    Gold Member
    2016 Award

    It doesn't have to be red hot to emit photons, it will do that anyway. If it is hotter than its surroundings, it will emit more than it receives and if it is cooler than its surroundings it will emit fewer than it receives, but it will emit them in any case (well, maybe not in the case of supercooling it to near zero absolute).
     
  9. May 17, 2015 #8
    Much appreciated Phind
     
Know someone interested in this topic? Share this thread via Reddit, Google+, Twitter, or Facebook