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Wonder about atom characteristic

  1. Nov 6, 2009 #1
    First to tell, I'm a ordinary people who curious in science field. I can't use difficult word myself but I can understand when you use it don't worry.


    Most of atom is space right? (Nucleus at center and electron cycle around very far away compare to it's size.)

    Okay, what I wonder is...
    Everything is made up of an atom, dose that mean Most of all matter is space? include human body?
    than why we can't walk through or see through eachother?

    If Everything is made form atom,than what make matter different? I mean, What make meat different than Iron?

    If we strip 'single' atom from meat and iron, what make it different?

    P.S English is not my native language, forgive me if I'm wrong in gramma or spelling
  2. jcsd
  3. Nov 6, 2009 #2
    There are multiple reasons but the primary one would be the electro-magnetic force that keeps electrons from getting too close. Think of each atom as surrounded by electrons and they are all negative charge so they have a repulsive force on each other preventing you from moving one atom through another.

    One other reason is the pauli exclusion principle which says that fermions (leptons/quarks, thats what electrons and protons/neutrons are made of) cannot occupy the same space and be in the same quantum state. Light does not behave in this way, light is made of bosons and due to their nature you can have any amount you want in the same space, they do not interact with each other via the pauli exclusion principle.
  4. Nov 6, 2009 #3


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    Sure, but defining 'space' or 'empty space' isn't an easy thing to do at the level of atoms.
    Atoms aren't tiny hard spheres, they consist of electrons and nuclei. Only the electrons aren't tiny hard spheres either (they're in fact tiny points, as far as we can see). But they don't quite act like little dots whizzing around either - they're 'smeared out' and all we can say for sure at any given moment is the probability of where an electron is.

    The nucleus on the other hand isn't a hard sphere either, it's made of neutrons and protons, which are made up of quarks, which are made up of - we don't really know.

    You can't walk through someone else because the electrons surrounding an atom are negatively charged. If two molecules get close to each other, the electrons will cause them to repel each other.

    You can't see through another person because the molecules we're made out of absorb visual light. On the other hand, they don't absorb many radio waves (for instance), which is physically the same thing as light - just a very 'different color'. If your eyes were sensitive to radio waves instead then you would be able to see through people. (except their eyes I guess, since those would be required to absorb radio waves in order to detect them)

    Well, first elements. Iron is an element. Meat is mostly made out of carbon, nitrogen, oxygen, hydrogen. (Compare: Metals with non-metals, or two different metals)

    Second: Chemical bonding. How molecules are put together in terms of chemical bonds.
    (Compare: Coal to diamond. Both are made out of carbon)

    Third: Structure. How the molecule is put together in its big, overall structure.
    (Compare: A polyethylene plastic bag to some oil. They're made out of more or less the same elements,
    carbon and hydrogen, with the same bonds, but with different molecule lengths and shapes)
  5. Nov 6, 2009 #4
    Electro-magnetic push between two atom is seriously strong huh.

    So, If we smash two atom into eachother with force that strong enough to penetrate electro magnetic push, what become of it? Nuclear fission?

    I think I heard big project about ...cern... or zern... are they try to do same thing?
    Oh I get it, Iron is pure single element but meat is compound of many element.
    If we can divide all of meat atom and arrange it element by element, it will become same.

    Than what about atom of two different element? Single atom of Iron and single atom of cabon, they both also element right? what make it different?
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