Atom

Discussion in 'Physics' started by Lightfire, Nov 29, 2012.

  1. Lightfire

    Thread Starter Well-Known Member

    Oct 5, 2010
    690
    21
    If every matter is made of an atom, then why can't we see atom?

    For example, a gold. You can see gold with your naked eye, right? Gold is also a matter, so it is composed of atom? So we see atom? Where is atom exactly in the gold?:confused:
     
  2. DenzilPenberthy

    New Member

    May 28, 2012
    20
    7
    Err, because they are too small to see with the naked eye.
     
  3. WBahn

    Moderator

    Mar 31, 2012
    17,748
    4,796
    The gold, like all matter (outside of certain things like black holes and such), is almost entirely empty space. What we "see" is the result of interactions between light and the fields around and between the atoms in the gold. It's the same with your butt and the chair you are sitting on. No atom in your butt is actually touching any atom in the chair. But the fields interact and the resulting forces keep the atoms in your butt form simply slipping between the atoms in the chair (and the floor, and the ground, and everything else separating you from the center of the Earth).
     
    abhaymv and Lightfire like this.
  4. DenzilPenberthy

    New Member

    May 28, 2012
    20
    7
    Also, an atom is much smaller than the wavelength of visible light so it would be impossible to 'see' individual atoms with visible light. They can be imaged with an atomic force microscope though.
     
    abhaymv and Lightfire like this.
  5. Lightfire

    Thread Starter Well-Known Member

    Oct 5, 2010
    690
    21
    Hello,

    Thank you Wbahn. You gave me insight over this. What do you mean by "empty space". And how did you relate the bold text to the italicized one?

    What do you call to the fields around and between the atoms in the gold?

    Thanks a lot and please keep things as much as possible in layman's term. I can't understand some scientific wordings.
     
  6. Wendy

    Moderator

    Mar 24, 2008
    20,766
    2,536
    Actually photographs of individual atoms have been taken, using a laser at resonance with with atom. Don't expect to see much, just a bright dot in empty space, but color is critical.

    http://books.google.com/books?id=q37Ytybbp1sC&pg=PA97&lpg=PA97&dq=barium+atom+photograph&source=bl&ots=4rkCqARjTf&sig=_z9K1CdUHuTpL9i6cMIZzJlcdEU&hl=en&sa=X&ei=f2K3UKi4EqrI2AWAnIDoAg&ved=0CFgQ6AEwBjgK#v=onepage&q=barium%20atom%20photograph&f=false

    I'm having trouble finding the actual picture, it is very unimpressive. Remember, what you are really seeing is the outermost electron being excited.

    Then there are the atomic matrix pictures done with (don't remember the name of the equipment) a specialized probe that goes down to the point of one atom. QED? They are used in text books to show the impurities in semiconductor grade silicon.
     
    Last edited: Nov 29, 2012
    Lightfire likes this.
  7. DenzilPenberthy

    New Member

    May 28, 2012
    20
    7
    ...Atomic Force Microscope.
     
    Lightfire likes this.
  8. Lightfire

    Thread Starter Well-Known Member

    Oct 5, 2010
    690
    21
    Thanks. But my question is where the atom really is in gold?
     
  9. WBahn

    Moderator

    Mar 31, 2012
    17,748
    4,796
    What is the mass density of gold?

    What is the mass of a single gold atom?

    How bit is the nucleas of a gold atom?

    How many gold atoms are in a cubic centimeter of gold?

    How much volume, on average, is "taken up" by a single gold atom?

    What fraction of that volume is taken up by the actual gold nuclei?

    The electrons, which are ultra tiny compared to the nucleus, are "swimming" in the void between the nuclei. Most stay relatively close to the nuclei they are bound to, but the outer shell (or two) of electrons interact with multiple nuclei depending on the particular nature of the bonds in that substance.
     
  10. Lightfire

    Thread Starter Well-Known Member

    Oct 5, 2010
    690
    21
    How far is atom to each other? So why gold is colored gold? Does that mean the atom is gold?

    Why can't we see individual atoms though they are packed very closely to each other?

    Why atom cannot be break down? For example, we have 1 atom and we have a very special scissor, would the atom be cutted or not? Is there are force that keep it not cut/divided?

    Sorry, Google sometimes shows results i cant understand.
     
  11. takao21203

    Distinguished Member

    Apr 28, 2012
    3,577
    463
    this is related to the crystal matrix, not so much the atoms.
     
    Lightfire likes this.
  12. Lightfire

    Thread Starter Well-Known Member

    Oct 5, 2010
    690
    21
    Please throw different ideas, if you want. Keep this thread alive
     
  13. MvGulik

    Member

    Nov 3, 2011
    40
    9
    Depends on the number of protons/electrons in a particular atom type.
    More electrons per atom makes them bigger (more electron shells), as atom interactions are generally only skin deep (outer shells)

    ?
    Due to the the different absorption/reflection/etc behavior per atom type for different colors (cq: light, or electromagnetic radiation).
    Gold mainly absorbs most visible light frequencies, except for some frequencies that (combined) are perceive as yellow. And as gold is also a metal its also perceived as highly reflective (mirror wise, if smoothly and polished)
    (And because we classified the color we perceive from gold also as a specific color specification.)

    ?
    When its a gold atom, or: its a atom that has 79 as atomic number (number of protons/electrons)

    ?
    Human scale: there just to tiny so be seen by our eye's
    Atom scale: ... (lacking specific knowledge here to give a general answer)


    Atom's can, and do, brake down. see Nuclear_fission

    See weak nuclear force
     
    Last edited: Nov 30, 2012
    Lightfire likes this.
  14. MvGulik

    Member

    Nov 3, 2011
    40
    9
    ?
    Its your tread. Although splitting your atom question in more specific questions(topic's) would probably be better. Although that of course depends on what your target is for this topic. (A general random atom talk topic don't seems that useful in the long run to me.)
     
    Lightfire likes this.
  15. takao21203

    Distinguished Member

    Apr 28, 2012
    3,577
    463
    Gold has a specific color because the way the atoms are packed in the metal matrix. The atoms are all the same.

    You can not mechanically cut individual atoms. With a very fine blade, you can shear off small clusters of atoms. However shearing off individual atoms is not practically possible.

    Gold is inert however over a long time, it will oxydize, like all metals do. The Surface will actually be covered with oxid forms, sulphide forms, etc., whatever other element is possible to react with gold.

    Also there is no such thing as pure gold there are always impurities. If you could shave off only one atom, and by chance hit a gold atom, then of course it would be pure.
     
    Lightfire likes this.
  16. takao21203

    Distinguished Member

    Apr 28, 2012
    3,577
    463
    He does not properly understand about atoms. You also seem to lack a bit understanding of the difference between atoms and molecular matrix.

    If chemical reactions are involved, people usually talk about ions, not individual atoms are considered.
     
    Lightfire likes this.
  17. Lightfire

    Thread Starter Well-Known Member

    Oct 5, 2010
    690
    21
    Hmmm, I mean different.

    Think of a glitter, a one glitter. Can you see a glitter in a far distance (say about 10 meters away)? But if they are packed together and they are many we can see that right?

    Why in a 10x10x10 meter gold, can't we see atom? Unless there is only 10 atoms there, I can not understand it. In a 10m^3 gold,there are many atoms held together right?

    Sorry for my bad understanding of atom .
     
  18. bertus

    Administrator

    Apr 5, 2008
    15,648
    2,347
    Hello,

    A gold atom is VERY tiny.
    It can not be made visible to the naked eye.
    Read this page of the wiki:
    http://en.wikipedia.org/wiki/Atom

    Halfway down the page there is this image of gold taken with a scanning tunneling microscope:

    [​IMG]

    More information on gold itself can be found on this page of the wiki:
    http://en.wikipedia.org/wiki/Gold

    Bertus
     
  19. takao21203

    Distinguished Member

    Apr 28, 2012
    3,577
    463
    This is because the eye is not a 1:1 WYSIWYG device.
    Only 10% of what you see comes from your eyes. The rest is generated in your brain.

    This mask is made from gold too.
     
  20. WBahn

    Moderator

    Mar 31, 2012
    17,748
    4,796
    If you take the time to answer the questions I asked, you will see that atoms are not packed closely to each other. Atoms can, and do, break down. It is called nuclear fission. Sometimes it happens spontaneously and we call it radioactivity and other times it heppens because we force it to happen, typically by bombarding atoms with high energy neutrons.

    I've already explained why gold is gold in color.
     
Loading...