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What is the Smallest Piece of Matter We Can Observe?

  1. Jun 14, 2014 #1
    I was just recently listening to a radio program, where a scientist said that we cannot observe electrons visually, but know they exist from their effects. That got me wondering...

    What is the smallest piece of matter that we DO have the capability of seeing? And, also, how much of what exists is beyond our current scope of observation?
  2. jcsd
  3. Jun 14, 2014 #2
    The answer to this question depends on if you mean "see/observe with our eyes" or "observe/examine with instruments (i.e. equipment)". So which of these do you mean? :smile:
  4. Jun 14, 2014 #3


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    Look up atomic force microscope, and related images.
  5. Jun 14, 2014 #4


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    What you are being asked to explain here is elaborate if you mean by seeing as in with the naked eyes, unassisted by any other means.

    If this is yes, then the answer is the the size of the shortest wavelength in the visible spectrum of light. This is because to "see" something with your eyes, the object must either have its own light, or is able to reflect light from an external source. And the smaller the object, the shorter the wavelength of light that is needed to detect that object. Since we are using our eyes, then it will be the shortest wavelength that our eyes can detect, which is towards the violet/indigo region.

    If you are asking about what we can see/detect in general with assistance of devices, then STM/AFM techniques have allowed use to look at Angstrom scale resolution.

  6. Jun 14, 2014 #5


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  7. Jun 14, 2014 #6


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    Interesting....how do you know radio exists if you can't see it...?
  8. Jun 14, 2014 #7


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    I still think you have to define "seeing". We can't see some galaxies using visible light. If we use a radio telescope to convert the radio data to a visible image does that count as seeing?

    If you want to know what the smallest thing is you can see with regular visible light perhaps try..


    As others have pointed out, you can make images of smaller objects using SEM and the like but is that "seeing" according to your definition?
  9. Jun 16, 2014 #8
    Haha! Let's say both!! :tongue: That'd be neat to know!

    Interesting. Out of curiosity, what are some things that are on the "Angstrom" scale of size?

    Also, have we ever "seen" (with either human eye or a device assisting it) things like atoms before?
  10. Jun 16, 2014 #9
    Actually it's spelled Ångström, with "Å" and "ö", which are different letters than "A" and "o". Just a side note.
  11. Jun 16, 2014 #10


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    An angstrom is 10^-10 meters. This is roughly in the molecule/single atom size (where the electrons orbit) range.
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