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Thread: solid matter.

  1. #1 solid matter. 
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    Often I feel reluctant to post, in the physics sub forum, as I feel it should be left to those with a good grounding in the subject. I do believe there are a number of posters here, including, of course, the good Doctor, who fall into that category.
    I have a question about something I read some time ago.
    I think the book was called "The Mysteries of Modern Science" by Brian Stableford and I am pretty sure the chapter was titled "The Atomic Wilderness". I may have mentioned the book before.
    In the chapter Stableford describes the electron as "an idea, not an object". Sounds good but probably doesn't mean very much. I assume he means we know a lot more about how it behaves than what it actually is.
    Later on, in the same chapter, he goes on to say that "solidity is a property of matter in aggregate, not of matter per se".
    We were even taught, in school, that the atom is largely empty space so what gives matter "in aggregate" its solid feel and appearance?


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    In layman's terms (which are the only ones I have access to in physics) electrical repulsion. Atoms are held apart by the like charges in their electron 'shells'. Remove the electrons - and the protons - as is the case with a neutron star - and you wind up with something that is decidedly solid.


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  4. #3 Re: solid matter. 
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    Quote Originally Posted by Halliday
    We were even taught, in school, that the atom is largely empty space so what gives matter "in aggregate" its solid feel and appearance?
    The Heisenberg uncertainty principle.
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  5. #4 Re: solid matter. 
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    Quote Originally Posted by Halliday
    We were even taught, in school, that the atom is largely empty space
    Yes, so is the standard teaching, and the standard popularizers believe it.
    However, this standard believing that each electron is much smaller than the entire atom, is not supported by any experiment.
    And the proves of the contrary are many.
    Many of them are in the field of solid state physics.
    For instance, in metals, deep electrons are approx the size of the atom (each), and the conduction electrons are far bigger. They interact with phonons, which can never be smaller than a dozen of interatomic distances.
    And so on.

    See also the Compton diffusion of gamma or X photons by electrons in a solid, where never the photon nor the electron become corpuscular.

    Molecules and solids exist because of the sharing of some electrons.
    The most amazing phenomenon for those who believe in corpuscles, is the existence of dye molecules. There the resoning electron is approx the size of the whole molecule.
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    All we have are mathematical models of reality at the size of an electron. We will certainly never see one or touch one.
    As to wether it is solid or not, it has some properties and effects best described by solids such as scattering, but it can also be diffracted like a wave, or even smeared out as a probability cloud.
    Our best theories are application specific, they work for one circumstance but may not for another. Don't follow the theory explicitly but try to have some understanding of the undelying physics to detemine application suitability.
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    My Somalian chemistry partner describes an atom as "something that has mass and takes up space".
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    Quote Originally Posted by Geo
    My Somalian chemistry partner describes an atom as "something that has mass and takes up space".
    That really narrows the field down. I can almost visualise the object from your description.
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    A better description might be "something that has a very tiny bit of mass and takes of a lot of space
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    Another thing is the Pauli Exclusion Principle.
    Don't bother visiting my Earth Sciences forum, it died a death due to lack of love
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    Quote Originally Posted by MeteorWayne
    A better description might be "something that has a very tiny bit of mass and takes of a lot of space
    That is better!
    I think I can actually see it now.
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  12. #11  
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    Quote Originally Posted by Geo
    My Somalian chemistry partner describes an atom as "something that has mass and takes up space".
    Difficult questions have simple, easy-to-understand, wrong answers.
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    Quote Originally Posted by MigL
    All we have are mathematical models of reality at the size of an electron.
    I am sure that is true.
    I wonder if we will ever be able to give an actual physical description, in words, of sub atomic objects such as the electron, or are mathematical models the limit and does it matter if that is the case?
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    I'd vote for doesn't matter. Our everyday language isn't really precise enough to do something so exotic justice.
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    Quote Originally Posted by MagiMaster
    I'd vote for doesn't matter. Our everyday language isn't really precise enough to do something so exotic justice.
    Interesting you mention the precision of language!
    Ages ago, I read a passage somewhere and the writer stated there were no words, in any language presumably, that could properly describe sub atomic particles.
    I know I was impressed, by the statement, because I remembered what was said much later.
    These days, I have no idea whether the comment is accurate or not.
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    I don't doubt that you could describe it. I just think that it'd take a large enough number of words that most people would have trouble putting it all together.
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    Quote Originally Posted by MagiMaster
    I don't doubt that you could describe it. I just think that it'd take a large enough number of words that most people would have trouble putting it all together.
    You are probably right, but it is fairly clear from what I have read here, and other sources, that popular explanations of subjects (basically non-technical accounts using mainly words) such as particle physics and general relativity can never approach the depth of understanding which can be achieved using maths rather than a language based solely on words.
    If I can return to the electron; there is clearly something that exists we call the electron. If it exists it should eventually be possible to describe it and altho' by far the best description, of its activity/behaviour, is given using mathematical techniques it does not seem possible that mathematical language will ever be able to furnish a physical "picture" of this type of sub atomic particle.
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    Quote Originally Posted by Halliday
    You are probably right, but it is fairly clear from what I have read here, and other sources, that popular explanations of subjects (basically non-technical accounts using mainly words) such as particle physics and general relativity can never approach the depth of understanding which can be achieved using maths rather than a language based solely on words.
    Mathematics itself not only can be, but is, described completely using words. Mathematics is primarily a very precise language. The symbology of mathematics is nothing more than a convenient shorthand designed to convey a lot of information in a very concise manner. It is just a substitute for a great many words.

    The whole point of mathematics are the concepts. Those concepts are described in words. The mathematically illiterate simply fail to understand the words.




    Quote Originally Posted by Halliday
    If I can return to the electron; there is clearly something that exists we call the electron. If it exists it should eventually be possible to describe it and altho' by far the best description, of its activity/behaviour, is given using mathematical techniques it does not seem possible that mathematical language will ever be able to furnish a physical "picture" of this type of sub atomic particle.
    Mathematics provides the "physical picture". See above.

    Most often when an appeal is made for a "physical picture" is made what is actually requested is "an explanation that makes me think I understand when in fact I am clueless".
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    Quote Originally Posted by Halliday
    If I can return to the electron; there is clearly something that exists we call the electron. If it exists it should eventually be possible to describe it and altho' by far the best description, of its activity/behaviour, is given using mathematical techniques it does not seem possible that mathematical language will ever be able to furnish a physical "picture" of this type of sub atomic particle.
    I think you'd need to define "physical picture" in enough detail that you could be sure you had one in the end, and I think if you did that, you couldn't rule out the mathematical view.
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    Then it is true to say I don't really understand the picture given by mathematics.
    I have been fascinated by the electron since I read an article ages ago, in a science magazine, in which it was described as a "dimensionless mathematical point". I don't know if that means anything but it sounds good!
    I would like a photograph, drawing or painting (preferably by Vermeer) of the electron, but I understand this is not possible even if Vermeer were still around.
    Is it likely that technological advances will ever enable us to produce a clear (non fuzzy) physical image of the structure/appearance of an object such as the electron?
    Given that I lack a proper mathematical background the question may not make any sense.
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    I think that'd be a bit like the photograph of the pillars of creation. It looks great, but it's not what they actually look like. It's a false color image, and unless you know a lot about astrophysics, even having the coloring explained wouldn't really help explain what's really going on there.
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    Quote Originally Posted by MagiMaster
    I think that'd be a bit like the photograph of the pillars of creation. It looks great, but it's not what they actually look like. It's a false color image, and unless you know a lot about astrophysics, even having the coloring explained wouldn't really help explain what's really going on there.
    Apart from the "false colour image" I assumed this photograph does show, at the distance of our planet, what the Pillars of Creation look like and I certainly would settle for such an "image" of the electron.
    I agree, of course, that photos/images do not necessarily come even close to explaining everything that is really going on.
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    Quote Originally Posted by DrRocket
    Mathematics itself not only can be, but is, described completely using words. Mathematics is primarily a very precise language. The symbology of mathematics is nothing more than a convenient shorthand designed to convey a lot of information in a very concise manner. It is just a substitute for a great many words.

    The whole point of mathematics are the concepts. Those concepts are described in words. The mathematically illiterate simply fail to understand the words.
    Thank you for this post. This is one of those statements that once made appears self evident. It has altered my perception of mathematics just enough to encourage me to take another stab at the basics.
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  24. #23  
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    Quote Originally Posted by Halliday
    Quote Originally Posted by MagiMaster
    I think that'd be a bit like the photograph of the pillars of creation. It looks great, but it's not what they actually look like. It's a false color image, and unless you know a lot about astrophysics, even having the coloring explained wouldn't really help explain what's really going on there.
    Apart from the "false colour image" I assumed this photograph does show, at the distance of our planet, what the Pillars of Creation look like and I certainly would settle for such an "image" of the electron.
    I agree, of course, that photos/images do not necessarily come even close to explaining everything that is really going on.
    Well, you can see a similar kind of picture here. It's a rendering, not a picture, but I'd say it's similar.
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    Quote Originally Posted by MagiMaster
    Well, you can see a similar kind of picture here. It's a rendering, not a picture, but I'd say it's similar.
    Reading that gives some idea of how complex any proper study of sub atomic particles really is and how far divorced from common sense and our everyday experiences in the "macro" world.
    In many ways my posts here amounted to no more than an almost childish request for a "picture" and whether new technology would ever make this possible.
    Years ago the books used to state it was impossible to "see" the atom. Back in the mid 1990's (pre internet for me) I saw a photo in a book and phoned the photographer (an American scientist working in the States) who kindly offered to send me a copy which I still have.
    The title of the photo was "Astrid Unclothed" and Astrid was shown as a small, very pretty, blue dot-in fact, a single barium atom. Since then I have seen other images of single atoms and altho' there is little detail perhaps the "picture quality" will improve in the future.
    The photographer, of the barium atom, was a German scientist called Hans Dehmelt, who moved to the USA, and the photo appeared in the book "Taming the Atom" by Hans Christian Von Baeyer. He was the scientist, in the USA, who sent the photograph.
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