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Matter's solidity ?

by k_snelson
Tags: matter, solidity
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k_snelson
#1
Mar3-04, 10:03 AM
P: 20
Where does solidity begin?

The familiar saying is: “two things can’t occupy the same space at the same time” -- true of matter but not true of lightwaves that pass through one another without obstruction like ghosts. That matter keeps other matter out is of course true of even the tiniest pieces of matter – say, a crowd of helium atoms that have only two electrons each.

Explanation #1 for this phenomenon is that when the atoms bump into one another the electrons inside are moving so fast that they create an external electrical repelling barrier. Another explanation is that the bumping atoms refuse interpenetration because of the Pauli exclusion principle – that their electrons have the same sets of quantum numbers.

The quantum numbers explanation is hard to argue with because who knows what it means physically to say that separate atoms’ electrons have identical quantum numbers? But a mixture of argon and helium would put atoms of different quantum numbers up against one another wouldn’t it?

Explanation #1, that they carve out a blur of electrical shield is easier to question since it is a physical explanation whereas the mathematics of the charge cloud picture admits nothing about electron motion or the trajectories. Also, if the charge clouds themselves act like solids, atom-to-atom, why wouldn’t they act like solids, electron-to-electron, inside the atom?

I bring this subject up because I believe it deserves being thought about by thoughtful people.

The explanation for matter’s solidity that appeals to me is that the individual electron’s de Broglie waves are by their nature impenetrable to one another. That they are the threshold of solidity.

Any thoughts about this matter?
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chroot
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Mar3-04, 03:25 PM
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Two electrons in two different atoms are in two totally separate systems. Two different electrons in two different hydrogen atoms CAN have the same quantum numbers, because a set of quantum numbers only applies to one single (bound) system.

The reason solids are solids at normal conditions is due entirely to electrical repulsion of the electrons.

When you get to very high pressures, such as inside a white-dwarf star, the free electrons actually will begin to be supported against collapse by "degeneracy pressure," which is simply the lack of quantum states. Simply put, you can't squeeze a white dwarf any more because the fermionic electrons won't allow it.

- Warren
k_snelson
#3
Mar3-04, 04:42 PM
P: 20
Originally posted by chroot
The reason solids are solids at normal conditions is due entirely to electrical repulsion of the electrons.- Warren
_________________________________

That's what doesn't make sense: If we say that two neighboring atoms' electrons cause repulsion between the atoms don't we also have to say that they are equally attracted to one another's nuclear positive electrical fields? After all, we're talking about two electrically neutral atoms?

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Mar3-04, 04:57 PM
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Matter's solidity ?

Originally posted by k_snelson
Where does solidity begin?

The familiar saying is: “two things can’t occupy the same space at the same time” -- true of matter but not true of lightwaves that pass through one another without obstruction like ghosts. That matter keeps other matter out is of course true of even the tiniest pieces of matter – say, a crowd of helium atoms that have only two electrons each.

Explanation #1 for this phenomenon is that when the atoms bump into one another the electrons inside are moving so fast that they create an external electrical repelling barrier. Another explanation is that the bumping atoms refuse interpenetration because of the Pauli exclusion principle – that their electrons have the same sets of quantum numbers.

The quantum numbers explanation is hard to argue with because who knows what it means physically to say that separate atoms’ electrons have identical quantum numbers? But a mixture of argon and helium would put atoms of different quantum numbers up against one another wouldn’t it?

Explanation #1, that they carve out a blur of electrical shield is easier to question since it is a physical explanation whereas the mathematics of the charge cloud picture admits nothing about electron motion or the trajectories. Also, if the charge clouds themselves act like solids, atom-to-atom, why wouldn’t they act like solids, electron-to-electron, inside the atom?

I bring this subject up because I believe it deserves being thought about by thoughtful people.

The explanation for matter’s solidity that appeals to me is that the individual electron’s de Broglie waves are by their nature impenetrable to one another. That they are the threshold of solidity.

Any thoughts about this matter?
This will be a very quick reply since I am in the middle of an experimental run, but I feel compelled to reply due to your statement that seems to indicated that this issue has not been sufficiently understood. ("... deserves being thought about...")

If you look in a Solid State Physics textbook, you will see EXACTLY just what you are questioning here. In particular, pay attention to the section on "tight-binding approximation", in which there is a substantial overlap of the electronic wavefunction with neighboring atoms. You will see that it isn't as trivial as you imagine. When two atoms are close enough to sense each other, the independent atomic energy levels that worked for one atom are no longer the valid eigenfunctions for the two atoms. The wavefunction, and energy/orbital states start to hybridize and a whole set of new good quantum numbers appear!

And oh, to kill 2 birds with one stone, the same book will also tell you why a hexagonal closed-packed structure of diamond produces a strong and stable crystal structure.

Zz.
k_snelson
#5
Mar3-04, 07:58 PM
P: 20
When two atoms are close enough to sense each other, the independent atomic energy levels that worked for one atom are no longer the valid eigenfunctions for the two atoms. The wavefunction, and energy/orbital states start to hybridize and a whole set of new good quantum numbers appear!
The atom is a genuine physical object down in that submicrospace and it is performing according to its own logical rules. What was missing from the beginning, from Bohr on, was a fitting analogy to work from. Since none came along, the small band of physicists in Germany agreed to avoid the riddle by accepting Max Born's interpretation -- waves of probability -- and the physical questions were easily swept under the rug. Yes, swept under the rug and avoided by the red herring excuse of the Heisenberg principle. Eventually science will revisit the original questions since fashions don't last forever.

"And oh, to kill 2 birds with one stone, the same book will also tell you why a hexagonal closed-packed structure of diamond produces a strong and stable crystal structure."
Please note: the diamond lattice is not a hexagonal closed-packed structure. Each carbon atom is connected to only four neighbors, not twelve.
ZapperZ
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Mar4-04, 06:52 AM
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Originally posted by k_snelson
Not in terms of eigenfunctions but in terms of logical structure. Please. It's often the case when logic fails one can always make a defense in terms of standard models which need not be logical, only mathematical. That's been the nature of the debate in quantum physics since 1930 and the abandonment of physical models.

Again, for most thinking people, if one cannot provide an answer with logic then the answer can never be convincing.

But you are making one huge assumption that your method of thinking, and your "philosophy" of what the universe should look like is correct. The "mathematics" as you so clearly dissed, isn't just a set of mindless expression. If I look at Gauss's law, it isn't just a set of mathematical symbol and operations - it MEANS something. A musican looks at a set of musical notes on paper NOT as simply notes - they represent sound. The same way with mathematical expressions in physics - they aren't just math, they represent a concept, ideas, principles, etc.

While atoms, molecules, etc, existed before QM, many of their properties could not be completely explained till QM. The existence of an energy gap in the H2 molecule is one clear examples. Chemists knew about this way back when before QM. But it requires QM's formulation to clearly show the existence of bonding and antibonding bands and the origin of such gap! What is more logical than a set of ideas and concept that are verified QUALITATIVELY and QUANTITATIVELY by experiment?


There is a physical object down in that submicrospace and it is performing according to its own logical rules. What was missing from the beginning, from Bohr on, was a fitting analogy to work from. Since none came along, the small band of physicists in Germany agreed to avoid the riddle by accepting Max Born's interpretation -- waves of probability -- and the physical questions were easily swept under the rug.
Unfortunately, physics doesn't work via analogies. Analogies are misleading and at best, inaccurate. They do not convey the full impact of any ideas in physics. Analogies and examples are techniques used in pop-sci books to try to explain physics. This is absolutely insufficient to understand any concept in physics.

One thing that many people somehow are not aware of (and this comes up again and again when dealing with quackeries when they accuse one of not "thinking on his/her own" or "think outside the box" or "think beyond what is in the textbooks") is that, BY DEFINITION, practicing scientists (and physicists in particular) work on things that either are not well-understood, have no current explanation, are not fully verified yet, or something completely new! We don't normally work on things we already understand, or stuff that we see in textbooks! <shocking, I know!> This inevitably means that we HAVE to think beyond what we already know and try to look out for things, explanations, and ideas that are beyond what we have! I do this EVERYDAY, and it is part of my job. So you will understand if I find it rather amusing and a little bit insulting that I am being told to do this just because I pointed out that what you're asking is already in textbooks that all condensed matter physics students have. And till you actually look them up, you should not make simple judgement that they are nothing more than just mindless mathematics.

Zz.

Edit: Fixed Quote tags.
Integral
k_snelson
#7
Mar4-04, 07:31 AM
P: 20
And till you actually look them up, you should not make simple judgement that they are nothing more than just mindless mathematics.
I can't remember saying that.

Unfortunately, physics doesn't work via analogies. Analogies are misleading and at best, inaccurate. They do not convey the full impact of any ideas in physics. Analogies and examples are techniques used in pop-sci books to try to explain physics. This is absolutely insufficient to understand any concept in physics.

All models of the atom are based on analogies of some type. The charge cloud model assumes people know about clouds or vapor. That's an analogy. The Bohr model was an analogy of the solar system. The de Broglie model was based on standing waves from known mechanical systems. The vector models in spectroscopy are based on spinning tops. It's the only way to talk about the invisible atom. Even physicists I've known explain anything and everything in terms of analogies. The big bang's analog is of an explosion. Every physical form or event has an analogy on which people build theories. Einstein wondered what it would be like to travel in a beam of light. Kekule dreamed of snakes devouring their own tails. If one lacks a sense of association between similar principles there is little hope in being creative.That's what creative talent of is all about.
ZapperZ
#8
Mar4-04, 07:46 AM
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Originally posted by k_snelson
I can't remember saying that.




All models of the atom are based on analogies of some type. The charge cloud model assumes people know about clouds or vapor. That's an analogy. The Bohr model was an analogy of the solar system. The de Broglie model was based on standing waves from known mechanical systems. The vector models in spectroscopy are based on spinning tops. It's the only way to talk about the invisible atom. Even physicists I've known explain anything and everything in terms of analogies. The big bang's analog is of an explosion. Every physical form or event has an analogy on which people build theories. Einstein wondered what it would be like to travel in a beam of light. Kekule dreamed of snakes devouring their own tails. If one lacks a sense of association between similar principles there is little hope in being creative.That's what creative talent of is all about.
But these so-called analogies are BACKED UP by an underlying mathematical description that is accurate and unambiguous. While people debate what QM really means, NO ONE questioned the accuracy and validity of the mathematical formulation of it! There is a distinct difference between those two! What you espousing is that these mathematical description is secondary! It is not. It comes first, the analogies comes SECOND (or even third or fourth!). Every principle, quantitities, and ideas in physics HAS an underlying mathematical desciption. I cannot simply use the word "fermion" in any way I like, because the term has a set of clear definitions that are described mathematically.

What is lost here is my original reason for the incursion into this string - that you are asserting that the problems of atoms coming in close contact with each other have not been sufficiently addressed, as if it has been swept under a rug. I was trying to point out that equating your state of knowledge with the actual state of knowledge in physics may not be the most accurate thing in the world to do. From your responses, I am guessing that you have not thought of the possibility of looking up these things in a solid state physics text. Unfortunately, when I suggested that, I get accused of not being able to think on my own.

Zz.
k_snelson
#9
Mar5-04, 01:14 PM
P: 20
Originally posted by ZapperZ
But these so-called analogies are BACKED UP by an underlying mathematical description that is accurate and unambiguous. While people debate what QM really means, NO ONE questioned the accuracy and validity of the mathematical formulation of it! There is a distinct difference between those two! What you espousing is that these mathematical description is secondary! It is not. It comes first, the analogies comes SECOND (or even third or fourth!).
It seems to me the experiment comes first, then the analogy, then the mathematics. Rutherford's people first bombarded the gold foil. From that experiment they learned there was a tiny nucleus. The implication that the electrons must be occupying the rest of the space prompted an imagined atom like a solar system. Then Bohr brought that idea together with the Balmer lines and the model was born. The math came last. Now and for many years the model is said to be all wrong because of those annoying orbits.

I take it that all the capital letters are for emphasis?
ZapperZ
#10
Mar5-04, 02:46 PM
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Originally posted by k_snelson
Originally posted by ZapperZ


It seems to me the experiment comes first, then the analogy, then the mathematics. Rutherford's people first bombarded the gold foil. From that experiment they learned there was a tiny nucleus. The implication that the electrons must be occupying the rest of the space prompted an imagined atom like a solar system. Then Bohr brought that idea together with the Balmer lines and the model was born. The math came last. Now and for many years the model is said to be all wrong because of those annoying orbits.
And you would be wrong if you think this is exclusively how knowledge in physics develops. One clearest example is antimatter that first came out of Dirac's formulation of QM. No such thing was ever observed experimentally, or even thought of, before his formulation.

Secondly, I really don't understand this "analogy" stuff. Analogies are simply a small subset, and application, or simply some resemblance of some THING. It is NOT the thing in itself. It is a way to convey some parts of an idea to someone who does not know, or have no ability, to know the thing. Pop-sci authors do this all the time. As Integral has pointed out in another string, there is a difference between learning physics and learning ABOUT physics. I would not be quick to make any definite statements about a subject matter if all I have acquired about that subject is simply via pop-sci books, or even conversation with people in that area. If understanding physics is that easy, everyone could do it. The essence of physics often lies in the subtleties in many areas - one does not understand it until one graps these subtleties.

Take note that there is a difference in "analogies" and constructing a "model" that represents the mathematics involved. Even the Bohr-Sommerfeld quantization model that was supposed to represent the atomic orbits came out of classical, mathematically-developed mechanics! It didn't come out of thin air with ambiguous hand-waving arguments. There must be both qualitative and quantitative descriptions. Physics just doesn't say that everything that goes up, must come down. It must also say when and where it will come down!

While "analogies" and "visualization" can help to convey an idea, one should never fool oneself into thinking that these are the whole idea and that one has gotten all there is to know about that idea.

Zz.
k_snelson
#11
Mar5-04, 10:31 PM
P: 20
Dear Z,

We've gone over this same territory several times it seems to me. I don't quite understand what motivates you to spend your time surfing this physics forum apparently looking for arguments to win. For my part I am looking to get some useful feedback on the work I've done and it occurred to me when I found this site a week or so ago it might be just the place.

All you have to say is (and why you even respond to me is a mystery) " read the standard model." By the way, I have no "pop-sci" books as you call them but I have a sizeable library of serious physics and spectroscopy books as well as history of science and philosophy of science books, all of which have interest me very much for over forty years.

I know a great deal about what's behind the standard model minus the mathematics; to which you will reply, "BUT THE MATH IS ALL" (in caps). The fact is the math is not all. The ideas that lie behind the math are essential as well. Math can make any misconception look feasible. Think of Ptolemy's work.

I repeated the following Einstein quote somewhere else recently: "All physical theories, their mathematical expression apart, ought to lend themselves to so simple a description that even a child could understand them."

I know a great deal about the laws of structure and you know a great deal, it seems, about the mathematics of QM. The math you are committed to does not describe an intelligent structure. The standard model has no diffentiated tension and compression forces as required by every other structure anywhere. The standard model provides no way to understand spatially what a "shell" is or where all of those hundred or more electrons in a heavy atom are located -- except of course on the flat page of a chemistry text. It's all in the mathematics, you say. Many people, not only cranks like me, share similar concerns about the standard model. Yes, even as Erwin Schroedinger did.

I am only assuming that you know what my art is about. If you don't it must be doubly puzzling why I come on so strong in this subject.
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Mar6-04, 06:46 AM
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Originally posted by k_snelson
Dear Z,

We've gone over this same territory several times it seems to me. I don't quite understand what motivates you to spend your time surfing this physics forum apparently looking for arguments to win. For my part I am looking to get some useful feedback on the work I've done and it occurred to me when I found this site a week or so ago it might be just the place.
And it seems to me that I have explained this several times. My original reason on why I even responded to this was because you make a blatant statement that we don't know, or have not thought about, why and how the atomic model behave as they come closer to each other, etc...etc. I objected to your equating your state of knowledge with the state of knowledge in the physics world. As a physicist, even *I* would not make such a bold statement.

And you continue to do it too. In that last posting I responded to, you make a claim that experiment comes first, analogies come next, and "mathematics" comes last. Again, I disputed that by giving you one very clear example where you are wrong. I did not know that I shouldn't do that, or did you prefer to continue believing that is how all of physics is done?

BTW, I did stopped responding to you after the message that was, for some reason, deleted. I see no reason to continue with this, since obviously, based on what you perceived as an "age difference", we obviously are in different "orbits" and seem to agree to disagree. However, that message was replaced by the "experiment-analogy-mathematics" message, which is unfortunate.

All you have to say is (and why you even respond to me is a mystery) " read the standard model." By the way, I have no "pop-sci" books as you call them but I have a sizeable library of serious physics and spectroscopy books as well as history of science and philosophy of science books, all of which have interest me very much for over forty years.

I know a great deal about what's behind the standard model minus the mathematics; to which you will reply, "BUT THE MATH IS ALL" (in caps). The fact is the math is not all. The ideas that lie behind the math are essential as well. Math can make any misconception look feasible. Think of Ptolemy's work.

I repeated the following Einstein quote somewhere else recently: "All physical theories, their mathematical expression apart, ought to lend themselves to so simple a description that even a child could understand them."
I will ask you seriously about this: Do you really, truly expect, that the theory of atomic orbitals, superconductivity, magnetism, CP violation, Noether theorem, etc, should and could be understood by a child? Because if you do, then you are correct, it is entirely MY mistake to actually try to engage with you in this conversation.

Zz.
k_snelson
#13
Mar6-04, 11:20 AM
P: 20
Alright Zapper, you’ve zapped me.

Thanks for your warm encouragement.
Integral
#14
Mar6-04, 08:57 PM
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Mr. Snelson,
You have an admirable set of qualifications, but nowhere did I see any mention of graduate work in physics. Did you forget to list it?
I am sure that you feel that the pictures of your imaginary atoms are quite attractive, (I am not enthralled) but do not delude yourself that they are any more a picture of an atom then the scribblings of a 2 yr old.

I know a great deal about what's behind the standard model minus the mathematics;
And I own a Ferrari, minus the body, and motor and wheels.

MATH IS ALL! To say that you understand it except for the math is to admit that you have NO depth of understanding.
k_snelson
#15
Mar7-04, 11:02 AM
P: 20
Originally posted by Integral
Mr. Snelson,
You have an admirable set of qualifications, but nowhere did I see any mention of graduate work in physics. Did you forget to list it?
I am sure that you feel that the pictures of your imaginary atoms are quite attractive, (I am not enthralled) but do not delude yourself that they are any more a picture of an atom then the scribblings of a 2 yr old.
Did you actually read the piece or do you just look at pictures.
If you did read it where's your imagination? What did you ever invent or achieve in your profession? Where are your medals?

And I own a Ferrari, minus the body, and motor and wheels.
So you got taken?
Integral
#16
Mar7-04, 01:22 PM
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Mr. SNelson,

Now who is throwing around the qualifications ball?

I admire your achievements, but all the medals in the world as an ARTIST do not qualify you to speak with authority in any field other then metal sculpture. No, I did not read all of your paper. What I did read failed to impress me. I guess I have a different taste then you, I did not see much artistry in the images nor did I feel that most of them where meaningful representations of atomic structure.

I assume you came here looking for feedback, then I may be wrong, perhaps you came here looking for "gee whiz" types of response. I am disappointed in your ability to accept feedback and you appear to be disappointed in the lack of enthusiasm your ideas have been greeted with.

This is really to bad. If you came here with the goal of furthering your knowledge you would find a positive experience. Unfortunately we see to many with a partial or poor understanding of Physics come in here and attempt to preach their limited knowledge as something new and "out of the box". In reality they are simply stuck in a dusty corner, with no reasonable idea of where the box is. Many of us here tired of this attitude long ago and show little patience with it.

There are many very knowledgeable people posting on this forum. You have a choice to make, to argue the current state of knowledge with people knowledgeable in the field, or ask questions which could further your state of knowledge. Choosing the former is a huge mistake, these forums are a wondrous thing indeed, you have the opportunity to ask questions and receive answers from Graduate students, full professors and even high school students who like you have make a hobby or perhaps a career of thinking of Physical Matters.

I am very honored to have someone of your credentials posting here, perhaps though you need to understand the leveling power of the internet. On the internet ANYONE can claim to be anything, one learns to be skeptical of touted qualifications. I have learned that it is best to simply sit on qualifications, let you knowledge shine through in the content of your posts, rather then claiming knowledge and expecting all to bow before your obvious (to you) merits.

You must understand that those of us that have toiled through the math have not always had that perspective. What we have had is the 'ah-ha' experience of seeing and understanding the meaning and depth the math provides. For you, who has never walked that path, to claim it is unnecessary, is a blind man claiming color does not exist.

As for being taken on the Ferrari, I can say the same about you and your understanding of Physics... You have been taken.
k_snelson
#17
Mar7-04, 03:48 PM
P: 20
Originally posted by Integral
Mr. SNelson,

Dear Integral and ZapperZ too,

I haven't claimed anything except that I've produced an artist’s analog model of the atom based on de Broglie’s original model. How would I have known about de Broglie’s model if I hadn’t studied it in the literature of science? Is what I’m doing some kind of criminal activity in a free country?

I’m smiling because there’s nothing I’ve done in life that has gotten such an angry reaction as this. I feel as if I’m confronted, not by scientists, but by religious extremists outraged by the audacity of an unwashed infidel.

That you guys haven’t even read the paper before you’re outraged by it must be an example of good science.
ZapperZ
#18
Mar7-04, 04:00 PM
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Originally posted by k_snelson
Originally posted by Integral
Mr. SNelson,

Dear Integral and ZapperZ too,

I haven't claimed anything except that I've produced an artist’s analog model of the atom based on de Broglie’s original model. How would I have known about de Broglie’s model if I hadn’t studied it in the literature of science? Is what I’m doing some kind of criminal activity in a free country?

I’m smiling because there’s nothing I’ve done in life that has gotten such an angry reaction as this. I feel as if I’m confronted, not by scientists, but by religious extremists outraged by the audacity of an unwashed infidel.

That you guys haven’t even read the paper before you’re outraged by it must be an example of good science.
Do me a favor. Please read the message where you posted your "paper". Now pay careful attention - did I, or did I not, responded to that? C'mon, you can do it. Tell me, did I ever, EVER, followed up with any comments, any response, etc, TILL NOW?

I said NOTHING. I have said nothing since then since I've concluded that this is a waste of time and effort. But you continued to include me in ALL of your subsequent diatribe, even when you're replying to Integral's comments. "That you guys haven't even read..." What you guys? Where did I said that I've read, or haven't read your paper? Where did I make any comments about it?

Zz.


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