Talk:Atom/Archive 2

message: The text in Practical Uses of the atom felt very superfluous.  It was far too vague. (written by Kurzon)
*I agree ... except for the fact that the pending tasks for this article was to contain information on "atoms in industry" fusion, fission, etc.  Removing the Practical Uses section simply leaves this task "still pending".  And creating a detailed account of fusion, fission, and the atom in different fields of science is redundant since there are specific articles discussing these subjects.  How does removal of the Practical Uses section help with alleviating the pending task of describing fusion, fission, and atoms in industry?  Explain instead how to improve.  I didn't like the section itself except that it met the requirements for the pending tasks.  It was a "jumping off point" for further investigation of these areas without going into details.  Removing it solves nothing.  Now the task still remains.--Voyajer 21:59, 14 December 2005 (UTC)
thread_title: Removal of Practical Uses section

message: well?
Pece Kocovski 07:53, 3 February 2006 (UTC)
replies: text: There's no simple answer. Just read the article and look at the history. Itub 16:57, 3 February 2006 (UTC)
thread_title:  who discovered the atom? 

message: Has anyone seen them? I belived not, but recently I was told a profesor of mine owns a Picture of one, or so he claims, taken by a electronic microscope. Can anyone tell me if it is true? If so, Why isn't there a picture of one? Thnk you.--201.208.149.194 02:42, 7 February 2006 (UTC)
replies: text: Yes, there are images. There is not a good one in the Wikimedia commons. Presumably people with expensive equipment are not keen on letting out their expensive images. Here's a link to a famous series from IBM: Atom Corral -- Xerxes 18:22, 7 February 2006 (UTC)
thread_title: Atoms?

message: My main goal when editting this section was to clearly explain the logical steps scientists made over the years in developping atomic theory, in a sweet and simple manner that is clear to the layman, ie people who have a decent IQ but are not physics students who have lived and breathed this stuff for years.  Throwing lots of unclear jargon around as well as vaguely referencing contributions without explaining their significance goes against this principle.  The following paragraph is a good case in point:
"The ad hoc Bohr model would eventually be replaced by the Erwin Schroedinger's Schroedinger equation in 1925. Together with the Pauli exclusion principle, this allowed study of atoms with great precision. Even today, these theories are used in the Hartree-Fock method to determine the energy levels of atoms. Further refinements of quantum theory such as the Dirac equation and quantum field theory made smaller impacts on the theory of atoms."
What the heck is the Schroedinger equation? Why did it replace Bohr's concept?  Just how did that and the Pauli exclusion principle allow the study of atoms with great precision?  All this paragraph really says in the end is that the model of the atom kept developing after Bohr.  I feel this is inadequate for an informative encyclopedia.  Perhaps doing these developments justice would require an inordinate amount of maths and explanation, but we should at least try to offer something sweet and simple.Kurzon 19:48, 7 February 2006 (UTC)
replies: text: Well, I haven't got my atomic physics book on me at the moment, so I couldn't remember the major failings of the Bohr model. Inability to calculate transition rates is one. Inability to deal with multielectron atoms is another. What did you have in mind? -- Xerxes 20:12, 7 February 2006 (UTC)

text: Yes, I agree that this is a better picture. Itub 19:02, 10 February 2006 (UTC)
replies: text: One thing I think this image really fails to convey is the fact that atoms are spherical. Any ideas on how to improve it in that respect would be appreciated. -- Xerxes 19:24, 10 February 2006 (UTC)

text: That's hard, because 3d pictures of orbitals tend to look like solid balls (or balloons). I don't know how one could make a diffuse cloude look 3d. Itub 20:31, 10 February 2006 (UTC)
replies: text:  When this is resolved, could the same image be placed at atomic nucleus, please! Olin 03:36, 29 March 2006 (UTC)
thread_title: History of Atomic Theory

message: 1) The atom is not empty space. It is densely filled by the electron cloud.
2) The Bohr model was not constrained to cicular orbits. It also handled elliptical orbits of fixed angular momentum.
-- Xerxes 20:21, 7 February 2006 (UTC)
replies: text: Both points are debatable: 1) there may be some electron density everywhere, but I wouldn't call it "densely filled". The probability of observing an electron as a particle in any specific place is very small. 2) the original Bohr model did use only circular orbits. Elliptical orbits were added in the Bohr-Sommerfeld model. The thing that I would say is most inaccurate about the edit in question is that it said that the alpha particles in the Rutherford experiment "struck" the nucleus. Itub 23:45, 7 February 2006 (UTC)
replies: text: Well, it's densely filled in the sense that the electrons are degenerate. There is no physical way to pack more electrons into the space around a nucleus than you already have in the ground state. The history of atomic models could be more detailed tho. Certainly Sommerfeld deserves a mention. -- Xerxes 00:11, 8 February 2006 (UTC)

text: In comparing the theory outlined in this paper with the experimental results, it has been supposed that the atom consists of a central charge supposed concentrated at a point, and that the large single deflexions of the α and β particles are mainly due to their passage through the strong central field. The effect of the equal and opposite compensation charge supposed distributed uniformly throughout a sphere has been neglected.
The emphasis is mine, but the point is clear. -- Xerxes 17:14, 8 February 2006 (UTC)

text: I don't agree. Even if he didn't actually use the word "empty" in that article, it was implied, because electrons were already assumed to be tiny particles at the time, and their mass and charge were known. He talks about electrons moving rapidly around the atom, which can only imply that there was empty space between the nucleus and the electrons. Also, there are literally hundreds of books that explain Rutherford's experiment in terms of empty space: . I haven't found a single book yet that says the contrary. Itub 19:16, 8 February 2006 (UTC)
replies: text: It would hardly be the first time books for a laymen audience picked up a nonsense phrase and ran with it. The volume of an atom is not empty; it's filled with electrons. If Rutherford did not know that in 1911 nor Bohr in 1913, it was certainly understood by Schroedinger in 1923. What is the point of emphasizing a idea that is today known to be incorrect and was only wrongly believed for 12 years (if ever)? -- Xerxes 19:35, 8 February 2006 (UTC)

text: You would call Max Born and Otto Frisch laymen? (Edit: sorry, you were referring to the audience of the books as laymen. In any case, Born's Atomic Physics seems rigorous enough.) They wrote two of the books refered to above. You are just choosing one particular interpretation of quantum mechanics and basically redefining the word "empty" in such a way that there can be no empty space! Yes, you can't pack more electrons, because they are fermions. But you won't have trouble having other types of particles moving freely through the empty space in the atom. And even if a concept were to be disproved, this is a section about the history of atomic theory. You need to discuss each discovery in its proper historical context. In any case you could create a properly referenced article about the Empty atom controversy (if such a controversy exists) and link it from the Atom article. Itub 20:02, 8 February 2006 (UTC)
thread_title: Last reversion

message: As Bensaccount correctly pointed out, the density function of the image was incorrect. I don't think the replacement image had a correct density function either, since it had sharp cutoffs, so I went ahead and made another version. The new version of the image (I think) has the correct electron density profile. The nucleon profile was grepped out of a nucl-th paper. Again, the nucleus is really almost spherically symmetric, but artistic liberties have been taken. The nuclear scale bar is another good feature taken from Bensaccount's image. -- Xerxes 21:38, 11 May 2006 (UTC)
thread_title: Image problem

message: I've failed the article for inclusion in the release because the antimatter section is too short. After this section is expanded, it would be a good idea to add inline references to it, unless the entire article is indeed based on only one textbook. Titoxd(?!? - help us) 01:30, 30 May 2006 (UTC)
replies: text: This makes no sense. Atoms have virtually nothing to do with antimatter. The brief mention in the article is completely appropriate for the relevance of the topic. -- Xerxes 01:47, 9 June 2006 (UTC)
thread_title:  [[Wikipedia:Version 0.5]] 

message: I think that linking to other article is fine but there should be some information on the devlopmanet of the theory, so I have reincluded some of the history section.  I hope it isn't too large! Rex the first talk | contribs 17:06, 18 June 2006 (UTC)
replies: text: I think maybe a link to the article and a mention of who discovered the atom and who came up with the present model are all that are needed. Remember, this article is about the atom, not the history of atomic science. Since this articl is so big, all it needs to do is give a basic understanding of what an atom is, how it works, why it's important, and which articles can tell you more.
I rewrote the historical section into something more condensed.  The previous version was a little long, and not very elegantly written as it was a hack-job of extracts taken from earlier versions of the atomic theory article.  Feel free to correct any mistakes I made, but please keep the section concise and elegant; we have a dedicated article that explains the history of atomic theory. Kurzon 08:28, 11 July 2006 (UTC)
thread_title:  History of atomic theory 

message: If a proton has a net Positive charge, and a neutron has no charge... then how do they stay together!?
(please use my talk page to respond) Tinlv7 18:33, 21 August 2006 (UTC)
thread_title:  How do they stay together!? 

message: I fixed the vandalized page. Should it be tinkered with further by vandals, we should lock it. 03:18, 14 September 2006 (UTC)
thread_title:  Fixed the page 

message: I think there should be a section on how atoms have not been directly observed (afaik), and how they are posited as entities simply because they help explain and unify various scientific models and theories. This, imho, is one of the interesting parts of atomic theory.
:With atomic force microscopes and scanning tunneling microscopes, individual atoms have been visualized in the same way that viruses have (we need some links in this article for that-- I'll get to it). I'm not sure what you mean by "directly observed." No, not with the eyeball. However, a decade or so ago IBM used 35 individual xenon atoms to spell out "IBM" on a metal surface , and that's hard to do if you can't in some way "observe" the individual atoms. Do you think viruses are still just posited entities? DNA molecules? How far down in scale does your philosophical skepticism extend?  SBHarris 17:34, 1 October 2006 (UTC)
thread_title:  proof of existence 

message: The intro says:
:For gases and certain molecular liquids and solids (such as water and sugar), molecules are the smallest division of matter which retains chemical properties; however, there are also many solids and liquids which are made of atoms, but do not contain discrete molecules (such as salts, rocks, and liquid and solid metals).
I see no discussion later about how metals are not molecules. There is mention that single atoms CAN be considered molecules. I suppose there is some thought regarding crystals here, but "rocks" seems unneeded also --JimWae 17:00, 1 October 2006 (UTC)
replies: text: Single atoms are considered molecules only if there's a lot of space between them, as in gasses. I'm not sure we need any additional reasons why metals are not molecules. Metals are made of crystals and if you accept that crystals are not molecules, you're already there. Melted metals are obvious atoms sliding over each other-- there may be globs or more than one atom at some temperatures, but not orderly numbers of globs in metals, such as the 3-atom globs in liquid water. Thus, no  "molecules" as we know them.  As for the mention of "rocks," it's needed.  The earth is made of rock with a metal core. Thus, most of what you're standing on is NOT made of molecules, or a molecular material in the same way that (say) sugar or ice are. That's worth special emphasis. Molecules are common on Earth, but most of the Earth is not made in a molecular pattern. SBHarris 18:43, 1 October 2006 (UTC)
thread_title:  Metals not molecules?