Talk:Physics

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[edit] History merge

I've added tags proposing that Physics#History be merged into History of Physics and replaced with a much shorter summary. The current history section dominates the article, accounting for probably more than half the text. Summarizing the history briefly would allow room to expand the sections on Theories and Research, which I think should constitute the bulk of this article. Gnixon 16:16, 16 July 2007 (UTC)

I'm going to be (very) WP:BOLD and just cut the history section from this article. I've read through it along with History of Physics and I didn't see any information here that wasn't there. It might be worth having a short "History" section in this article that summarizes the other one, but the current section is nothing like a summary. Gnixon 22:58, 16 July 2007 (UTC)

[edit] Changes

I've recently made a number of WP:BOLD changes to the article. My goal was to rearrange existing content into the skeleton of an article with expanded coverage. To make room for more discussions of theory and content, I made the following cuts:

  • Moved content in "History" to History of Physics. This cut the total size of the article in half, since History previously dominated.
  • Moved table of theories to Physics/Theories and linked to it. Table was too large to convey information at a glance, and it broke up the flow of prose.
  • Moved table of fields to Physics/Subfields and linked to it. Same reason as above.

I also moved each of the theories and subfields into their own subsections. Each needs to be greatly expanded to justify its own subsection, but it seems entirely appropriate to do so. In addition to the above major changes, I also added a couple of images. Please help to expand the new subsections, or comment here if you think I'm a dunce for doing this. Cheers, Gnixon 00:38, 17 July 2007 (UTC).

Krea has made some changes which were from the development article. After adding this page to my watchlist, I was pleasantly surprised to see changes for the good in this article. Good work, Gnixon. Perhaps we might all work on this article together. --Ancheta Wis 11:17, 13 September 2007 (UTC)

[edit] More bold edits

About a week after proposing and making changes above, which left the article in sort of a skeleton form, only one or two of the sections had been expanded by others (my thanks to those who wrote something). Because of that, I've gone ahead and copied info into each section from the leads of relevant main articles. Unfortunately, most of those articles aren't very good, so the writing copied here is mediocre and inconsistent, but at least there's something. I've re-deleted the gigantic, awful History section twice after it was reinserted by people who seemed to think the deletion was simple vandalism. If people disagree with deleting that section, or with the other major changes I've made, please comment here so we can discuss them further. I'm not trying to WP:OWN this article, but there's been very little life on this page over the past few months. Gnixon 03:34, 22 July 2007 (UTC)

Since the text copied from other articles isn't that great, I'd encourage knowledgeable editors to try rewriting a section from scratch. If incremental improvements are possible, that's great, too, but please try to avoid adding unnecessary detail into this very broad article. Gnixon 03:34, 22 July 2007 (UTC)

I think you hit the nail on the head earlier when you said that having the Talk:Physics/wip pages puts people off from editing here (or there). You might persuade more people to contribute if you could come to a joint position with User:Krea and User:Ancheta Wis, who seem to be the only survivors of the wip wars. We now have two overview-level Physics articles with almost nothing in common; in particular, the "visible" Physics ignores the global structure that was thought out with some care in the wip debates. In fact, it seems to correspond just to two of the sections in Talk:Physics/wip/development_article (i.e. "Principles & concepts" and "Current Research"). It would be great if you all could produce an agreed merge of the two overviews, with creation of spin-off pages as appropriate, and finally delete the development article.
Sure, I'll try to talk with them. I remember being concerned at some point that the wip pages might be spending a lot of space waxing philosophical about the nature of physics, but when I've glanced at them more recently, there seems to be a good bit of useful material there. Gnixon 20:08, 22 July 2007 (UTC)
FWIW, here are some questions/suggestions based on a cursory reading:
  • Do you have some sort of objection to use of WP:SUMMARY, specifically to {{main}} tags?
I intended to put in a bunch of "main" tags, but keep forgetting. I'll try to do that soon. Gnixon 20:07, 22 July 2007 (UTC)
  • Physics should certainly include sections discussing definition and history. As usual they should summarise longer discussions on pages devoted to these topics (since both are large topics in themselves). The development article contains a lot of material that could be used for such pages, but I agree that, as it stands, it covers these topics in much too much depth for an overview. (I havn't checked to see whether the history content is already duplicated at History of Physics).
I agree that this article should have a history section, but as you say, it's a big subject, and the History of Physics page doesn't seem to have a good lead. I was loosely planning to try and write a summary of the history at some point, but it's a fairly big job to get it right, and I thought it would be best to just let that paragraph in the lead serve until someone comes up with something better. Gnixon 20:07, 22 July 2007 (UTC)
  • Thanks to anon 68.. for putting in a mention of statistical physics; this now needs to be fleshed out a bit in the section that now includes this in its title.
Should we describe stat mech as a subject distinct from thermo instead of as a part of it? I'm not aware of any applications of stat mech to areas outside of thermo. Admittedly, there isn't nearly enough coverage of stat mech in the thermo section, but I'm not sure it deserves its own section. Gnixon 20:07, 22 July 2007 (UTC)
  • Richard Feynman identified the most important discovery of physics as "everything is made of atoms". Like many universities, mine includes a core physics course called "Gases, liquids and solids" (sometimes called "Properties of matter") which outlines the implication of the atomic theory of matter for...well, everything. I think this deserves a place among your core principles.
Good point. I tried to say something about continuum mechanics under "classical mechanics," but there should certainly be more stuff. I've never heard of a (U.S.) university with a course like the one you describe, but it seems like a good idea. Where would you suggest trying to work it in? Gnixon 20:07, 22 July 2007 (UTC)
  • Why is some of the material you have spun off (e.g. the tables) on sub-pages of Physics rather than top-level pages?
It was a tough decision to remove those tables from the main article, since obviously a lot of work went into making them, but I thought their large size and level of detail made them disrupt the article without providing much at-a-glance info. The reason I put them into subpages instead of the main namespace was just that I didn't know if they were appropriate as actual articles. If someone wants to put them in the main namespace, and that conforms with policies and practices, etc., I'm totally fine with it. Of the three thing I put in subpages, I think Physics/Further reading is the most useful. Gnixon 20:07, 22 July 2007 (UTC)
  • IMHO, one strategic mistake of the wip discussion was to focus on the most controversial stuff first, especially the lede. It seems to me that a good strategy is to (i) decide on the overall structure of the article (done rather carefully at Talk:Physics/wip already) (ii) fill in the sections starting with the least controversial, preferably on the visible Physics page to allow normal wiki process to help (iii) spin off any sections which threaten to grow too long, e.g. due to a controversy, to specialised pages (keeping a summary, of course) (iv) the lede then practically writes itself since it is supposed to be a concise summary of the rest of the article.
I agree. The lead right now isn't really a summary of the article, but I hope it will become one eventually. I've been putting off trying until a decent History section is available and the rest of the article settles into equilibrium. If anyone wants to try writing a good lead, I'd welcome it, but I'm quite concerned about letting the lead go off into long philosophical diversions about the nature of physics. Gnixon 20:07, 22 July 2007 (UTC)
  • Also IMHO, as a physicist I find the discussion of what "physics" really means quite interesting, except for the "really" since obviously it means different things to different people. Maybe I'm naive, but I would be surprised in this case if people were so dogmatic that you would get Intelligent Design-style edit wars over each word in the main article summary, or revert wars in the page were the different POVs were described in depth. A nice page could come out of the discussion of the various philosophical, sociological, and practical ways the term is used. Nevertheless, I concur with practically everybody that the bulk of the Physics page should describe the academic discipline as it currently exists.
I agree it would be interesting to have a section for such issues, but I'm pretty worried that it could get out of control. Lots of editors who are drawn to Physics seem to be wrestling with the question of "what is physics," or "what is quantum," etc. There are too many big, interesting questions for me to easily write a concise, useful summary section, but if someone can come up with one that won't be vulnerable to exponential growth, I'd be glad to see it. Gnixon 20:08, 22 July 2007 (UTC)
  • It would be nice to see the structure of the article reflect the fact that the theory/experiment distinction is essentially orthogonal to the division into sub-fields. For instance, the discussion of theory vs experiment could be part of the (currently non-existant) definition section.
Agreed. I just didn't know where to put it for now. Gnixon 20:08, 22 July 2007 (UTC)
PaddyLeahy 17:35, 22 July 2007 (UTC)
Thanks very much for your insightful comments, Paddy. I hope you don't mind that I've inserted responses. Gnixon 20:07, 22 July 2007 (UTC)

[edit] Why I switched the Relativity and Quantum Mechanics sections

I have put the relativity section just before the quantum mechanics section, instead of just after it. My main reason for doing that is that the quantum mechanics section refers to relativity but not vice versa. Second, there is a widespread opinion that relativity represents less of a break with classical mechanics than does quantum mechanics. Third, relativity was largely complete by 1915, when quantum mechanics was still in its early stages. Cardamon 00:33, 3 August 2007 (UTC)

I think those are all good reasons, and I like the move. Gnixon 04:27, 3 August 2007 (UTC)
I also agree (FWIW) Amit 18:48, 6 August 2007 (UTC)

[edit] Not Featured yet?!

I surprised this article has not been featured yet. Let's fix it up, folks! Amit 18:49, 6 August 2007 (UTC)

I'd say it still has a way to go before it's ready to be featured. Maybe now would be a good time for a peer review, in order to get suggestions for improving things. I'm a little too busy in the real world to participate much right now, but it would be great if someone else could try to drum up some activity. Gnixon 14:56, 15 August 2007 (UTC)
I'll get on with it as soon as I get some time off from work. I'm supposed to be a wikibreak right now :-/ Amit@Talk 07:57, 1 September 2007 (UTC)

[edit] Lead section review

There's been a lot of work put into the lead section at the development page, and it hopefully also incorporates some elements from the current lead section: thus, I will now move it to the main article for some exposure. This is by no means the final product, and feel free to modify it as you see fit, but please help the article review process by also putting the reasoning for your changes at the wip page. Krea 02:28, 13 September 2007 (UTC)

If anyone can help with the translation of the word phusis, or whatever the appropriate progenitor word was, that would be helpful. Thank you. Krea 02:57, 13 September 2007 (UTC)

added link to Physis (φύσις) --Ancheta Wis 03:42, 13 September 2007 (UTC)

[edit] Why a previous sentence was not so good

This sentence:

Generally seen as an important subject, advances in physics often translate to the technological sector, and sometimes resonate with the other sciences, and even mathematics and philosophy.

had a couple of problems. It seems to say that advances in physics are generally seen as an important subject, although one would expect it to say that physics is an important subject. Also, in physics, translate and resonate can be verbs describing motion so, at least to my ears, the sentence comes off as an unintentional pun. I find myself wondering if there are subjects with which advances in physics occasionally rotate or vibrate. I did a minimal rewrite of the sentence. Cardamon 07:17, 14 September 2007 (UTC)

Good point and good point! I've made the changes directly to the referential copy since they make the sentence much clearer and don't involve any major changes. Krea 14:53, 14 September 2007 (UTC)

[edit] Previous Lead Section

Let me note here that El C made a revert to the old lead section and mentioned that he thought it was better. Firstly, please refrain from reverting back to the old lead without more discussion, especially as the new lead section is only here for general review: I did not delete the old one.

I wont go into the reasons why I think the new lead supersedes the old one here unless anyone explicitly brings it up, but I would note that this issue is far from resolved amongst a few editors, and I encourage people to discuss their objections. Thank you. Krea 15:38, 14 September 2007 (UTC)

[edit] Comments

I won't have much time to work on the article in the near future, but I'd like to make a couple comments about recent changes. I'll sign each paragraph here to help with threading. Gnixon 06:11, 17 September 2007 (UTC)

First, I have to admit I'm not a big fan of the new lead. My main gripe is that it waxes too philosophical about the nature of physics and its importance. It's better, I think, to lay out facts about the topic simply. The new lead is not a summary of the article, as WP:LEAD indicates it should be. The old lead wasn't perfect, particularly on the point of summarizing the article, but I personally think we should revert to it until the new one improves some more. Gnixon 06:11, 17 September 2007 (UTC)

Second, the new section on applied physics contains useful information, but the presentation is horrible. Articles should use bulleted lists only sparingly (as a guideline somewhere indicates), but that section has a list of probably 30 or more topics that are somehow related to physics. Until the list can be reformatted into readable prose, I think it should be removed. Gnixon 06:11, 17 September 2007 (UTC)

Finally, I'm glad you guys from the "work in progress" page are back to working on the main article. I haven't looked at those pages recently, but I look forward to seeing what you've come up with. One request: before you make big changes like replacing the lead, please post here (with a copy of the text) to get comments from those of us who haven't been following along at the WIP pages. Gnixon 06:11, 17 September 2007 (UTC)

Gnixon, thank you for your response to the contributions; I am concerned about the dropping of the History section. Joke137 in fact suggested that the History Section be the 2nd after the lead. For philosophical reasons, this is sound. One of the influences in Kuhn's Structure of Scientific Revolutions, Ludwik Fleck, notes that it is impossible to view any developing subject without also noting its history. Otherwise, we are left with an article which is fundamentally incoherent.
As you note, there is a problem with the bulleted lists in the Applications section. I simply added explanatory text to elements of the table which formerly inhabited the article, and have no problem simply dropping it. However, that leaves out topics which could lead to further evolution of the article. For example, just as 'biophysics' is now recognized as a seminal field, there is a so-called 'econophysics' field of physics which could be seminal. There are editors of Wikipedia who got their employment in this, after getting their Ph.D.'s in more traditional fields of physics; there is a 'financial engineering' major at MIT now, etc. How could this have happened? It simply turns out that the flexibility of mind needed in physics has been finally recognized to be a 'door opener' to employment. What might this have to do with physics? Well, 'open-mindedness' is a well-known attribute for success in the field.
I have no problem dropping the bulleted items, if the community of editors agree. So be it.
The new lead is from the development article, which was intended to replace this one, eventually. Now that this article is improved, changes are not quite so urgent, I suppose. But the new lead sets the stage for items in the development article. That brings us to the question of organization of this page, upon which consensus was reached in the development article. The subject is thousands of years old, and yet reaches into the future as far as the mind's eye can go. That is one reason for Krea's stately lead.
Interested readers can view the current state of the development page here. Krea considered bringing its entire content to the talk page here, which might have forestalled your concerns. Yet that could also have introduced issues which might be avoided by simply viewing the linked page.
--Ancheta Wis 09:16, 17 September 2007 (UTC)
Regarding "econophysics", "biophysics", etc., I agree they deserve a mention. It would be great to add a small subsection to "Fields" entitled "Interdisciplinary Research" or something like that. The fact that the WIP version was intended to replace the article does not necessarily mean that it deserves to do so. I'm not ripping on the WIP stuff, but if we're going to bring in material from it, let's do so bit-by-bit to address specific weaknesses of the current article. The current article is at least decent, so let's go with evolution, not revolution. Remember, even after we recognize that physics is a grand subject, there's a lot of work left to do in order to achieve an article that reflects its grandness. Best not to aim too high at first, or we'll be left with over-broad generalities with little concrete content; I know that from personal experience. Gnixon 15:47, 20 September 2007 (UTC)
Just a quick comment about the history section: I am also very concerned that it has been dropped completely. What we need is for somebody to make a summary of the history of the subject that mentions the major aspects, and glosses over the finer details rather than just cut a chunk of the main history article out, or discard it completely.
Now, about the lead section, I did try (to an extent) to make a brief summary of the article: it mentions it's history, influence, and mentions that it is subdivided into major subfields. I didn't go into too much detail (especially on the last point about it's subdivision) since it would make the lead too long. Also, I'm not sure I prefer mentioning specific areas like QM and GR in the lead since physics, as a whole, is much more than two about two collections of theorems. I think physics is too broad a topic for one to adhere to the guidelines on summarization too strictly. In fact, I tried to do this, and the lead ended up horrendously long. I do agree and think that maybe he influence bit of the lead is a bit too long though.
About it being too philosophical about the nature of the subject, I personally don't see it; but then again, I need your, and other editors, help in order to show me what bits you don't like. The problem I have with the old lead (and I've been moaning about this for a very long time!) is that it was simply incorrect (at least, to me). I've argued before that if one wishes to put a definition of the subject in the lead, to define it as "the study of energy, space, time" etc. was technically incorrect since no serious definition of the subject ever defined it dependent on ideas developed within it. In the course of discussion, some people have taken issue with this, but plenty of textbooks (for a start) support my position. One can, quite appropriately, simply request its removal based on it being too philosophical (as opposed to it being incorrect) but I think that would be a mistake. Quite frankly, it's not that philosophical (and you'd hate to see what I'd put in there if it was left to my own devices!), but again, I need your input and to help me find a solution acceptable to everyone: more specific criticism would be nice.
Finally, about moving the lead to the article, I said before that there was nothing more that I wanted to add and I needed others to help me improve it further: I moved it to the article for this purpose instead of this talk page since exposure to it in these talk pages can be quite low actually (especially at this point in time when general activity seems to be low). I've seen this before since I did move a previous version of the lead to these talk pages and received precious little comment. We've been arguing about the lead for quite some time now, and quite frankly, I think we're at the stage now where we need to finalize it and move on. What we need is a good definition of the subject, and a paragraph or two that summarizes the rest of the article; as long as the lead has these, and there is nothing incorrect, I want to avoid bickering about details as much as possible. Krea 20:28, 17 September 2007 (UTC)
I guess what I liked about the old lead was that it was pretty concise and that it had a nice little summary of the history of the field. I was never too thrilled with its definition of physics, but I couldn't think of one I liked better. There's a recurring problem with this page: since "physics" is such a broad subject, subsections of the article (particularly "history" and the lead) tend to grow much too long, losing their focus. The very long history section from awhile back was a good example of this problem; bringing it back in much, much shorter form would be great. I think the current lead and the current astronomy section suffer from the growth problem, too. For the lead, I'd like to (a) find a simple, concise definition of "physics", (b) use a brief exposition of its development to clarify what "physics" means (i.e., bring back that part of the old lead), and (c) summarize the sections of the article, much as it does now. I would cut everything else. Gnixon 03:10, 18 September 2007 (UTC)
Thanks, Krea, for addressing my above comments. More are below. I don't mean to "bicker about details", but it's also not like we're going to write one perfect lead and move on; the lead, like everything else in the article, will continue to improve over time. Let's continue making small, gradual improvements to the lead as well as the rest of the article. Gnixon 15:47, 20 September 2007 (UTC)

[edit] fields of physics

There is a section currently called fields which I propose to rename fields of physics, if no one objects in the next several days. My problem is that the bare word field is ambiguous in a physics article, as field has a defined meaning which conflicts with its use as a header. --Ancheta Wis 10:31, 18 September 2007 (UTC)

Good point, but "fields of physics" is still vague, and it's redundant with the title of the article. How about "Research Fields" or "Fields of Research". Gnixon 14:46, 20 September 2007 (UTC)

[edit] interpolation into Newton's quotations

For annotating Newton's quotes, it is possible to interpolate footnotes directly, thanks to the wiki technology. Might this be acceptable? It feels strange to do so, because it may interfere with the readings directly from Newton's mind, as it were. Might that be alright? --Ancheta Wis 11:29, 18 September 2007 (UTC)

For example, Feynman Vol. 1 chapter 22 directly explains part of Newton's 3rd quote. I can use a wiki link or interpolate a footnote, or I could just talk about it outside the quote, so as not to disturb it. Which might be preferable? --Ancheta Wis 11:36, 18 September 2007 (UTC)

After waiting, I propose to interpolate the Feynman note as a footnote within the 3rd quote. --Ancheta Wis 23:50, 19 September 2007 (UTC)
I don't think it makes sense to have a History section that consists almost entirely of two long Newton quotes along with a few vague statements about the development of science and physics' claim to be "the most fundamental science". This article is starting to look less like "Physics" and more like "The role of Physics in the Philosophy of Science." Gnixon 14:43, 20 September 2007 (UTC)

[edit] physical approximations

The history section implicitly contains Newton's physical approximations. Looking back on this, which seems natural because of my training in physics, Newton's approach to these physical approximations is the subject of academic research to this day. There does not seem to be enough material in the encyclopedia about this. Do any editors have any suggestions? --Ancheta Wis 10:02, 20 September 2007 (UTC)

Can you be more specific about which approximations you mean? The link is to a book about Einstein's formative years. (!??) The level of detail you're discussing seems more appropriate for a sub-article. Gnixon 14:49, 20 September 2007 (UTC)

[edit] Some comments

Ancheta, Krea. I'm really glad you guys are back to working on the article directly, but it would have been nice if, before making sweeping changes, you'd post the new text on this page for pre-discussion. I know much of the content you've brought in exists at the WIP pages, but not everyone looks at those.

In my opinion, there are a number of problems with the new material, and I think the previous versions were better---my first instinct is to revert and work on proposed new text here. Instead, in the interest of avoiding edit warring (which I don't have time for, anyway), here are some comments: (Gnixon 15:30, 20 September 2007 (UTC))

  • Phrases like "in everyday terms", "the world around us", "Physics is generally seen as an important subject" are too informal. Generally, the lead could could be phrased in more formal language without becoming inaccessible to the novice. Gnixon 15:30, 20 September 2007 (UTC)
  • I like the structure of the new lead, particularly how it is based on the layout of the article. The first paragraph needs more work, though. For example, pronunciation and etymology should be give parenthetically at the very top. We should work on the definition. How do dictionaries define phsyics? Watch the qualifiers---"such as" and "for example" are redundant; better to avoid them when possible, anyway. "It is the general analysis of nature, conducted to understand how the world around us behaves" tells me very little about what is "physics"; it applies equally well to "science." It's clearly difficult to define physics without being circular: "Physics is the study of the physical world." Still, we can do better. We should be guided by WP:LEAD. Gnixon 15:30, 20 September 2007 (UTC)
  • Basing the entire history section on two Newton quotes is a mistake. Newton was an important figure, but so were several others, and we can't afford to give so much detail in the top-level article. The info is good, though, and someone should check that it's included in the Newton article. It's unfortunate that History of Physics is too crappy to offer much guidance. If we figure out a good History section, it'd be great to use that as an outline for modifying History of Physics. Maybe we should cut "History" and try to put together a version on this talk page. Gnixon 15:30, 20 September 2007 (UTC)
  • "Applications and Influence" should be moved to a subsection of "Fields" as "Applied Physics." Also, the language is too vague. We need to give specific examples of the major areas and applications of Applied Physics. Too informal are phrases like "had to be discovered before they could be used; today they can be taught to schoolchildren", "what do we know and when do we know it....", "physics reasoning can handle items which normally would be mired in conundrum and uncertainty." (I assume the "thus happiness..." line was just added by some pseudo-vandal passerby; it should obviously be cut.) The section seems to be trying too hard to make very general statements; for example, little content is added by "there are many fields of physics which have strong applied branches," especially when it stands alone, without any supporting examples. The 2nd-to-last sentence of the first paragraph has a grammatical error. Gnixon 15:30, 20 September 2007 (UTC)

These new blocks of text are well-motivated, but they need a lot of work. Gnixon 15:30, 20 September 2007 (UTC)

One of the problems of the development article is that it stayed on the talk page too long. It motivates editors when they see text on the article page. So I propose leaving the text on the article page, if only as an irritant, and copying sections to the talk page to work toward consensus. That, I imagine, was your motivation for the alterations to the history section, after all.
One of the convenient features of physics is that it has a very long half-life. Thus we can still study equations that are centuries old but which are still vital. So one of the features of the 'History' is that it is still alive. In fact, that is a marker of good physics.
I am serious about the 'happiness'. Jeremy Bentham's utilitarianism was about happiness, even if it doesn't play very well to American ears. Anyone who has used a good digital camera, or a decent car, knows what I mean. They are utilitarian, but a good engineer designed and built them. That could only have come from a decent physics education.
But if we consider the physics of Newton, etc (everything in the 'core theories'), they are history, and at the same time, not obsolete. This is hardly the case in any other field of knowledge. Please let me know if you know other examples in other branches of knowledge.
So if we work over sections such as History or Applications, I propose deconstructing specific sentences, and replacing them one sentence at a time in an evolutionary scheme, as you suggested above.
That said, it occurs to me that History and Core theories might be combined as examples of 'vademecum physics' (meaning from the handbook). But the bald statement of say, Newton's dynamical equations, leaves out a lot of subtleties that the founders considered, and restated, and which live on without alteration. That kind of perfection took centuries, and I would like to have that conveyed in the article. So the 3rd quote of Newton would be a nice precis of mechanics, in my opinion, for a History section. I took care in the footnotes of the history section 3rd quote, to show how the motion of the planets can now be simulated by high school kids on their programmable calculators. That is real progress in education, in my opinion, which is what I meant by "had to be discovered before they could be used; today they can be taught to schoolchildren". Those word may have been too informal, and I welcome your critique. --Ancheta Wis 01:32, 21 September 2007 (UTC)
"Happiness" is a strange word to use in a physics article; I'm going to have a hard time coming around to that. I'm okay with going sentence-by-sentence through parts of the article that are already decent. For example, I think the lead is decent enough for that process. On the other hand, I don't think the History section has enough value right now to try evolving from it. We would do better to start with an outline, and to remember to stay concise when we start writing paragraphs. Gnixon 04:09, 21 September 2007 (UTC)
My point is that all our changes should be small improvements, with emphasis on both "small" and "improvement". An exception would be a comprehensive, yet very concise, History section, if and when that's available (talk page first!). I see the argument for sticking something new and experimental in the article. That's fine as long as it (1) has some minimum level of quality (the current History fails there; likewise, I never come up with something worth inserting), and (2) doesn't delete useful content (replacing the previous lead may have done so). Gnixon 04:09, 21 September 2007 (UTC)
I think we can evolve the current lead, and I think the Applications section can be evolved as an Applied Physics subsection, as long as neither of those sections are abandoned as-is. That should be plenty of work to keep us busy and justify deleting History for now, right? Let me be totally clear that I think a great future project would be to develop a decent, concise (!!) History section; I'm just afraid that if we slap something together now, it will detract from the article, not add to it. Finally, I've said it before, and I'll say it again, please, please, please resist allowing philosophy to creep into the article---the subject is broad enough already. Gnixon 04:09, 21 September 2007 (UTC)
As I mentioned on your talk page, sorry if I'm coming off as too critical. I'm glad you and Krea are working on this, and I hope it brings even more attention to the article. Sorry I haven't had time to contribute more constructively. Gnixon 04:09, 21 September 2007 (UTC)

[edit] Newton quote 1

At the risk of recreating the dynamic of the development talk page, I present some annotation for Newton's quote below.

The definitions in Principia, which are not listed here, are part of the philosophy. But here philosophy refers to natural philosophy or what we refer to as 'physics'. The keyword 'principle' does not have a modern counterpart except for the term 'fundamental interaction'. These can be viewed as Newton's demarcation between what is physics, and what is mathematics.


Newton's dynamical equations. See, for example, Sander Bais, The Equations: Icons of Knowledge ISBN 0-674-01967-9 p.23
Newton's dynamical equations. See, for example, Sander Bais, The Equations: Icons of Knowledge ISBN 0-674-01967-9 p.23
  • "I have presented principles of philosophy that are not, however, philosophical but strictly mathematical -- that is, those on which the study of philosophy can be based. These principles are the laws and conditions of motions and of forces, which especially relate to philosophy."[1] —Isaac Newton, Philosophiae Naturalis Principia Mathematica

Krea, it occurs to me that this quote might be data for the definition effort. Perhaps part of the difficulty in definition (which I suggest that we skate around right now) exists because we (our contemporary age) are too close to the problem. It may be easier if we just wait for more scholarship about the situation. But what will physics be like when we have gained enough perspective, enough distance from the problem of defining physics? It may be a long time from now. --Ancheta Wis 03:53, 21 September 2007 (UTC)

Too close to the problem? Physics has been pretty well-defined for centuries, or at least generations. Here is Merriam-Webster's definition:
 Pronunciation: 'fi-ziks
 Function: noun plural but singular or plural in construction
 Etymology: Latin physica, plural, natural science, from Greek physika, from neuter plural of physikos of nature, from physis growth, nature, from phyein to bring forth -- more at BE
 1 : a science that deals with matter and energy and their interactions
 2 a : the physical processes and phenomena of a particular system b : the physical properties and composition of something
Here is Dictionary.com:
 phys·ics      /ˈfɪzɪks/ Pronunciation Key - Show Spelled Pronunciation[fiz-iks] Pronunciation Key - Show IPA Pronunciation
 –noun (used with a singular verb)
 the science that deals with matter, energy, motion, and force.
That should pretty much settle the first paragraph of the lead. Let's move on. As for the boundaries between physics and philosophy (or physics and math, or physics and engineering, physics and chemistry, etc.), that subject is much too messy to deal with in this article for more than one short sentence. The bit from the previous lead about "physics emerged as a science distinct from natural philosophy" handled the issue quite well, and quite sufficiently. Gnixon 04:18, 21 September 2007 (UTC)
A dictionary definition can be an inadequate characterization for some important topics. For example, the article truth has taken several years to get beyond the common answer; scores of editors have contributed to it. They started with the dictionary definition and proceeded to demolish it in the article on truth. Physics deserves no less. We don't have to start with a skimpy answer in the lead. It can be built up in stages and we have years to do it. Right now, we observe the spectacle of an definition akin to the four humors or Aristotle's four causes. But Newton's quote, coupled with his dynamical equations, is still applicable, even to relativity. So it's still right. To borrow a software analogy, the words of the dictionary definition are not strongly typed but are more akin to weakly typed or untyped. When matter and energy occur in the same series of words you know something is wrong. --Ancheta Wis 15:32, 23 September 2007 (UTC)

[edit] What's up with the History section?

Shouldn't the history of physics include more than Newton? Rracecarr 13:47, 21 September 2007 (UTC) Ok, the section has just been deleted by GNixon. Withdraw my comment. Rracecarr 15:02, 21 September 2007 (UTC)

Since I don't seem to be alone here, I went ahead and cut it. Here is the excised content, for reference or rework. I recommend not trying to put in History until someone figures out at least a comprehensive, concise skeleton of a section. Gnixon 15:04, 21 September 2007 (UTC)
Main article: History of physics
Further information: Timeline of classical mechanics , and other physics timelines

The emergence of physics as a science distinct from natural philosophy began with the scientific revolution of the 16th and 17th centuries, and continued through the dawn of modern physics in the early 20th century. Although physics is immense, it is still possible to glimpse it all from the influence of one physicist: Isaac Newton (1643-1727). Newton's work is an exemplar of a core theory of physics: mechanics.

Newton's dynamical equations. See, for example, Sander Bais, The Equations: Icons of Knowledge ISBN 0-674-01967-9 p.23
Newton's dynamical equations. See, for example, Sander Bais, The Equations: Icons of Knowledge ISBN 0-674-01967-9 p.23
  • "I have presented principles of philosophy that are not, however, philosophical but strictly mathematical -- that is, those on which the study of philosophy can be based. These principles are the laws and conditions of motions and of forces, which especially relate to philosophy."[2] —Isaac Newton, Philosophiae Naturalis Principia Mathematica

From a few equations, Newton was able to posit a System of the World:

  • "Seeing ... the variety of Motion which we find in the World is always decreasing, there is a necessity of conserving it and recruiting it by active Principles, such as are the case of Gravity, by which Planets and Comets keep their Motions in their Orbs, and Bodies acquire great motion in falling; and the cause of Fermentation, by which the Heart and Blood of Animals are kept in perpetual Motion and Heat; the inward parts of the Earth are constantly warm'd and in some places grow very hot; Bodies burn and shine, Mountains take fire, the Caverns of the Earth are blown up, and the Sun continues violently hot and lucid, and warms all things by his Light. For we meet with very little Motion in the World, besides what is owing to these active Principles"[3] —Isaac Newton, Opticks

But the science did not spring fully-formed from Newton. He had to discover some interrelations based on previous theory, experiment, and observation[4]:

"[I] compared the force requisite to keep the Moon in her Orb with the force of gravity at the surface of the earth, and found them answer pretty nearly". --Isaac Newton
"[I] compared the force requisite to keep the Moon in her Orb with the force of gravity at the surface of the earth, and found them answer pretty nearly". --Isaac Newton
  • "In the beginning of the year 1665 I found the Method of approximating series[5] & the Rule for reducing any dignity of any Bionomial into such a series. The same year in May I found the method of Tangents of Gregory and Slusius, and in November had the direct method of fluxions & the next year in January had the Theory of Colours & in May following I had entrance into ye inverse method of fluxions[6]. And the same year I began to think of gravity extending to ye orb of the Moon & (having found out how to estimate the force[7] with wch [a] globe revolving within a sphere presses the surface of the sphere) from Keplers rule of the period times of the Planets being in sesquialterate proportion of their distances from the center of their Orbs, I deduced that the forces wch keep the Planets in their Orbs must [be] reciprocally as the squares of their distances from the centers about wch they revolve; & thereby compared the force requisite to keep the Moon in her Orb with the force of gravity at the surface of the earth, and found them answer pretty nearly.[8] All this was in the two plague years of 1665-1666. For in those days I was in the prime of my age for invention and minded Mathematicks and Philosophy more then at any time since."[9] —Isaac Newton (as quoted in Richard Westfall's biography of Newton, whose mind was Never at Rest)

The subfields of physics were variously created and even unified during this time, as was the study of natural phenomena as positive sciences. Like Newton's reminiscence above, the interconnections between the various fields of study has been shown to be convincing evidence for the validity of science, taken as a whole. Thus sea-floor spreading serves as evidence for plate tectonics, and the cosmic microwave background serves as evidence for the big bang.

However, physics can lay claim to be the fundamental science, from which the others stem.


[edit] Notes

  1. ^ Isaac Newton (1687), The Principia: Mathematical Principles of Natural Philosophy, 3rd edition 1726. Translated by I.B. Cohen and Anne Whitman (1999, Introduction to Book 3, p.793)
  2. ^ Isaac Newton (1687), The Principia: Mathematical Principles of Natural Philosophy, 3rd edition 1726. Translated by I.B. Cohen and Anne Whitman (1999, Introduction to Book 3, p.793)
  3. ^ Isaac Newton (1718), Opticks, (2nd edition 1718, Book 3, Query 31, p.375)
  4. ^ See: scientific method.
  5. ^ See, for example how the Feynman Lectures on Physics Vol. I Ch. 22 Sec. 4, approximates a logarithm by linear interpolation using entries in a table of natural logarithms, to calculate irrational powers and the logarithms of irrational numbers. Note also Feynman's selection of "the most remarkable formula in mathematics" in Ch. 22.
  6. ^ See, for example how the Feynman Lectures on Physics Vol. I Ch. 9 Sec. 6 integrates Newton's dynamical equations from Sec. 5. This is a numerical approximation of what Newton referred to as his inverse method of fluxions. This method was the subject of bitter priority battles with Leibniz.
  7. ^ Galileo (1638), Two New Sciences mentions the 'force' required to move a ball up or down a ramp. See Hawking's section on Galileo, On the Shoulders of Giants, ISBN 0-7624-1348-4 pp. 524-525.
  8. ^ See Richard Westfall's biography of Newton, Never at Rest, for an account of Newton's construction of geometrical proofs, of the heuristic evidence he had found in 1665-6.
  9. ^ Richard Westfall, Never at Rest: A Biography of Isaac Newton (1980, p.143)

[edit] Old lead

I removed the in-line comments from the article, since they made editing quite hard. Here is a copy of the old version of the lead. I'm a fan of the 2nd paragraph (full disclosure: I wrote most of it), and I wonder if it could be incorporated in the current lead, which does a much better job of summarizing the article.

Begin quote:

Physics (Greek: φύσις (phúsis), "nature" and φυσικῆ (phusiké), "knowledge of nature") is the branch of science concerned with discovering and characterizing universal laws that govern matter, energy, space, and time. Discoveries in physics resonate throughout the natural sciences, and physics has been described as the "fundamental science" because other fields such as chemistry and biology investigate systems whose properties depend on the laws of physics.[1]

The emergence of physics as a science distinct from natural philosophy began with the scientific revolution of the 16th and 17th centuries, and continued through the dawn of modern physics in the early 20th century. The field has continued to expand, with a growing body of research leading to discoveries such as the Standard Model of fundamental particles and a detailed history of the universe, along with revolutionary new technologies like nuclear energy and semiconductors. Research today progresses on a vast array of topics, including high-temperature superconductivity, quantum computing, the search for the Higgs boson, and the attempt to develop a theory of quantum gravity. Grounded in observations and experiments and supported by deep, far-reaching theories, physics has made a multitude of contributions to science, technology, and philosophy.

End quote. Gnixon 15:58, 21 September 2007 (UTC)

The new lead also needs a paragraph about the core theories. Gnixon 15:59, 21 September 2007 (UTC)

See comment below, for more considerations. --Ancheta Wis 17:28, 23 September 2007 (UTC)

The old lead is better. Defining physics as the science of matter gives the impression that physics is merely materials science. Definitions of physics given only in terms of matter (or matter and energy) do not provide a complete world picture of physics, as relativity also elucidates the structure of space and time. Energy, matter, space, and time are the fundamental constituents of the universe — physics is the science of the basic principles of the universe (Serway). --Kasparov 23:23, 27 September 2007 (UTC)

Please give a book title, page number, and ISBN for the Serway quote.
I like your characterization of 'fundamental constituents'. 'Basic principle' is reminiscent of Newton's quote 1 above, where he refers to 'mathematical principle' (i.e., equation). But what good is listing 4 items (Energy, matter, space, and time) when relativity shows 2 of the 4 are redundant? --Ancheta Wis 09:22, 28 September 2007 (UTC)

Here is some more material; I quote Sander Bais (2005) The Equations: icons of knowledge ISBN 0-674-01967-9 p.6 :

  • "Mathematics as a language of nature ... These equations are compact statements about the way nature works, expressed in the language of mathematics. ... they have resulted from a critical dialogue between the observation of nature and the intuition and creative thinking of some great minds." --Sander Bais

--Ancheta Wis 09:38, 28 September 2007 (UTC)

[edit] Suggest we move section on thermodynamics and other bulk mechanics next to quantum mechanics

If we were to move the thermodynamics section below relativity then the transition to quantum mechanics would flow more naturally in the article. Blackbody discussions would then lead to Planck's discovery. Matter at low temperatures shows quantum mechanical effects at the macroscopic scale, as well.

As a side-effect, the relationship of Maxwell's equations to relativity would be more apparent, as an example of the covariance of Maxwell's equations under a Lorentz transformation.

So one diagram of interrelationships in the fields of physics would be

Mechanics +-> electromagnetism -->electrical circuitry -> electronics
  |       |
  |       +-> relativity (high speed physics)
  |
  +---> statistical mechanics -> thermodynamics -> mechanical engines
  |  |
  |  |
  |  +-->low temperature physics --> low temperature quantum mechanics
  | 
  +----->particle physics -->Big Bang (high temperature physics)
  |
  +<---->optics (note arrow goes both directions) --> astronomy
  |
  +----->Fluid mechanics -->aerodynamics, hydrodynamics, weather, plasma physics
  |
  +----->Materials science
  |
  +----->Photonics (electro-optics, optical computing elements, etc)
  |
  +----->Hall effect, etc

Note that it's naturally one subject when the subject is dealt with from its history. For example, Rabi's contribution to magnetic resonance would flow naturally to nuclear magnetic resonance, and to atomic clocks and timekeeping. From that, naturally to the GPS (Newton pops up again). From that, to the current work at NIST-JILA on Bose-Einstein condensates --Ancheta Wis 17:05, 23 September 2007 (UTC)

Putting thermo between relativity and quantum wouldn't be unreasonable. The current order (mechanics, E&M, thermo, relativity, quantum) roughly follows the historical developments. I particularly like that the modern, 20th century theories of relativity and quantum are described together after the "classical" theories. Of course, thermo kind of transcends those classifications. Another possibility would be to put thermo last, since it draws from all the other theories. Gnixon 19:55, 24 September 2007 (UTC)
The section has been moved down. Now to connect with Planck. --Ancheta Wis 10:35, 28 September 2007 (UTC)

[edit] Lead Section Comments

Right, a few things have been noted by several people these past few weeks, and so I'll try to address these as best I can. Right now, I'll only comment about the lead and leave the comments about the history section etc. until later. Also, in order to cut down on space, I'll not comment on points (about the lead) that I've agreed with and so you can generally assume this if I haven't mentioned it here.

About whether the new lead should have been put straight into the article, I'm only concerned with getting people talking and discussing the article and not so much with formality. Ancheta has made his opinions known about this, and mine follow those, so I won't repeat them again. But, I'll go along with whatever people decide should be done since I'm not really bothered about how we go about this, just that it gets done.

Concerning the definition itself, from the wip discussions, some editors stated a requirement for a "simple" definition of the subject. Gnixon has also said that the abstract definition of physics elucidated nothing practical about the subject itself. Conversely, Kasparov has now also mentioned the technical inaccuracy of the first line of the new paragraph. As a consequence of these consideration, I tried to include both in the new lead (which is why it contained statements like "in everyday terms": these were there to distinguish the different requirements for the definition). The dictionary definitions all give one way that you can define the subject and it is very useful for giving an impression of what the subject is, and it is also easily comprehensible in most cases. However, they are incorrect. Even the old lead was still technically incorrect. Kasparov, and many others, have mentioned that defining physics as the study of matter, energy, space and time was a good (technical) definition because it was the essence of the subject (since these were the fundamental constituents of that subject). This is not true: fundamental quantities also include things like colour. Also, and this is more pertinent, when we discuss physics at the ideological level, we must include things like the principle of relativity, and the principle of superposition and it would be hard to argue that these are any less important than energy, matter, space and time. Now, the point of all this is that we probably need a section all on its own to discuss these things (the quote that Ancheta gave from Newton was very interesting and I'd love to discuss it, but probably only in this new section). I am willing (and may in fact prefer this now) to go down this road and leave a simplistic definition in the lead section and mention that a proper discussion is made later. If we don't do this, however, I still strongly prefer to include both a simple and a technical definition in the lead. Whatever is decided please don't fault the simple definition for being inaccurate, or the technical one for being too abstract! But feel free to argue whether these should be included at all if you wish.

For the rest of the lead section, Gnixon has stated preference for, at least, parts of the old lead. Since I wrote most (if not all) of the new lead, I naturally prefer the new lead. But, I recognize this as my own personal bias, and, as I stated before, I prefer not to bicker about details. Thus I really don't mind which one (or more accurately, which parts of which lead) we go for. I'm just going to make two comments:

  1. Firstly, Gnixon and I both feel the need for mentioning the scientific method (which is important I think). The way that I went about this was to include some (very brief) context about physics' cultural and historical position with respect to the other sciences and civilization as a whole. I personally prefer to do it this way because it makes the section a bit more interesting quite frankly. But, again, I'm not too bothered about this, especially if anyone feels strongly about it.
  2. I deliberately didn't mention any specific theorems in the lead because quite often it ends up with people revering GM and/or the Quantum theory (and in some respects, it ends up like a popularity contest!). In reflection, perhaps we should mention something, but I would be careful about only including a theorem when it can serve to provide an example for a valid point being made, and endeavouring not to mislead the reader as to the theorem's importance with respect to other ideas in physics (i.e. not mention things like "physics is summed up by GR and the Quantum theory").

So, Gnixon (or anyone else), if you could modify the lead as you see fit, we can then make further comments about perceived strengths/weaknesses. Also, any opinions on whether we should dedicate a section to the definition alone would be welcome (I'm leaning for this to be so, right now); thank you. Krea 17:46, 1 October 2007 (UTC)

Even if dictionaries are "technically incorrect," making that assessment is well beyond the scope of our jobs as Wikipedia editors. Good dictionaries are clearly WP:RS. Using such sources instead of trying to reinvent the wheel with WP:OR is an explicit Wikipedia policy. If dictionaries say physics is the science of matter and its motion, then that's what it is as far as Wikipedia is concerned. Let's just say so and move on. A clarifying sentence or two is fine as long as we don't go out of our way to dumb it down. The best way to explain to a reader what "physics" means is to give examples of what theories, research, topics, concepts, experiments, etc. fall within the subject. It's far too broad and fundamental to attempt an abstract discussion of definitions in the lead. On the other hand, I agree we can't afford to try and list all the big theories, concepts, etc. in the lead. Gnixon 20:04, 4 October 2007 (UTC)
Is there original research? I thought it was fair to assume that definitions from textbooks would be a more appropriate source than dictionaries: a published definition from a physicist rather than an editor's interpretation of such definitions. Because of this, I don't think a dictionary's definitions are equal to these other ones. Is there a problem with this? Krea 03:32, 6 October 2007 (UTC)

[edit] Most compact statement of scientific knowledge

The Feynman lectures on physics I p.1-2 contains a provocative sentence with Feynman's opinion on the most compact statement of scientific knowledge. I appreciate that it was questioned in the revision history, so I included more of the quotation.

Feynman would give pronouncements like this to his students, and their clarity was alway stimulating; for example one of his lectures was on 'the method of solving any equation' which I have never seen in print. --Ancheta Wis 10:24, 4 October 2007 (UTC)

The flavor of his lecture style can be also seen in the first sentence of Feynman's lecture notes on The Theory of Fundamental Processes ISBN 0-8053-2507-7 p.1 'Review of the principles of quantum mechanics': "These lectures will cover all of physics." --Ancheta Wis 10:35, 4 October 2007 (UTC)

[edit] Energy absorption and emission in bulk matter

I propose that we smooth the transition from the statistical mechanics section to the quantum mechanics section with a few sentences about energy absorption in bulk matter: for example, the absorption and subsequent emission of energy in a block of bulk matter. This would unify the treatment of heat in a thermodynamic system, like a gas, with the behavior of a blackbody and the absorption and emission of light. This will lead to Wien's law, and Planck's correction, which leads straight to quantum mechanics. --Ancheta Wis 08:11, 10 October 2007 (UTC)

[edit] Fundamental definition

"Physics is the science of matter[1] and its motion[2][3], as well as space and time[4][5] —the science that deals with concepts such as force, energy, mass, and charge."

Couldn't physics be better described as the science of energy (which is the makeup of matter, motion, mass, charge and force (force can be considered a translation of energy)), space and time?

"As an experimental science, its goal is to understand the natural world.[6][7]"

Shouldn't we say "the universe", let alone the unnatural world as well? —Preceding unsigned comment added by 58.165.121.161 (talk) 09:24, 31 October 2007 (UTC)

I personally have no problem with 'energy' but that lifts up the level of abstraction in the lead sentence, to something like "'energy' is the new water" of Empedocles' Classical elements, which have a checkered history. That is the reason that the lead sentence mentions 'matter and motion' in the same clause. The development article actually spent months on a lead, and you are welcome to look at it there.
I personally have no problem with 'universe' but that would restrict the POV of the article to the cosmos and reduces the role of the microcosm, as in quantum mechanics.
There is a problem with 'unnatural world', because it includes fantasy and other problematic statements of 'knowledge'. When you restrict yourself to statements which do not deal with untrammeled imagination, but which obey the strictures of scientific method, then at least you have a chance of stating a truth. Otherwise, there will be no difference between trash and treasure in the jewel box of natural laws which are commonly called the laws of physics.
Your point is worthwhile and probably deserves a separate article on the difficulty of defining physics in a sentence or paragraph. My personal prejudice would be to list equations of physics, like Sander Bais does, in The Equations: icons of knowledge ISBN 0-674-01967-9. But that won't fly in the encyclopedia. --Ancheta Wis 11:00, 31 October 2007 (UTC)
Note: World Cat has the ISBN entry wrong. Try Library of Congress instead, if you are following the ISBN --Ancheta Wis 14:53, 31 October 2007 (UTC)

Let me just say that I see your point. Firstly I can see how describing physics in one sentece by calling it the "science of energy" can lift the level of abstraction to many. I also appreciate that in existential circumstances such as those that you described, doing so can be confusing and perhaps even incorrect. I now better appreciate the merits of using matter and motion in the same clause. However I believe the first clause should and can define the topic entirely. Anything proceeding should only support this. I believe such a sentence would exceed the merits of the current one, the first clause of which only defines a narrow section of physics. If the fundamental makeup of the universe is energy, space and time, then our challenge here is the express physics as such, while contextualising in such a way as not to lift the level of abstraction.

Moving on, when we say "universe" we can contextualise in such a way that doesn't mislead some into thinking we are narrowing down to astrophysics. Further, don't get me wrong, I wasn't implying we should use the term "unnatural world".

On a side note, I agree entirely that physics is hard to define so concisely. Also, equations are just a way to express things. They can also be expressed with words.

A wild stab at trying to do what I've been talking about is here. If anyone has any other ideas, give it a shot.

"Physics is the study/science of energy, space and time. Energy is the makeup of all entities in the universe apart from space and time. Such entities include matter, mass, charge and motion. Force, another key entity studied in physics, can be considered a translation of energy. As an experimental science, the goal of physics is to understand the universe at all levels of scope." 58.169.193.41 09:21, 3 November 2007 (UTC)

We appear to be on the same wavelength. Thank you. During the definition phase of the wip article, one problem which I encountered was which entities?.
What your proposal appears to be saying is that as the fundamental science, physical laws apply to all entities; that as the earliest physicists observed the stars, and the motion of the planets, and the classical elements, some physicists were able to discover truths. Furthermore, by repeated application of these fundamental truths, the scope of physics has so far been found to apply to all entities, up to the bounds of space and time.
In this way, the existence of the big bang was discovered, and our knowledge that time itself began in that epoch.
In the same way, the knowledge that we ourselves (our physical bodies) came from the stars.
In the same way, that energy is a common denominator by which entities with mass, charge, spin, etc. transform and translate.
In this way, we see how, in the instants after the big bang, the fundamental forces separated and 'froze out' into the asymmetric forms we see today.
Thus, the four rules of reasoning in Newton's program has succeeded, so far. By scientific method, which Newton sketched in the link, it is possible that some other phenomenon will be discovered which will overturn the brief world picture above.
Sorry I have to leave right now, but the proposed definition sketched above appears to be consistent with physics up to General Relativity; the high-energy realm of the big bang (and the forms of matter at high energy) are ... .
--Ancheta Wis 12:22, 3 November 2007 (UTC)

In answer to your first question: "All entities", well perhaps "physical entities" - otherwise the philosophers would trip us up on that one. By all physical entities I mean not just matter, but mass, charge, etc. I understand that entity is a generic concept, but isn't it fact that energy is the makeup of all physical entities? In response to your next passage, yes, this is an very interesting and eloquent way of saying that physics is based on energy and space-time. On a side note instead of "entities WITH mass, charge, spin, etc", why not "such as"? Your last comment interests me. If such a definition is not consistent with the development of General Relativity, then is the current one?...

Anon

My problem with mass as an entity is that mass is an intensive attribute rather than extensive. That is like calling 2 an entity, when 2 is an attribute in my book. As you can see, we are right down to philosophy. But my answer might be one a physicist would give, saying that an integer is not real. So I guess it boils down to 'what is real' and for me, nature is real, true, observable by scientific method, repeatable by scientific method.
When Newton defined mass points as his elements of computation, he derived the motion of the planets, You could argue that the mass points are entities. I agree that points with mass are entities, but that mass serves as adjective to point, which is an undefined term, according to my geometry teacher. So we are back to concepts which must remain undefined, just talked about, but used.
If we were to expand on this, you might say that points were the basis for physical laws from the 1600s to 1900, and that they are the mathematical model for atoms. But when atoms were found to have structure, then we had to change our model to something that is more subtle. Thus the exploration of symmetry and strings in recent times.
The nice thing about scientific method is that definition is not the starting point; instead, a characterization is the fundamental place to start. Characterization can include definition, but also observation and measurement, and information gathering.
--Ancheta Wis 12:39, 13 November 2007 (UTC)

"American Heritage Dictionary - Cite This Source - Share This en·ti·ty (ěn'tĭ-tē) Pronunciation Key n. pl. en·ti·ties

  1. Something that exists as a particular and discrete unit: Persons and corporations are equivalent entities under the law.
  2. The fact of existence; being.
  3. The existence of something considered apart from its properties."

"American Heritage Dictionary - Cite This Source - Share This point (point) Pronunciation Key n. ... Mathematics

  1. A dimensionless geometric object having no properties except location.

... " I'm not sure how authoritative these are, however... Two things:

1. An entity having to be something "real". Now this is getting tricky, because how can we really define what is real, now that we're getting to the philosophical side of things. But lets boil it down even further to what "exists". Does something need to be (a)/(a group of) particles, em-waves, magnetic fields or what have you to "exist". The problem is that we could widen our definition of entities beyond nature that is "real", "true" and "observable", to other things. I think if we opened our minds up a bit, we could see how the spin/orbit of a nucleus/electron respectively (ie. mass, i hope) could be considered an entity, but, again, this is a matter of philosophy
2. Your taking of our idea of a point as an axoim. It is not an axoim (i hope) and any way of pretending it is so is a simplification (I would hope).

Interesting debate though... I guess it can't go any further. 124.177.66.44 (talk) 02:46, 29 January 2008 (UTC)

[edit] QUestion

There is an equation that basically goes like: (normally it is solved for s (distance))

a=2s/t*2

acceleration = (2 times distance) over (time squared)


My question is, in short, where does the 2 come from??? I thought acceleration = velocity / time -is this correct? and if that's correct then a = s/t*2 but where does the 2s come from? BriEnBest 07:39, 13 November 2007 (UTC)

This parabola-shaped lava flow illustrates Galileo's law of falling bodies as well as blackbody radiation -- you can tell the temperature from the color of the blackbody.
This parabola-shaped lava flow illustrates Galileo's law of falling bodies as well as blackbody radiation -- you can tell the temperature from the color of the blackbody.
BriEnBest, see derivative and its inverse operation, the integral. Acceleration is the derivative of velocity; integrating, velocity is the integral of acceleration. That is where the 2 comes from. If s=t*t, then v=2t. In 1638, Galileo gave us his law of falling bodies, which is a square law. That is the reason that the lava in the image is following a parabola.
If we expand the laws of motion which the lava is obeying, we get other beautiful trajectories which are conic sections, as the answers.
--Ancheta Wis 11:49, 13 November 2007 (UTC)
oh yeah, i forgot.. that's an awesome picture btw. thanks :p 67.131.226.195 11:32, 13 November 2007 (UTC)
Good answer, AW (and cool picture!), but remember this page is only for discussing the article. Gnixon (talk) 05:27, 8 January 2008 (UTC)

[edit] Where is the section on teaching physics?

After ten years, doesn't Wikipedia have an article on the teaching of physics, i.e. physics education?

Well, this should be embarassing for the Wikipedia editors. Apparently there is an article on physics education...but the people who wrote it acted as if it had nothing to do with physics! They never came here to collaborate with the physics article editors. Seems a bit odd. And the people who spend time writing about physics, or its various fields, never thought about how to educate people on the subject? Well, I have made a few links that hopefully will correct this.
It is six years going on seven. Wikipedia started Jan 15, 2001. There was a physics article from the beginning.
One might argue that there also ought to be an article on learning physics, which is currently being addressed by the list of basic physics topics and category:fundamental physics concepts, where the goal in the encyclopedia was self-education.
Welcome to wikipedia. Your new perspective will be invaluable and the editors look forward to your additional contributions. You are welcome to get a username, which is handy if you want to upload images, for example.
I personally am a big fan of Louis Bloomfield, How everything works: making physics out of the ordinary ISBN 0-471-74817-X and also Paul G. Hewitt, Conceptual physics ISBN 0-321-05160-2. These books stay pretty much in the classical realm, but the physicists like Brian Greene, Alan Guth, Michio Kushi, Stephen Hawking, etc. have made widely-known efforts to reach the public with the post-Newtonian parts of physics. I wonder if you have thoughts on teaching about the classical realm in the high schools; that way the observations can stay inexpensive.
--Ancheta Wis (talk) 20:58, 17 November 2007 (UTC)
I just had a look at the PER article and was surprised to see that D'Alembert's principle was not mentioned in the section on Newtonian physics. If we look at things from D'Alembert's pov then we look for the forces necessary to reduce everything to statics. This idea works in electromagnetics as well (reduce everything to electrostatics). I learned this trick from Kurt Lehovec, one of the inventors of the integrated circuit; that's how he analyzed the non-volatile RAM in class for us, before there were any; now you can buy them in the drugstore). And if there aren't any forces to make it static, add in a fictitious force to balance it out.
--Ancheta Wis (talk) 23:03, 17 November 2007 (UTC)
I notice that the article section header is Physics education. That is actually of larger scope than Teaching Physics. Do you really mean Education? That could be interpreted as broadly as being the Presidential Science Advisor, currently staffed by a physicist, which raises issues which are currently not addressed in the article. Max Born stated that the physics of the current time will be the philosophy of the future (hence the politics of the farther future). I suggest that the section header be renamed Teaching Physics to skirt the change of scope in the section. --Ancheta Wis (talk) 00:27, 18 November 2007 (UTC)
After having listed some YouTube links to selected physics topics, I am undecided about Applied physics from the article. For example, the atomic bomb is an application which was developed immediately after the discovery of fission at the eve of WWII. But the amazing machines we are using to communicate with each other right now are examples which are just as good. Might an applied section be good to have links for?
I have tried to include links to demonstrate that physics is fun, vital and interesting. --Ancheta Wis (talk) 12:40, 21 November 2007 (UTC)

[edit] Learning physics

Since an (anonymous) editor has noted the omission of teaching physics, I propose a companion section on learning physics. Here, for example, one might note the need for some fundamentals which are necessary to get started, such as building up a store of physics experiences. These would be needed to supplement the laws of motion, etc. One thing might be videos of common phenomena, such as birds flying, balls moving, water dropping, cars starting and stopping, lightning, rain. The use of physics engines for video animation might be an ambitious project, but it would be useful for animating the motion of an airplane, ball, etc. Simple electrical circuits might be appropriate here.

I have moved the links to Talk:List of basic physics topics, that they might be integrated more fully into List of basic physics topics. --Ancheta Wis (talk) 17:54, 23 November 2007 (UTC)
http://en.wikiversity.org/


ThisMunkey (talk) 14:39, 3 March 2008 (UTC)

[edit] disambig?

I seriosuly doubt anyone going to the physics page is looking for the aristotile work1 —Preceding unsigned comment added by 99.247.120.178 (talk) 06:42, 26 December 2007 (UTC)

Here's the problem though. There is no other way that people searching for "Physics" by typing in the URL are going to get to the Aristotle work. Since Aristotle is pretty notable, and the Physics is a pretty notable work, I suggest leaving the disambig. SaveThePoint (talk) 06:45, 26 December 2007 (UTC)
I think you both have good points. Couldn't someone looking for the work by Aristotle find it easily enough from the Aristotle article or by searching for "Physics Aristotle"? Gnixon (talk) 05:22, 8 January 2008 (UTC)
What the Wikipedia guidelines have to say about it? Redundance is not necessarily bad, specially in an information network. My personal impression is that keeping the disambig is a harmless choice. Old Palimpsest (talk) 19:12, 22 February 2008 (UTC)

[edit] Image:Meissner effect.jpg listed for deletion

An image or media file that you uploaded or altered, Image:Meissner effect.jpg, has been listed at Wikipedia:Images and media for deletion. Please see the discussion to see why this is (you may have to search for the title of the image to find its entry), if you are interested in it not being deleted. Thank you. Papa November (talk) 15:31, 28 January 2008 (UTC)

[edit] Definition

The words 'how the natural world works' in the first paragraph suggest too strongly to me that the natural world must have a set of rules or mechanisms. I believe that this is is too restrictive. It also appears to be a misquotation from the given source.Martin Hogbin (talk) 23:38, 4 February 2008 (UTC)

I have reverted back to Krea's formulation. --Ancheta Wis (talk) 23:56, 4 February 2008 (UTC)

Personally, I prefer that formulation. 'Behaves' seems a good word to use.Martin Hogbin (talk) 09:15, 5 February 2008 (UTC)

[edit] "Branches" of Physics

I suggest a reformulation of

Although seen as distinct today, natural philosophy, chemistry, mathematics and biology are all "branches" of physics.

Mathematics is a tool, not a "branch" of Physics, and must definitively be excluded of the list. Physics assumes that natural processes are intelligible through mathematical models. It is therefore unable to found mathematics in the same sense it apparently founds chemistry and biology. Old Palimpsest (talk) 15:16, 22 February 2008 (UTC)

Removed the problem sentence. 'Twas "physics snobbism" at work :-) and unsourced. Vsmith (talk) 15:54, 22 February 2008 (UTC)

Thank you very much for your attention. Concerning snobism, I don't think it is too snobish to mention the indisputable fact that quantum mechanics explains the Periodic Table of chemical elements in every detail. In this sense, it is perfectly legitimate to consider chemistry as a branch of physics. Old Palimpsest (talk) 18:51, 22 February 2008 (UTC)

[edit] Quantum Mechanics - Picture or Illustration

The picture on the quantum mechanics section was very convincing but after a thought, not very convincing at all (as improbable). Could some one add the words "representation" or "image of" and if "image of" include what sort the "imager" was?
Would anyone help me>? What is the name for physics relating to the force of a bullet at high speed compared to a bullet at low speed. IE: a bullet at low speed will push an object but a shot bullet (at high speed) will pierce the same object. What section (or name) is that?
ThisMunkey (talk) 14:37, 3 March 2008 (UTC)

The hydrogen atom illustration shows the calculated probability density of electron orbitals in hydrogen (see Hydrogen atom#Visualizing the hydrogen electron orbitals). Electron orbitals cannot really be imaged, since when you measure an electron position it can only end up being in one place at a time.
As for bullets, you might be interested in ballistics and physics of firearms. — Laura Scudder ☎ 14:58, 3 March 2008 (UTC)
I have seen pistures of quarks where the electron was smashed in an accelerator and the little sparks where seen as evidence of quarks. Maybe it should be noted as an illustration. No, the physics of firearms doesnt make a reference to what Im after. Maybe its some sort of friction but the physics of the impact changes at high speed. Maybe its not researched ? Unlikely.
ThisMunkey (talk) 10:20, 4 March 2008 (UTC)
The same goes for a hammer.
ThisMunkey (talk) 10:22, 4 March 2008 (UTC)
The main issue is: Momentum. I think the picture is fine. Missingdata1 (talk) 18:44, 23 May 2008 (UTC)

[edit] Heavy picture

http://en.wikipedia.org/wiki/Image:CMS_Yep2_descent.gif that is shown under http://en.wikipedia.org/wiki/Physics#High_energy.2Fparticle_physics is a very heavy picture (nearly 4MB) and not really that much important. Isn't it better to change it to a non-animated picture of the particle accelerator instead? --81.227.87.148 (talk) 18:16, 9 March 2008 (UTC)

Agreed, it was far too large for the article, and it was forced to be 300px wide as well, so any user preference would be overridden. I have replaced it with an appropriate small still of an LHC simulation. SFC9394 (talk) 19:13, 9 March 2008 (UTC)

[edit] Definition

Perhaps the best definition of physics is the all-encompassing and simple, yet abstract, definition: "Physics, the most fundamental physical science, describes the basic principles of the universe." (Serway) --Kasparov (talk) 22:51, 13 March 2008 (UTC)

[edit] core theories

i think we should revert to putting a hedding for core theories of physics as branches of physics, be cause thats what they are. Calling thermodynamics, quantum mechanics, etc core theories is incorrect since each of them consists of mnay theories and it just sounds like a bad high school paper. Brnaches of physics is what are the various theories of sections of physics not fields that use more then one if not all the brnaches of physics. Anyways am just floating the ideas around to get some feedback. —Preceding unsigned comment added by 24.36.181.171 (talk) 08:05, 2 April 2008 (UTC)

I think the change from "core theories" to "branches of physics" lost some of the sense of what the article was saying. Each of the fields listed (classical mechanics, electromagnetism, relativity, thermodynamics, and quantum mechanics) is governed by a particular body of theory. There are multiple individual theories within each, but these fit into the overarching framework of theory that defines each field. "Branches of physics" on the other hand are things like nuclear physics, molecular physics, solid-state physics, etc. "Branches" are areas of research in which scientists work. Classical mechanics is not a "branch" of physics. Nobody is studying classical mechanics anymore. It is just something physicists use in doing their work. Similarly, there is little fundamental research going on in electromagnetism or thermodynamics. These are areas of physics that are defined by an essentially-complete body of theory. The areas that remain open are applications of the theories, and development of new bodies of theory (as relativity developed out of classical mechanics and electromagnetism).--Srleffler (talk) 04:41, 9 April 2008 (UTC)
Another way of putting it: classical mechanics, electromagnetism, relativity, thermodynamics, and quantum mechanics are bodies of theory that are used in nearly all branches of physics. They are core bodies of theory that underly pretty much everything else in physics. I understand the complaint that these are not single theories. Perhaps someone can come up with a better name than "core theory".--Srleffler (talk) 02:46, 10 April 2008 (UTC)
There is precedent for denoting them 'core theories': for example, the biophysicist and Howard Hughes Medical Investigator Charles F. Stevens, M.D., Ph.D., has written a condensed summary of The Six Core Theories of Modern Physics MIT Press ISBN 0-262-69188-4 (1995). In Stevens' view, the six core theories are classical mechanics, electromagnetism, quantum mechanics, statistical physics, special relativity, and quantum field theory. And in Stevens' sense, the branches of physics which are areas of current research in physics are denoted 'Modern Physics' just as Srleffler states. --Ancheta Wis (talk) 10:35, 10 April 2008 (UTC)
How about denoting them 'core frameworks'? That leaves room for the current theories in modern physics to roam unfettered, so to speak. --Ancheta Wis (talk) 02:19, 11 April 2008 (UTC)

am on agreement on the issue i reverted back to branches of physics from core theories but now am starting to see this isnt really appropriate either, but something better then core theories is in order i think —Preceding unsigned comment added by Tomasz Prochownik (talk • contribs) 20:51, 15 April 2008 (UTC)

i put fundamental branches of theory in physics, whats everyone think about this?Tomasz Prochownik (talk) 01:44, 21 April 2008 (UTC)

How about "Basic theories"? Gnixon (talk) 19:40, 28 May 2008 (UTC)

I'm concerned that "branches of physics" is a better description for the research fields than it is for mechanics, E&M, etc. Can we discuss this further? Gnixon (talk) 16:35, 4 June 2008 (UTC)

FWIW, I agree with Gnixon, Srleffer and Ancheta Wis: "Core theories" is best ("basic theories" sounds a bit...basic). PaddyLeahy (talk) 17:47, 4 June 2008 (UTC)
I could live with "core," but can you elaborate on the objection to "basic." (Not to make a mountain out of a molehill.) Gnixon (talk) 17:58, 4 June 2008 (UTC)
Well, basically, "basic" is basically alright but, you know, kind of not very specific, the basic trouble is it's a bit naff, :) maybe it's a specifically English naffness I dunno PaddyLeahy (talk) 19:21, 4 June 2008 (UTC)
Poor taste? Meh, "core" is fine with me. Gnixon (talk) 20:29, 4 June 2008 (UTC)

branches doesnt really confuse with fields in physics, since areas of research are called just that fields, what the title needs to adress is the theoretical division upon which physics rests or the divisions that exist between all the different theories, plus this page also lists a section of research fields in physics so i thinkn it provides some clarity.Tomasz Prochownik (talk) 02:25, 9 June 2008 (UTC)

[edit] Diagram: Speed/Size

The diagram is oversimplified. Quantum mechanics may be relativistic (Dirac equation). Field theory has also nonrelativistic formulation. Classical mechanics may be relativistic and non-relativistic. Therefore I would say it's false and misleading. 87.206.101.253 (talk) 19:16, 30 April 2008 (UTC)

According to the way we have it laid out, classical mechanics and relativistic mechanics are distinct. As for QFT, I was under the impression that QFT came out of the need to make QM relativistically covariant.--Loodog (talk) 19:29, 30 April 2008 (UTC)

[edit] Request for mediation at Shor's Algorithm

IBM implemented an alleged quantum computer which ran Shor's factoring algorithm to factor the number 15.

A user had been qualifying quantum computer with simulated quantum computer and qubits with psudo-qubits, etc. I reverted the edits, asking for citations. No reasonable citations were provided and such changes were made again.

I do not know much about NMR quantum computers so I must assume these changes were made in good faith. I am unable to reach an agreement with this user and do not know how to proceed. If anyone knows anything about NMR or wikipedia policy, your assistance would be appreciated. Please see: [1]. Thanks Skippydo (talk) 21:23, 28 May 2008 (UTC)

Skippydo, it's basic quantum mechanics: the simplest case (up or down) (1 or 0) is a mixture of multiple states (1 or 0) at the same time. And it will take an observation to pull out the answer (how much 1 vs how much 0). When a quantum computer is realized (and it already is, because theory says we live in a QM world), the work will be to build devices which pull out the answer.
Don't be buffaloed by the NMR. It is just a technology for getting known states (spin up or spin down). A quantum computer calculates everything all at once, and it will take work to disentangle the results of a quantum computation so that they can be read out like a traditional sequential computer. This point of view comes from R. P. Feynman ===> A quantum mechanical calculation is the same as an observation. --Ancheta Wis (talk) 02:58, 29 May 2008 (UTC)
This discussion should continue at Shor's Algorithm, not here. 128.112.84.21 (talk) 14:16, 29 May 2008 (UTC)