Talk:Physics/wip

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Contents 1 Physics Article Development - Introduction 1.1 The Key Points 1.2 Framework 2 Lead Section 3 Introduction 4 History 5 Branches of Physics 6 Current Research 7 Applications and Influence 8 See Also & External Links 9 Miscellaneous 10 Fringe 11 Admin

[edit] Physics Article Development - Introduction

This page is for discussion related to the development and improvement of the Physics article. As a result of a noticeable decrease in quality of the article it was decided to create a dedicated sub page where the entire contents could be reviewed and improved without the problems of working on a 'live' page which suffers from constant flux. Other editors have suggested that I act as a form of a secretary. The purpose of this is to add a structure to the process, setting up points for discussion, allowing discussion to take place, calling for consensus after an appropriate amount of time, helping to negotiate and reach consensus, then setting up another point for discussion. Editors who want to join this process are more than welcome - the more people we have involved in the process the more valuable the outcome.

The revised plan is for editors to freely edit the development article, and to post anything they want to discuss in this talk page. Once all areas have been discussed, and before the contents are copied across to the main article, a specific amount of time can be set by for A.O.B. to allow past decisions & consensus positions to be reviewed if editors feel strongly about something (and feel it wasn't given fair hearing the first time around - or if the editor wasn't around for the specific discussion the first time around).

Once the final version is completed then it can be copied across to the main article. At that point it can then be freely edited, At this poiand the wiki process will take over on this work. The quality may well decrease again, but at least there will be a consensus version to compare with, and editors can at that point bring discussion on the main talk page as to whether the changes are better than what was decided upon here, or worse. Hopefully the majority of the work done on this project will remain intact, but obviously the final version produced here should not be permanently held in place irrespective of changes made by other editors.

[edit] The Key Points

To ensure that development progresses in an orderly manner there are a few key points that must be kept in mind:

• Consensus is the key rule by which this process lives on. Only through this method will we arrive at a result which is going to stand up to the test and scrutiny of time. Give and take is required by all.

• Editing on any section is permitted, and any possible conflicts about a particular section should be discussion on this talk page and be remedied via the normal wikipedia practice.

• Above and beyond Civility, a friendly and co-operative environment is encouraged. Ultimately we are all here voluntarily, and all just to try and construct a HQ encyclopedia - if folks start getting worked up then we just need to chillout. A negative environment is neither as constructive nor all that nice a place to work as a positive and friendly one. The use of smilies is encouraged. !

Thanks, SFC9394, 23 August 2006 (Minor revisions by Krea 17:03, 5 March 2007 (UTC)).

[edit] Framework

1. Pre-Implementation Discussion, - August 2006

2. Article Structure - Layout & Chapter Focus, - August, September 2006

3. §1 - Definition, Archive 1, Archive 2, Archive 3 - discontinued March 2007

4. General Editing - active

Please use the appropriate section in which to discuss that particular part of the article.

[edit] Lead Section

Continuing from here. Krea 17:16, 5 March 2007 (UTC)

I have placed a revised lead section on the article using some of the changes suggested by Fill. This is hopefully very simple to grasp, and technically accurate. Krea 17:03, 5 March 2007 (UTC)

• Perhaps it is not best to begin the page with a photo and a caption that most people will not understand (I am a graduate student in English literature who avidly reads popular science books)? My logic went like this: I thought hydrogen usually had one electron in the s-1 orbital, so I drew the conclusion that that box would be the brightest. Obviously, I am totally misunderstanding something. Awadewit 12:20, 16 March 2007 (UTC)

• For an article of this size, don't you need a longer lead? Awadewit 12:20, 16 March 2007 (UTC)

• The picture itself is perfect in a physics article, but perhaps the caption should be reworded. The lowest energy electron in a hydrogen atom is 1s, but if it is excited, it can be 2s, for example. How about "The first few orbitals for electrons of different energy and angular momentum in a hydrogen atom, shown as cross-sections with color-coded probability density." Would that be any clearer?
• The lead, if it were styled in the manner of other articles, would simply be too long. The introduction section is really the equivalent of a lead in other articles. Krea 01:06, 17 March 2007 (UTC)

Essentially, the article is nice, but for an article of this size, the lede should be significantly larger. It should be in the order of two to four paragraphs. Titoxd^{(?!? - cool stuff)} 23:26, 30 March 2007 (UTC)

I added more material to the lede. Other contributions are welcome. --Ancheta Wis 02:56, 1 April 2007 (UTC)

The problem is that for an article of this size, the lead will become too big. I've made a rough attempt, building on the outline suggested by Ancheta Wis both here and in the introduction section, and you can see how large it is! Krea 05:59, 2 April 2007 (UTC)

Can anybody explain to me how can the equation p=mv (in the picture at the bottom of the lead page) be considered a statement of Newton`s first law? Dauto 15:16, 7 April 2007 (UTC)

The first line is not merely a definition. It encapsulates the experiments of Galileo. I got the equation set from p. 23, Sander Bais, The Equations ISBN 0-674-01967-9. It was so clear to me that I put it in the encyclopedia. But I can understand why you might want to see more.

Here is the classical statement of Newton's first law

• A "Unless acted upon by an external force,

• B an object at rest tends to stay at rest and

• C an object in motion tends to stay in motion with the same speed and in the same direction."

Which when I first heard it, remains in my mind as "Objects in motion tend to remain in motion; objects at rest tend to remain at rest."

A relevant note is from R.S. Westfall, biographer of Newton, Never at Rest (referring to Newton's mind, which was never at rest).

• "Objects are indifferent to their motion". ^[1]

I think we can agree that A about is about Newton's 2nd law. So let's leave that for now.

Similarly, I think that we can leave B, as this is something Aristotle might have said.

That leaves C. The p is the inertia of some body. The conjoint quantity mv is Newton's take on the components of the inertia of that body, for which he is indebted to Galileo. So how did Newton see through Aristotle's B. The way that Galileo got past the state of rest was to set up an experiment which minimized friction. He used a very smooth, round, hard bronze ball, which he rolled along a length of molding, lined with parchment, which he polished until it was very smooth. This got rid of the friction acting on the ball. The set of experiments Galileo performed convinced him that the horizontal component of the ball's motion was independent of the vertical component, which we encode with the vector notation v and p. This is documented in Galileo, 1638, Two New Sciences^[2]. Salviati is Galileo's proxy when speaking about the horizontal motion of the bronze ball being independent of the vertical motion, and how the ball would roll indefinitely in the horizontal direction. Now it took Newton to see that the vertical motion of the ball would be indefinite as well, and he has a diagram of an artificial satellite to show how the motion of a ball under the influence of an inverse square law would be an ellipse. But that is line 2 of the picture. Line 3 of the picture has the principle of equivalence in it, so there is a lot packed into those three equations. --Ancheta Wis 19:30, 7 April 2007 (UTC)

1. ^ R.S.Westfall, The Construction of Modern Science ISBN 0-521-29295-6 p. 20
2. ^ I highly recommend Stephen Hawking's edition On the Shoulders of Giants ISBN 0-7624-1348-4 which reprints the relevant work of Johannes Kepler, Nicolaus Copernicus, Galileo Galilei, Isaac Newton and Albert Einstein if you want to read more. It can be purchased in parts, so you can pick up the Galileo section alone, if that is all you can afford.

I remain unconvinced. I see the first law as a spcial case of the second. But even assuming I`m just being dense, it seems inapropriate to have such non-standard view of what the Newton`s first law is, right there at the begining of the article. Just my opinionDauto 05:06, 8 April 2007 (UTC)

I used to think that too. But if you read Galileo, the importance of equation 1) becomes more apparent. After all, it was 2009 years between Aristotle and Principia. It is not for nothing that Galileo is the father of Physics. But re-reading Sander Bais, I see that he refers to 'Newton's Dynamical Equations'. Might that be a better caption. Bais also inserts Universal Gravitation as a line 4. --Ancheta Wis 09:13, 8 April 2007 (UTC)

The caption now follows Sander Bais. Ancheta Wis 10:00, 8 April 2007 (UTC)

I am searching thru Principia for the diagram of the artificial satellite's orbit, which I propose putting in the Applications section of the article. --Ancheta Wis 19:37, 7 April 2007 (UTC) Naturally it's in Wikipedia: Newton's cannonball. I continue to seek the pg. num. --Ancheta Wis 02:18, 8 April 2007 (UTC)

I am pretty sure the cannonball picture is in Cajori's translation of Principia, but I do not have ready access to Cajori. --Ancheta Wis 09:13, 8 April 2007 (UTC)

Newton's first law is indeed very important; in a way more so than the other two. What it really expresses is the framework within which the other two rules apply. It says that one can construct a reference frame in which bodies at rest and linear motion remain so. In this frame N2L and N3L also apply. Of course, from here we can ask deeper questions (one's which lead people to see N1L as a special case of N2L), but I'll leave that for now. As far as I understand it, I also don't quite see how p=mv represents N1L. p=mv in all frames, and so this statement says nothing about the construction of these special, inertial frames (which is where SR gets its name), which is what N1L is really about. Sorry, Ancheta, but I think I must have missed the point of your argument: what is the significance of p=mv that I am missing? Krea 12:44, 8 April 2007 (UTC)

I withdraw the association of equation 1) with N1L and follow Bais, retaining it as a definition of p. The caption follows Bais' denotation as 'Newton's dynamical equations'. --Ancheta Wis 16:26, 8 April 2007 (UTC)

[edit] Introduction

• Beginning with a multi-dimensionsal universe example is again a bit mind-stretching for many people. Even the words "spatial" and "temporal" are a bit difficult (sadly, I know this from teaching endless sections of freshman composition). I know you link them, but I have feeling that readers don't click on links as often as we might like to them to. Who are you imagining is the audience of this page? I am thinking high-school students or early college. Awadewit 12:22, 16 March 2007 (UTC)

I am reminded of a comment that Feynman made in class once: 'the 3-D nature of space is the reason for the form of Newton's law of gravitation' -- he stated that if our world had higher dimension, the inverse-square law would not be true. Krea probably has a citation for this fact. --Ancheta Wis 18:36, 17 March 2007 (UTC)

• The distinction between "general properties of nature" (I suppose you mean things like the "law of conservation of matter" or something like that?) and the "properties of certain objects" needs to be made more clearly - I would give it its own paragraph. Does studying objects lead to the discovery of general properties? Awadewit 12:22, 16 March 2007 (UTC)

Yes; this is the history of physics. The atomic theory was proposed thousands of years ago and suffered scorn as recently as 1900, by Ernst Mach. Now that we can image atoms and have waged wars with their power, we have more concrete evidence for the reality of some of the costructs of physics.

• I think the scientific method should be mentioned earlier so that it is clear physics is a hard science - mention it in the first paragraph right up front. Awadewit 12:22, 16 March 2007 (UTC)

And before scientific method, physics was more of a soft science. --Ancheta Wis 18:34, 18 March 2007 (UTC)

• As the evolution controversy demonstrates, it is imperative to define scientific "theory." I would also explain "falsifiability." Awadewit 12:22, 16 March 2007 (UTC)

Perhaps a link is one approach to the definition, so as to concentrate our efforts on the article.

• I think some of the "Scientific method" section can be condensed, specifically how physicists use other fields' tools. There is also some repetition regarding experimentalists vs. theorists. Awadewit 12:22, 16 March 2007 (UTC)

• This is because of the areas which physics has addressed are more amenable to quantitative approaches than other areas. - be explicit - explain Awadewit 12:22, 16 March 2007 (UTC)

See the comment about history of physics above. Atoms can be viewed as mass points, allowing the geometrization of physics. --Ancheta Wis 18:49, 17 March 2007 (UTC)

• There is a large area of research intermediate between physics and mathematics, known as mathematical physics. - why is this sentence repeated verbatim at least twice (if not more) in the article - it is jarring for the reader Awadewit 12:39, 16 March 2007 (UTC)

• "Relation to mathematics and the other sciences" is very repetitive and not quite coherent. It also repeats ideas that have already been said. Awadewit 12:39, 16 March 2007 (UTC)

Removed the first paragraph and credited Galileo in the first sentence of 4th paragraph. --Ancheta Wis 17:29, 18 March 2007 (UTC)

• "Philosophical implications" - not fleshed out enough - the first paragraph of the section is more relevant to "history" - the second paragraph is hard to understand unless you already know the quantum issues, etc. - add more or delete Awadewit 12:39, 16 March 2007 (UTC)

More citations to come --Ancheta Wis 18:34, 18 March 2007 (UTC)

• Although I am trying not to comment on small writing issues because this article has obviously not been revised yet for general prose issues, I must mention this sentence: These theories were largely couched in philosophical terms, and never verified by systematic experimental testing as is popular today. - "popular" - it sounds as if the scientific method is a fad Awadewit 12:39, 16 March 2007 (UTC)

Some excellent points are made here.

• "Spatial" and "temporal", I agree, should really be replaced with "space" and "time": there is no need for over-complication. Now, the problem is that I don't know of any other general property of nature that can be used as an example. The concept of space and time is understood by anyone, even if only superficially. I think I'll reword that bit to essentially ask "Why don't we live in a 2D world?" but in a more user-friendly way. If you can think of an easier example, let me know and I'll use that instead. The target audience (that I am aiming for) is late primary school onwards (who are interested in physics), so 10+ years old.

Perhaps you mean smart ten-year-olds or even brilliant ten-year-olds? The reason I say this is because the vocabulary and syntax of this article is much too advanced for a ten-year-old. Many of the concepts are also way beyond them. Next time you are at a bookstore, you might go to the children's section and pick up some books labeled "8-12 years." I'm not saying such an article isn't possible, I'm simply saying this isn't it. Sadly, I do not believe that even the bulk of my freshman composition students could understand this article. Awadewit 07:13, 17 March 2007 (UTC)

Ok, I was a little vague! I want a smart 10 year old to be able to get the jist of the basic principles of physics - not to understand the the more technical bits. I want parts of the article to be of value to everyone aged between 10 to 18. This is a tough ask, but I am trying to aim for contraints of comprehension that are due only to the concepts themselves, not how they are worded. As it is, you're right: it's a mess and it needs work, but we're working at it! Krea 00:44, 18 March 2007 (UTC)

• That's a good point. I'll try to do that. Your question is actually a lot deeper than it first appears - I'll have to give that some more thought before I can give a satisfactory answer I'm afraid.
• As for the rest of the points you make, I intend to rewrite the sections after "scope and goals", and I'll try to address the points that you make if they are still valid. I think that the scientific method probably should come first: depending on how I structure the rest of the sections, I'll try to do that. Krea 02:11, 17 March 2007 (UTC)

[edit] History

• The history section sounds more like a history of science than a history of physics. Please explain the history of physics in particular in more detail or explain why the features you have chosen to highlight are important to the history of physics (I suspect it is the latter that is relevant here). Awadewit 12:39, 16 March 2007 (UTC)

Physics was originally natural philosophy and did not split off from the other sciences until the nineteenth century. Thus astronomy (1543), and even biology (1780) were not separate sciences. --Ancheta Wis 23:37, 17 March 2007 (UTC)

• You mention "classical mechanics" for the first time in the "Scientific Revolution" section (as well terms like quantum mechanics, quantum field theory, blackbody radiation...). A lay reader may not be familiar with those terms. Try not to make this page one that would take hours to read due to clicking. Also, think about how difficult some of the pages you are asking people to click to might be. Awadewit 12:39, 16 March 2007 (UTC)

'Classical mechanics' is a term of the twentieth century, during which 'quantum mechanics' emerged. I personally deplore the term c.m., as the topics of physics are not separate; each of the topics is still useful and vital. CM is a limiting case of other theories, for example.

In the Feynman Lectures on Physics Feynman assumes that it takes years to learn physics. It is possible to teach classical mechanics on a child's playground, which is the approach of Physics First. --Ancheta Wis 11:05, 18 March 2007 (UTC)

• The History section is non-chronological - why do we go back for thermodynamics, another subfield you might define. Awadewit 12:39, 16 March 2007 (UTC)

I propose another technique than strict chronology, taken from the movies: the cross-cut: in this way we can take a specific theme in physics, such as the atomic theory, or electromagnetism, or spectroscopy, etc., and follow it as we would the protagonist in a story. --Ancheta Wis 17:10, 18 March 2007 (UTC)

• In relation to the other sections, the "History" section seems rather long. It should probably be tightened up. The essence of physics is not its history, right? Awadewit 12:39, 16 March 2007 (UTC)

Disagree: the evolution of ideas over the past several millennia is an essential part of the civilization. For example the atomic hypothesis/theory proposed two thousand years ago only came into mainstream thought in the last century. --Ancheta Wis 23:37, 17 March 2007 (UTC)

[edit] Branches of Physics

• Define quantized in the "Classical, quantum and modern physics" section. By the way, I would move this section up before the history section - it will help someone understand the history section. Awadewit 12:39, 16 March 2007 (UTC)

User:Joke137, a physicist, and others have already proposed that History be moved to the location you see now. The outline was agreed upon after extensive discussion. See archives. --Ancheta Wis 07:13, 18 March 2007 (UTC)

[edit] Current Research

• I really like this section, but I would try to make it sound even more exciting. Make someone want to be a physicist! What are the burning questions physicists want to answer? "What is dark matter? Why does it make up the majority of the universe?" etc. Awadewit 12:39, 16 March 2007 (UTC)

  This is but an example of "the horrible condition of our physics today" as Feynman put it. --Ancheta Wis 11:01, 5 April 2007 (UTC)

[edit] Applications and Influence

• It would seem like you could work the "Applied fields" boxes into the prose somehow - must you list them all? Awadewit 12:39, 16 March 2007 (UTC)

Done. Ancheta Wis 10:57, 5 April 2007 (UTC)

[edit] See Also & External Links

• I would suggest renaming the "Mainstream physics" links merely "Physics" - don't descend to the adjective - claim the field; "mainstream physics" suggets that there is an "alternative physics" - don't suggest that Awadewit 12:39, 16 March 2007 (UTC)

[edit] Miscellaneous

Feynman was one of my teachers (perhaps I might upload a picture of the Feynman diagram he inscribed in his Quantum Mechanics volume for me -- if you can't read the symbols, they are γ_μ to γ_μ and 1 / q²). I would like to include pictures of the equations of physics in the wip page, as iconic representations of the principles of physics. --Ancheta Wis 05:50, 2 March 2007 (UTC) Cut from a larger post (See here). Krea 17:03, 5 March 2007 (UTC)

I think it's a good idea, especially in the "Current Research" section. However, careful not to include too many equations, they might put some readers off. I'm sure you, and certainly, I would love to see equations splatted all over the place, but some readers would disagree that an equation is more beautiful to look at than a picture - especially all the time! Also, could you try to make the image a little clearer somehow? Krea 17:13, 5 March 2007 (UTC)

Krea, I reloaded an equalized picture. --Ancheta Wis 19:18, 11 March 2007 (UTC)

It's good enough, I think, unless somebody takes a better quality one. Krea 19:54, 15 March 2007 (UTC)

• I wonder about including a description here or there of a famous experiment (gold foil, for example), to demonstrate in concrete terms what (some) physicists do. Besides, Rutherford's quote about cannon balls and clouds is quite descriptive. Awadewit 12:39, 16 March 2007 (UTC)

I agree. I'll try to include some when I eventually get to taking a look at the other sections (I am "concentrating" on the introduction section for now). Krea 02:22, 17 March 2007 (UTC)

• Hi all I don't have a suitable picture, but I think that there should be even a Galileo portrait in the article.. if I find a picture I'll try to add that but I hope someone could help Tatonzolo 23:47, 22 March 2007 (UTC)

I agree. We should try to sneak a picture of one of the most important people in the history of physics somewhere in the article. The Galileo Project has a few nice portraits that are, I think, freely available because they would either be out of copyright or come under fair use. Krea 23:23, 27 March 2007 (UTC)

Wait, there already is a nice portrait in the article! It might not survive, however, since the history section needs drastic modification. In this case, I hope we could use it elsewhere in the article in an appropriate place. Krea 23:28, 27 March 2007 (UTC)

[edit] Fringe

Ive removed aether from the fringe theories list as its not really a fringe theory as an expired theory. Its was superseeded by special relativity. If anyone disagrees let me know! CaptinJohn 16:59, 9 March 2007 (UTC)

• Why are these fringe theories even included on a basic physics page? When I think "fringe" I think crackpot. Are these theories that might be proved one day like string theory (if someone could devise an experiment)? I thought cold fusion was impossible.

The word "fringe" is ambiguous: it could be interpreted as a theory lacking observational verification but expected to be confirmed, or a crack-pot theory. I'd remove "fringe" altogether. The former theories should be placed in the "Current Research" section; and for the latter, perhaps a paragraph and then links to other articles. Krea 01:01, 18 March 2007 (UTC)

[edit] Admin

Pascal.Tesson on the Physics talk page brings up the valid point that anything that we do should really be placed in talk or user pages. So, how about moving the Physics/wip article to Talk:Physics/wip/article, and Physics/wip/leadproposal1 to Talk:Physics/wip/leadproposal1/lead1 etc.? Krea 03:40, 16 March 2007 (UTC)

Is there a Wikiproject space? We have to keep it out of Talk at alll costs. That is why there was so much talk in the first place. --Ancheta Wis 10:35, 16 March 2007 (UTC)

I don't know if there is a wikiproject space, but we'll just place the article in a talk page - we won't actually do any talking! Krea 00:48, 18 March 2007 (UTC)

These pages *must* be moved in order to comply with policy. See Wikipedia:Subpages#Disallowed uses. Gnixon 20:59, 26 March 2007 (UTC)

Thanks, Krea, for saving the history. I was lazy about how I moved it. You may want to do the same for the leadproposal pages. Gnixon 00:00, 28 March 2007 (UTC)

Apologies for altering the Welcome box without logging in. I didn't realize my session had expired when I made the change. --Ancheta Wis 10:40, 28 March 2007 (UTC)

That's fine Gnixon, I'll do the leadproposal pages too at some point. Krea 06:00, 2 April 2007 (UTC)