Talk:Electric charge

Start of Electric charge

In the Electricity article, electricity is defined in terms of electric charge, and electric charge is wiki-linked. Therefore, article on electric charge needed. Hope others will contribute, especially physicists, chemists, and historians of science. —Anthony.Sebastian 02:16, 6 July 2011 (UTC)

Coinage of electric, electrical

A number of sources attribute the coining of the word "electric" as referring to electrical phenomena to William Gilbert. For example, Weinberg. A more elaborate discussion is given in Wikipedia where a distinction is made between the introduction of electricus by Gilbert in his Latin text, and the use of electric in English by Francis Bacon. That is also the approach of the online etymology dictionary. It appears from Anthony's text that the Webster's Third New International Dictionary has an attribution for electric that pre-dates Gilbert. I can't access this link, so I don't know just what Webster's dictionary means. How is this to be handled here? John R. Brews 22:51, 27 July 2011 (UTC)

The Oxford English Dictionary, third edition, March 2008; online version June 2011, under the entry ‘electric’, states “apparently earliest in W. Gilbert De magnete (1600)”, and also states “compare slightly earlier ‘electrical’.

Of course, Gilbert wrote in Latin, and if he actually used the word 'electric' it certainly wasn't the first Latin work in which 'electric' was used, as a Google Books search for 'electric' in books before 1600 reveals.

Re Wikipedia: I note the following first two quotes for 'electric' in the OED:

a1626 F. Bacon Physiol. Remains in Baconiana (1679) 149 Crystal, Lapis Specularis, Glass, and other such Electric Bodies, if burnt, or scorch'd, draw not.

1646 Sir T. Browne Pseudodoxia Epidemica ii. iv. 78 By Electrick bodies, I conceive‥such as conveniently placed unto their objects attract all bodies palpable.

Re 'a1626' for F Bacon: The OED says "The date of publication is placed at the head of each quotation. For older texts, especially for those dating from before the invention of printing, this date may be a manuscript date or the date at which the text is thought to have been composed. In the case of posthumously published books, the date normally given is that of the author's death (preceded by a = 'ante')." Anthony.Sebastian 03:26, 28 July 2011 (UTC)

Somewhat confusing, eh? Anthony.Sebastian 03:14, 28 July 2011 (UTC)

Hi Anthony: I'd say so. I guess one can nit pick over it, but I'd suggest the approach you outline: indicate that in Latin words were coined that resembled the Greek for "amber" and these were made common following their usage in Latin by Gilbert, and subsequently were taken over into English in the forms "electric", "electron", "electrical". Would you agree to phrase this somehow in the article? John R. Brews 03:33, 28 July 2011 (UTC)

Will do, John. May take a few days to get to it. Thanks for stimulating the re-think. More sections also aborning. Anthony.Sebastian 03:47, 28 July 2011 (UTC)

Definition of electric charge

A problem with the present definition is that it seems to apply equally to magnetism, an issue Gilbert identified and tried to explain away. I don't understand Gilbert's way to distinguish between them, but something is needed. John R. Brews 03:37, 28 July 2011 (UTC)

The point is perhaps clearer if one looks at a discussion of the inverse square law, which is the same for both magnetic and electric charges. It appears that some additional phenomenon has to be introduced to cause recognition of two distinct types of charge. John R. Brews 03:54, 28 July 2011 (UTC)

One possibility is the observation that while electric charge can be transferred from one body to another, while the overall charge is conserved, but all magnets have zero net magnetic charge, and this situation cannot be altered. See this and this. This inability might be the litmus test for whether a charged pair of bodies are magnetically or electrically charged. John R. Brews 04:09, 28 July 2011 (UTC)

The present definition of electric charge is, in fact, a definition of charge, not a particular kind of charge. See this, for example. A charge is a property leading to a force, and need not be electric. John R. Brews 13:19, 28 July 2011 (UTC)

I have modified the definition and the introduction accordingly. John R. Brews 14:31, 28 July 2011 (UTC)

Apparently color charge should be mentioned as well. John R. Brews 15:54, 13 August 2011 (UTC)

The author of the reference you give for the definition of charge admits it is heretical. Even if it weren't, 'electric charge' would still admit of a definition, but perhaps not the present one. I'm working on a new definition of electric charge that I hope will be specific to electric charge. Anthony.Sebastian 22:06, 18 August 2011 (UTC)

Definition

The present definition is (i) too long, (ii) too flowery, and (iii) incorrectly emphatic of protons and electrons. It correctly emphasizes the separability of positive from negative charge, but fails to note electric charge occurs in multiples of a discrete unit, the elementary charge e, in SI units 1.602 176 565 x 10^-19 C . John R. Brews 14:07, 20 August 2011 (UTC) The definition mentions repulsion of like charges. This phenomenon is a manifestation of the observation that moving charges are origin of electric current, and that charges and currents together are the sources of the electromagnetic field, the origin of all electromagnetic forces. John R. Brews 14:25, 20 August 2011 (UTC)

I agree, the definition I proposed uses more words than customary for CZ definitions, but arguably it uses just as many words as needed for a precise introductory definition of electric charge accessible to a non-expert. I will reexamine to see if I can shorten it.

Regarding 'too flowery', I'm not sure precisely what you mean.

Regarding "incorrectly emphatic of protons and electrons": I start with the premise that, primordially, electric charge manifests itself in the form of protons and electrons. Admittedly it goes deeper, but understanding the phenomena and applications of electricity requires understanding of electric charge in terms of protons and electrons. Isn't that what we have to do to move on to electric forces and fields, conduction, induction, etc.?

Regarding what the definition fails to mention, those considerations do not necessarily belong in the core definition, but do need to be early added to fully describe electric charge. The facts that electric charge attractions and repulsions reflect fundamental forces, and that electric charge has quantity, and that quantities of electric charge are multiples of a discrete unit, provide the elements of the narrative—an elaborated definition if you will—but arguably can follow an introductory definition. I prefer leading up to such elaborations as a methodology to give the non-expert reader the ABCs serially in a coherent narrative.

I realize you are an expert in this field, and I am not. But, as a non-expert, I need a narrative that walks me through the concept step by comprehensible building block step. Anthony.Sebastian 21:29, 20 August 2011 (UTC)

Hi Anthony: Thanks for engaging. I've tried to modify the definition as you have seen. It's probably still too complex. John R. Brews 22:02, 20 August 2011 (UTC)

To John: Would you object to my starting a 'Student Level' subpage, as a trial?

John, I find your Introduction to Electric charge nothing short of outstanding.

However, I do not find it elementary enough to teach a student, a secondary school student, say, who wants to learn the ABCs of electric charge step-by-step from first elementary principles.

Unless the content of the student level is wrong or misleading, I personally see no harm in CZ providing both a Main Article and a Student Level article. As you know, CZ provides an official subpage for a student level treatment of a topic. The student level subpage would, of course, be subject to your Editorial guidance.

I suggest this to avoid further disagreements on the approach to the Main Article. I would not put up the subpage until I'd developed it substantially. Anthony.Sebastian 21:59, 20 August 2011 (UTC)

Hi Anthony: It may be that your more approachable article will lead to improvements in the present article. As you know, a building-block approach is not so easily accomplished, especially if you have objectives of being brief, and simple, and accurate. I hope you can do that.

Maybe, like me, you have read enough technical articles to have a built-in editor that skips stuff you can't absorb on first pass and returning later if some points need more attention. So, a reference to a photon needn't be understood to get the drift, but it may prove disconcerting to some. It will be interesting to see how this works out. John R. Brews 22:12, 20 August 2011 (UTC)

John, I appreciate your gracious note, and wise words. The truth is I know very little about electricity and magnetism, but have a great desire to learn. One way I use to learn is to write about what I want to learn, to try to discover the limits of my knowledge in the narrative, advance a little by research, and rewrite until I feel a reader like me will have the easiest possible time understanding. Writing to learn and teach, writing being rewriting. Having a mentor helps a lot.

As to the issue of brevity, I tend to concern myself with that late in the writing process, another component of rewriting. I tend to subscribe to "repititio mater memoriae/studiorum". I try to keep the reader always in mind, and I always presume the experts do not mind reading what to them is elementary. Paul Wormer has said I write as if I'm writing for a children's encyclopedia.

Of course one has to start writing assuming some level of knowledge on the part of the reader. What to assume is always the hard part for me. Anthony.Sebastian 02:03, 21 August 2011 (UTC)

Anthony: The process you describe of learning, writing, reading and rewriting is a digestion of the subject that can be very helpful to the reader in a way that the existing literature cannot. Existing explanations are focused upon students who intend to spend a lot of time on the subject to develop perspective, or upon experts who don't need perspective filled in. Of course, the downside to your approach is that the digestive process will be ongoing, assuming your interest can be maintained for some time, and so the article will evolve, and may not begin as well as one might hope. I've seen articles on CZ written by experts unable to explain things for non-experts (and hostile to suggestions to do so), and articles on CZ written by non-experts who appear to have taken very little trouble to understand what they are talking about. So there is a continuum here, and attacking the issue as you describe may be a good middle road. John R. Brews 17:51, 22 August 2011 (UTC)

Peter's definition

Peter:

Your definition of electric charge, namely:

A physical quantity of matter relevant in connection with electromagnetism

conveys absolutely nothing to me. First, "charge" is not a physical quantity of matter. Maybe it could be said to be "a property of some matter". Second, relating "charge" to "electromagnetism" is somewhat like defining "number" as "relevant in connection with mathematics".

Where do I find the rules of definitions that you have found to be violated, and in what manner did the previous definition violate them? Probably of more importance is just what precipitated your reaction to the previous definition:

A fundamental property of matter underlying electricity and electromagnetism, which occurs in positive and negative forms as integer multiples of an elementary charge unit, and which causes charged particles, which can be isolated and spatially separated, to exhibit mutual repulsion when identically charged, and mutual attraction when oppositely charged.

I could well understand that this definition is indigestible, but before trying again, I'd like to be clear what the guidelines are.

Thank you for taking the time to raise this issue. John R. Brews 18:05, 22 August 2011 (UTC)

Here's a shortened proposal:

A positive or negative property of matter that occurs as integral multiples of an elementary charge unit, and causes mutual repulsion of like-charged particles and mutual attraction of oppositely charged particles.

It doesn't include the important property that positive and negative charges can be observed separately, which distinguishes electric charge from magnetic charge, but perhaps brevity is more important? John R. Brews 19:04, 22 August 2011 (UTC)

I found the desiderata for definitions at CZ:Definitions. The only criterion violated by the original definition that I can identify is one of length. The new proposal is close to the thirty word limit suggested. John R. Brews 15:57, 23 August 2011 (UTC)