Talk:Potential

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Template:Physics

Reddi edits

User:Reddi keeps adding the following edits. At the beginning:

A Potential, generally, is the inherent ability for coming into being.[1] These are states that something can achieve. This concept is related to probability.

and, at the end, under Engineering:

In mechanical work, machines transmits (or modifies) energy to perform or assist in the performance of human tasks. It's potential energy exists because of the relative positions of two or more objects. [2] This potential is measured in foot-pounds (ft-lb).
In Electric circuits, potential is the voltage at a point relative to some reference point. [3] It is the ability of the electromagnetic's magnetic force's ability to push one Ampere of energy through one ohm of resistance. The magentic force oscillates the the current in circuits. This is also know as Potential differences.

My objection to these are as follows:

  • First of all, we assume that readers of the English Wikipedia speak English; there's no need to define the ordinary English meaning of the word (Wikipedia is not a dictionary), especially when the article begins in physics. Even if you want to do so, if you look in a good dictionary you'll find more varied and more sophisticated definitions than "the inherent ability for coming into being".
  • Second, I'm not aware of a specific technical meaning (beyond ordinary English) of "potential" in probability theory; if there is one, the oblique reference you give is insufficient. (Note that in statistical and quantum physics, there is a relationship between probability and potential energy, but potential there is still being used in the sense the article already describes.)
  • The potential energy used for mechanical work (i.e. classical mechanics) is exactly the "physics" meaning for potential energy already described in the article; there is no separate "engineering" meaning. (foot-pound is just a non-metric unit for energy, by the way; no reason to cite it specifically here.)
  • The potential used for circuits is also no different from the electrostatic potential already described, plus emf as already described; again, there's no separate "engineering" meaning. Also, your definition here is garbled, and not just grammatically; one of the strange facts of electromagnetism is that magnetic forces can do no work (because they are always perpendicular to the direction of motion of the charge); they can only do work indirectly via the induced electric field of Faraday's law.

—Steven G. Johnson 05:17, Apr 7, 2004 (UTC)

I made a a disambiguation page. Moved the physics stuff here. JDR

This is simply avoiding the issue. The point is that, other than the ordinary English meaning (which Wikipedia does not try to define anyway), there are no substantially different technical usages of Potential. Reverted. —Steven G. Johnson 06:12, Apr 7, 2004 (UTC)
Wikipedia is not a dictionary ... but when disambiguation is needed for CLARITY, such a page is used ... it's an inclusion vs exclusion thing here ... you want to exclude the info ... I want to include it ...
not "technical" ... but wikipedia uses the common terms [read as "laymen"] ... "potential" (in a general sense) deals directly with probability, the article need a link to it ...
"engineering" meanings are to reference the associated pages ... (BTW, I know the diff of the american - metric units ... and there isn't a real reason why they shouldn't be referenced)
"potential used for circuits is also no different from the electrostatic potential already described"? no .. the concepts are not explicitly mentioned ... that's why I have an' will add the info ...
"garbled and not just grammatically"? sure ... whatever ...
BTW, the magnetic field "pushes" the elctric field through the conductor ...
Sincerely, JDR (knows this is a direct result of the axiom about substituting mathematics for experiments)
PS. gonna post a factual inaccuracy tag ...


You really shouldn't edit topics that you so clearly fail to comprehend. And as for "clarity"...well, the samples of your writing do not speak eloquently of your judgement in that regard. —Steven G. Johnson 17:55, Apr 7, 2004 (UTC)

A lay-definition

"In physics, a potential is a scalar field used to describe a conservative (curl-free) vector field, such that the vector field is the gradient of the potential."

Whoa, can't we get a simpler definition for that first sentence? This is an encyclopedia, not a physics textbook. anthony (see warning) 23:41, 10 Apr 2004 (UTC)

I'll try to make a more accessible topic sentence. —Steven G. Johnson 22:16, Apr 11, 2004 (UTC)

Don't copy/paste move

Don't perform moves by copy and paste. This destroys the page history. anthony (see warning) 23:46, 10 Apr 2004 (UTC)

Sorry. Reddi had moved the page to Potential (physics), and Wiki didn't allow me to simply move the page back because the Potential page he replaced it with got in the way. It looks like you solved this by moving Potential to another, temporary name; I didn't think of that.

Potential of a quantum field?

The sentence beginning with "In quantum theory" is at best unclear and at worst wrong. If someone (the author?) knows what was meant, could e please explain so it can be improved? My attempt at an interpretation would be that it refers to an "effective potential" that can be derived from the photon field, but it's a bit unusual to speak of the "wave function" of a photon. Fpahl 08:58, 22 Sep 2004 (UTC)

That sentence was written by the anonymous author of the initial version of this article. I agree that it's too difficult to tell what exactly he/she meant, and I removed it. —Steven G. Johnson 15:48, Sep 27, 2004 (UTC)

Potential of (Isolated) Sphere

The potential of an isolated sphere is defined as the work done in bringing a unit charge from infinity upto the sphere. So what is the potential at infinity?? Any comments welcome. Light current 02:05, 6 August 2005 (UTC)

See Electric potential#Mathematical introduction. The potential at infinity is zero by definition. --Smack (talk) 02:40, 6 August 2005 (UTC)
So if the sphere is not now isolated but is a sphere at the top or a Van de Graaf generator (say) whose refence terminal is connected to earth, where does the current from the corona discharge go?. To earth or off to infinity?? And if not infinity, Why not?Light current 18:59, 6 August 2005 (UTC)
As far as I'm aware, the potential at infinity is whatever one defines it to be. Setting it to zero simply happens to be convenient for some cases. —The preceding unsigned comment was added by 137.22.102.200 (talk) 07:40, 11 February 2007 (UTC).

intro sentence

"In vector calculus, any vector field of a certain type has an associated scalar field called the potential."

That sounds to me like the magnitude of the vector field. - Omegatron 03:46, August 6, 2005 (UTC)

Yes potential is a scalar quantity I seem to remember. The potential at point has no direction and does not depend upon the path the unit charge takes to reach it from infinity.Light current 06:54, 6 August 2005 (UTC)
Any vector field has a great many associated scalar fields, my friend :) --Smack (talk) 17:45, 6 August 2005 (UTC)
I think the intro sentence needs to be more explicit while also being easier for newcomers to understand. And yes, I know that sounds hypocritical.  :-) - Omegatron 20:58, August 6, 2005 (UTC)
Hypocritical? How so?
I tried to rewrite it to say "some vector fields" rather than "any v. f. of a certain type", but that almost sounds like all of these vector fields are associated with the same potential. --Smack (talk) 15:19, 7 August 2005 (UTC)

Correct?

Isn't eq. 2 supposed to be : ?

I think it's right as it stands. points in the direction of increasing . --Smack (talk) 04:20, 21 April 2006 (UTC)
anon poster was right, smack got it wrong, it should be negative. I merged those paragraphs into scalar potential where they belong. linas 21:46, 7 July 2006 (UTC)

Merge

I propose that the page potential (disambiguation) be merged into this page, as it almost completely overlaps this article. Also, some of Reddi's suggestions from above should be incorporated (who'd think I'd ever defend Reddi?). Namely, the literary definition: tha a potential is the possibility or likelyhood that something happen. This is indeed the historical origin of the term. Other useless stubs that should redirect here are potential difference and potential function. I was damned tempted to call for a merge of potential energy, except that that article is in decent shape, despite the fact that it overlaps this article as well as with scalar potential. linas 21:46, 7 July 2006 (UTC)

Oppose, mostly. Potential function should not redirect here, simply because a potential function and a potential are not the same thing. Someone who followed a link to "potential function" and wound up looking at "In physics, a potential may refer to..." would be very confused. Potential difference isn't quite the same thing as a potential either, but you can merge it if you insist.
Furthermore, we must keep a disambiguation page somewhere, simply because the term 'potential' is ambiguous. In that vein, I would suggest that the problem is not with the specific-potential pages but with this page itself. Maybe we should split it up and redirect it to Potential (disambiguation). --Smack (talk) 01:18, 8 July 2006 (UTC)

Oppose. Potential (disambiguation) should clearly stay, with potential function either redirecting to it or being its own article.

Also, Potential difference is not the same as potential as remarked above. Oleg Alexandrov (talk) 20:34, 8 July 2006 That Is Also Correct but the Potential difference is built on different things], not just dates and times. (UTC)

I dont believe these should be merged because they are two totally varying subjects, potential is a physics area within electrostatic fields and should therefore not be merged.

Voltage should rather be merged and redirect to potential difference for this is the correct technical term. 80.136.204.122 00:05, 7 October 2006 (UTC)

Disagreement with suggestion to merge pages.

I completely disagree with the proposal to merge the potential articles. There are different uses of the term potential in different areas of physics and mathematics. The definition that Mr. Johnson gave in this discussion is one that arises in classical mechanics, vector analysis, and fluid mechanics. It has a precise mathematical meaning, which is not the same as a potential difference, nor is it the same as an action potential, which has a precise meaning in biology. I recommend keeping these terms in separate articles.

The definition given by Mr. Johnson, (i.e., "a potential is a scalar field used to describe a conservative (curl-free) vector field such that the vector field is the gradient of the potential") is the accepted definition in physics and mathematics. I considered suggesting changing the term to "potential function," but in math and physics, the term "potential" is used. For references, I suggest any vector analysis book. For a higher level, very thorough reference, I suggest Kellogg's book "Foundations of Potential Theory."

As for giving a lay definition, it is really nice to read explanations of things in physics and math that are easy to visualize or grasp intuitively, but that may also cause a lot of the meaning to be lost. Maybe we could say something like this: A vector field is a kind of function or mapping that assigns a vector (a magnitude and a direction) to every point in space. We can imagine a fluid flowing in the directions indicated by the vector field, u. If the flow is rotational, then the curl of the vector field has a value that is not equal to zero. If the flow is not rotational, we say that it is "irrotational," "conservative," or curl-free (curl = 0). In this case, there is some function, F, such that the vector field u is the gradient of F.

This is still very technical, and I think the more concise definition should still be given. Links are needed to "scalar field," "vector field," "curl," "gradient," and, perhaps, fluid mechanics.

I also recommend referring to the Wikipedia article on "Conservative Vector Fields." The conservative vector field is the direction of the potential. I think the two articles should compliment each other in style and content. Alarussa (talk) 23:40, 23 November 2009 (UTC) Alarussa (talk) 23:38, 23 November 2009 (UTC)

23:03, 23 November 2009 (UTC) —Preceding unsigned comment added by Alarussa (talkcontribs)