Talk:Electrostatics

Cat

I like the picture of the cat — Preceding unsigned comment added by Owen Scieszka (talk • contribs) 16:15, 4 June 2022 (UTC)

Thanks. To keep the picture we had to fight a battle against other editors who thought it was inappropriate. --Chetvorno^TALK 16:53, 4 June 2022 (UTC)

I like it, too. Out of Phase User (talk) 02:22, 5 June 2022 (UTC)

I like it too, however, I wonder if a cat lover might think that this cat has been mistreated. This image was cropped from a larger image

Cat and styrofoam – electrostatic charge (235112299)

. I like this image better, since it is clear that the cat is not being confined and is free to shake off the Styrofoam peanuts. Constant314 (talk) 02:33, 5 June 2022 (UTC)

Maybe crop it halfway more and put it in. The original is cropped pretty tight, just aesthetically. Out of Phase User (talk) 21:40, 5 June 2022 (UTC)

Support The cat is here to stay. Alexceltare2 (talk) 21:55, 4 February 2023 (UTC)

Maybe we should add an easier way to find the full image on the page, since replacing the image with a slightly less tightly cropped version seems redundant. KurthyWurthy (talk) 21:04, 31 August 2023 (UTC)

Re: Electrostatics description that charges that are at rest or "static" || Partially correct statement?

A given situation can be both electrostatic and have a constant current density. Current is the amount of charge per unit time that flows through a chosen area. Therefore moving charges but the distribution of charges would be the same at any instance of time in such a case.

I then wonder if 'at rest' is an apt description. A teaching assistant in a course of mine had wrongly assumed that electrostatics also requires the current density to be zero because of the 'static charges' description. Would like some insight from others about this.

Also, this wiki page is all over the place but the cat is amazing. Spartie19 (talk) 21:48, 22 November 2022 (UTC)

In electrostatics, charge is at rest. There are no currents. Constant314 (talk) 22:14, 22 November 2022 (UTC)

The source that I consulted was "Field and Wave Electromagnetics" by David K. Cheng, 2nd edition. It does support the statement and it's also mentioned further down on the wiki page. Spartie19 (talk) 22:23, 22 November 2022 (UTC)

In as atom the electron causes magnetic effects it is not stationary. To look at the electrical attraction between the proton and an electron as a charge at rest while ignoring the well known magnetic effects without some clarifying remark of why they can be viewed in isolation is wrong. The electron is moving quite fast no matter what frame of refence is chosen Bill field pulse (talk) 22:15, 15 January 2024 (UTC)

Electrons are not part of electrostatics, so their motion is not relevant for this article. Johnjbarton (talk) 22:29, 15 January 2024 (UTC)

Seconding @Johnjbarton comment. The focus of this article is supposed to just be the forces between charges and not include motion. We tried to rewrite it to be clearer, is used to be a bit chaotic (look at the versions from early in 2023). This article does not include currents or other moving charge effects, the example is just a simple one. Ldm1954 (talk) 22:45, 15 January 2024 (UTC)

The article defines it much clearer than previous versions, especially under "Electrostatic approximation". I think my original comment may have been a bit pedantic. Nevertheless the wording and flow of the article lends itself well to explaining the concepts and I don't think my old comment applies to this current version. Spartie19 (talk) 06:31, 16 January 2024 (UTC)

To say the magnetic field due to electron motion in a rough circle is slow moving is incorrect. It changes extremely quickly hence "spin" (which is not conventional spin). Bill field pulse (talk) 16:36, 16 January 2024 (UTC)

This is about the classical body of knowledge known as electrostatics. It is about the theory of electrostatics. All ordinary objects are made of jiggly parts. We are not going to throw out all of electrostatics. We simply take "nothing is moving" as an assumption of the theory. Real life does not have to perfectly obey the assumption for it to be useful. That fact that all objects jiggle does not mean that the assumption that "nothing is moving" is not useful. It is "close enough". Constant314 (talk) 23:41, 15 January 2024 (UTC)

Shouldn’t we say something about why one of the most dynamic situations in nature can be treated as being equal to nothing is moving? Consensus Cheat (talk) 14:27, 16 January 2024 (UTC)

What situation would that be? Constant314 (talk) 14:50, 16 January 2024 (UTC)

I see you use bing chat

. They agree as follows: No, an atom is not static. An atom is made of smaller particles called protons, neutrons, and electrons. The protons and neutrons form the nucleus, which is the center of the atom. The electrons orbit around the nucleus in shells, which are like invisible bubbles. The electrons are constantly spinning and moving to stay as far away from each other as possible12. Sometimes, the electrons in the outermost shells can be pushed out of their orbits by applying a force. These moving electrons are electricity2. Static electricity is a form of electricity that occurs when electrons jump from one object to another, such as when you touch a metal doorknob after walking on a carpet3. Therefore, an atom is dynamic, not static. Bill field pulse (talk) 16:47, 16 January 2024 (UTC)

Your comments are scattered around so much that I am having a hard time trying to figure out exactly what you want to propose. Maybe you are proposing several things. How about starting a new thread and summarize how you propose that the article should be changed. Constant314 (talk) 21:02, 16 January 2024 (UTC)

I am happy the way the article is now devoted to net stationary or slow moving charges. I think the special electron proton situation did not belong, as it was before. It seems better suited to the electromagnetic field article where discussion of the whole electron motion topic is allowed. My intent is have the article make sense. Static electricity certainly fits with the original definition without clarification. Bill field pulse (talk) 21:36, 16 January 2024 (UTC)

This article is about electrostatics. It is not about static electricity or about atoms or about electrons. Johnjbarton (talk) 21:07, 16 January 2024 (UTC)

Electrons in atoms are 1% of c; even if the quarks are ignored. While Coulomb attraction is found in static cases as well, to ignore the magnetic effects without any clarifying remark is wrong.

Either clarification should be added or electron-proton attraction should be moved to the Electromagnetic field article where fast moving charges are being considered. Bill field pulse (talk) 16:21, 16 January 2024 (UTC)

I removed protons and added content disclaiming quantum effects. Johnjbarton (talk) 16:57, 16 January 2024 (UTC)

Can some of this be added to the electromagnetic field article?Otherwise, the special conditions for assuming a steady magnetic field are an electron circling in a fixed perfect circle having a fixed "spin" effect. Bill field pulse (talk) 17:12, 16 January 2024 (UTC)

I see the article as improved. I hope we don't revert in a few weeks as we did with the electromagnetic radiation drawing. I think the electron-proton situation deserves a place in electromagnetic field article. Bill field pulse (talk) 17:21, 16 January 2024 (UTC)

Please remember that exchange-correllation is only a minor (but important) term on top of the dominant VXC, and spin-orbit is some orders of magnitude smaller. I edited the article slightly so readers don't get the incorrect idea that Coulomb forced don't matter in QM. Ldm1954 (talk) 17:43, 16 January 2024 (UTC)

orders of magnitude

k = 9x10^9 N·m^2·C^−2 q1 = q2 = 1.6x10^-19 C q1 x q2 = 2.6^-38 C^2 q1 x q2 x k = 2.3x10^-28

G = 7x10⁻11 N·m^2·Kg^-2 m1 = 1.7x10^-27 Kg m2 = 9x10^-31 Kg m1 x m2 = 1.5x10^-57 m1 x m2 x G = 1.1x19^-67

(q1 x q2 x k)/(m1 x m2 x G) = 2.1x10^39 Pediadeep (talk) 01:05, 16 November 2023 (UTC)

What we need is a reference, a source that shows this calculation is valid. Otherwise its WP:Original research. Thanks! Johnjbarton (talk) 01:26, 16 November 2023 (UTC)

This comes without reference, like it was with the claim of 36 orders of magnitude as it was before.

This calculation is pure simple low level mathematics combining physical constants, Coulombs law, and the law of gravity. It is trivial and stated here just for reference on its own.

I can understand the objection, but finding an external reference for this is (about) like finding a reference for stating that a car travelling with 100 km/h will make 28 meters in a second.

Sorry.

If I can not convince the community, we have to delete the entire statement, including the numbers. Pediadeep (talk) 20:31, 16 November 2023 (UTC)

https://www.texasgateway.org/resource/231-four-fundamental-forces Says $10^{-38}$ compared to strong force and electromagnetism is $10^{-2}$. Same on http://hyperphysics.phy-astr.gsu.edu/hbase/Forces/funfor.htm

https://www.huffpost.com/entry/myths-of-physics-2-gravit_b_5718233 says the comparison typically derived by comparing forces on an electron and proton don't make sense. Or rather the entire nature of the comparison is not sensible. Force is not an independent quantity that can be measured, it always depends upon the circumstances.

Gleick, James. Genius: The life and science of Richard Feynman. Vintage, 1993. On page 352 says $10^{42}$ but its not completely clear what setup that refers to. Johnjbarton (talk) 21:06, 16 November 2023 (UTC)

texasgateway compares against the strong force, what is only of limited help here because strong force is definitifely not a classic conservative force as can seen from their statement that it has a range of 10^-15 m as compared to the range of infinity for bothe gravitation and elecro(static).

hyperphysics website does not answer to me, so I can not reason about.

huffposts article is quite a strange reasoning IMHO, and can not be taken serious.

Both articles just STATE what they claim, without giving references or proofs.

The point is, that in classical physics, neglegting quantum physics and relativity, both, gravitation and coulomb, regard the respective forces to have a strict 1/r^2 dependency, and coulomb takes additional a factor of q1xq2, where gravition has a respective factor of m1xm2.

And it is general consensus that both laws hold true especially in distance ranges that are considered to be accessible by experiment, say, some millimeters to billions of kilometers (of course their is no experiment prooving the validity of coulomb to such big distances).

Both laws are tested and verified by experiment, as it is agreed by physical community and common sense.

Please note that I am talking about classical physics for particles in rest.

We could decorate this statements about relative strength of these forces, but that would actually blurr the meaning.

Take it this way:

You have an electron at rest and a proton at rest, separated by a distance of one meter, what would the actual force(s) be. How would you calculate these? How would you measure.

You could take electrons and positrons, protons or antiprotons or anything else. I think electron and proton is very telling, particular in this case.

Of course we should compare apples with apples and nothing else, and electrons are only very very little similar to protons, as we know, but both are considered to have rest mass and charge, and the values of these masses and charges are very good understood, measured, and documented. Pediadeep (talk) 17:24, 17 November 2023 (UTC)

I broadly agree with your reasoning. Johnjbarton (talk) 18:24, 17 November 2023 (UTC)

The math is simple but the implications are purely theoretical because we are talking about things which are mathematical concepts rather than reality. For example, an electron and a proton at rest are textbook ideas. Bill field pulse (talk) 20:04, 16 January 2024 (UTC)

I disagrgee with such statement.

An electron at rest is as much a textbook idea as is a car at rest. 2A02:B98:4736:AC7C:F537:BE3F:7366:C530 (talk) 17:51, 24 January 2024 (UTC)

Thank you for pointing out this issue 2A02. Do you agree that in an atom they cannot be at rest because the field from a Proton is actually a field made by quarks cycling at near the speed of light? So the most likely place for an electron to be at rest is in a surplus of electrons in say a metal ball which is at rest. Do you agree that the fields of all the other balanced electrons in all the atoms in the ball are in a constant state of motion due to electrons moving in their orbitals. What happens to your perfectly spread out surplus electrons as they sit in these volatile EM fields in all the atoms. surely they must react to all the vibrations and field changes all around them. I would argue strongly that you can have a large number of electrons which have a net charge which is perfectly at rest. But at the atomic level there is so much activity even in a cold hard metal ball that it is impossible to hold an individual electron still. Only for an infinitely short instant is an individual electron truly at rest. I would appreciate more from you regarding the condition you have in mind where a single electron is at rest. However, if you agree that only a large number of electrons can have a net charge which is at rest then yes we are on the same page. Bill field pulse (talk) 21:14, 24 January 2024 (UTC)

Any relation?

In a recent edit a user named @Lekner added this ref:

• Lekner, J. (2021). [DOI: https://doi.org/10.1063/9780735423350 Electrostatics of conducting cylinders and spheres]. Melville, NY: AIP Publishing. ISBN 978-0-7354-2335-0. {{cite book}}: Check |url= value (help)

Please be aware of Wikipedia's Conflict of interest policy. Johnjbarton (talk) 03:22, 17 June 2024 (UTC)

It also turns out that almost all of the contributions by @Lekner consist of additions of references to works by J. Lekner. Johnjbarton (talk) 03:25, 17 June 2024 (UTC)

All reverted. A warning was left on the user's talk page. Constant314 (talk) 04:24, 17 June 2024 (UTC)