Talk:Electrostatics/Archive 1

Archive 1

Untitled

Is liquid accumulator below 50 pico Siemens /cm or 50 pico Siemens / m ?

this article is really difficult for me to understand! perhaps someone who already does understand electrostatics could give a clearer "big picture". thanks!

Justanyone wrote in the edit summary: Initial version here. Just tried to describe that this was an abstract term that could mean 2 things

Not in my textbook it can't. References? -- Tim Starling 07:43, Nov 16, 2003 (UTC)

vandalism removed from article and talk page. c'mon - grow up. May 5, 2004

That whole crap at the start with the triangle and those other equations. What the hell does any of that mean? We're not all freakin physicists. Explain this stuff in a way 99% of us can understand.

I removed a section on charge generation that was a duplicate of the electrostatic generator section. "The presence of surface charge imbalance means that the objects will show attractive or repulsive forces. This surface charge imbalance, which leads to static electricity, can be generated by touching two differing surfaces together and then separating the objects due to the phenomena of contact electrification and the triboelectric effect. Rubbing two non-conductive objects generates a great amount of static electricity. This isn't just the result of friction; two non-conductive surfaces can become charged by just being placed one on top of the other. Since many surfaces have a rough texture, it takes longer to achieve charging through contact than through rubbing. Rubbing objects together increases amount of adhesive contact between the two surfaces. Usually insulators, i.e., substances that do not conduct electricity, are good at both generating, and holding, a surface charge. Some examples of these substances are rubber, plastic, glass, and pith. Conductive objects only rarely generate charge imbalance except, for example, when a metal surface is impacted by solid or liquid nonconductors. The charge that is transferred during contact electrification is stored on the surface of each object. Static electric generators, devices which produce very high voltage at very low current (such as the Van de Graaf generator or Wimshurst machine) and used for classroom physics demonstrations, rely on this effect.

Note that the presence of electric current does not detract from the electrostatic forces nor from the sparking, from the corona discharge, or other phenomena. Both phenomena can exist simultaneously in the same system."''

Also, really, it's an article that can be understood on many different levels - as all physics is. The guy with the PhD who can't understand it needs to do some more reading outside his 'science' field. I'm a high school physics student and really, its not that difficult. —The preceding unsigned comment was added by Bochum (talk • contribs) 08:28, April 7, 2007 (UTC).

Bochum, you're missing the point. If an information-rich Wikipedia article can only be understood by someone who has read another information-rich source like a physics text book, then that article is failing. I'm all for maintaining high standards in Wikipedia science articles, but the first part of the article has to be as accessible as possible: I'd suggest that it must, in layman's terms, explain what the article is about, where the subject of the article is found or occurs, and why it is of importance. Since (I would imagine) most people will come to the article seeking information on static electricity then that should be the beginning of the article.

If you think someone curious about why a balloon sticks to the ceiling will learn anything from Electrostatics is the branch of physics that deals with the forces exerted by a static (i.e. unchanging) electric field upon charged objects, then you must hang around with some very smart people!

Imagine if I started an article on something I've published on by starting the very first line on ammonites with:

• Non-segmented coelomate bilaterians with external, usually exogastrically coiled, shells that are biostratigraphically distributed from the Middle Pragian to Late Maastrichtian and believed to be the immediate sister group of the Coleoidea within the Neocephalopoda.

Completely accurate, but not very helpful compared with saying:

• Ammonites are molluscs with external shells that are usually coiled above the body and are found from the Devonian to Cretaceous periods and are believed to be closely related to the living squids and octopuses.

So don't be snotty, and try and understand why this article needs help, and put your expertise into doing exactly that. Cheers, Neale Neale Monks 11:53, 7 April 2007 (UTC)

Thank you for your input. I have added a clearer introduction for the layman that should make it more accessible to the general population e.g. those of us who haven't had a physics lesson before. I haven't changed the rest of the article as it seems to be that the introduction was the part causing all the fuss. The part on electrostatic charge generation is fairly clear. Also, I don't think that it should be necessary in a Wikipedia article to explain everything from the bottom up and there must be an assumption of at least some minimal prior knowledge. Your example on ammonites was different - this sentence assumed large prior knowledge. However, I agree that an introduction was necessary. Why it needed a high school student to introduce one I am not entirely clear on...Bochum

REdir from static electricity

Static electricity has been redirected here. Original Material still exists on static electricity page--Light current 00:59, 22 October 2005 (UTC)]]

Reference section?

Umm ... the "block msg" as a reference, is it necesssary? I removed it ... JDR. Hmm ... why was the "Book reference" template giving me a block msg? Funky ... nothing to see here ... move along ... JDR go to fucking hell you science weirdos you guys spend your time discussing shit that in tbe end it will not matter. you are just wasting your time. Life is too short.

Thank you for your comments; they have been duly noted and action will be taken when we have a spare moment from applying our science in pratical ways that stop you dying, earning much money from doing so. Enjoy your little life. 57.66.51.165 09:01, 29 March 2006 (UTC)

This article cannot explain how static electricity works clearly. It needs simple explanation for children and students. I must say this is rubbish.

Needs work!

I'm a scientist with a PhD and a BSc and I have no idea what this article is about. It may make sense to physicists, but without at least an introductory chapter (i.e., What is static electricity) its next to useless otherwise. Besides an introduction, it needs to have some historical background. For example: amber and electricity; electrical research based on static electricity not current electricity before the battery; why static electricity develops on household items like fabric; why static makes things stick together (balloons to ceilings for example); connections (if any) with natural phenomena such as lightning.

Cheers, Neale Neale Monks 11:11, 30 March 2007 (UTC)

Huh?

I'm probably echoing a sentiment already voiced here, but I just read the static electricity section, and I understood almost none of it. I think Static electricity should be split into its own article and explained in detail and with less scientific jargon. It is certainly noteworthy enough. I volunteer to help with the article if someone takes the initiative and starts it. Let me know. Paul Haymon 02:40, 1 April 2007 (UTC)

What about splitting the topic out?

Perhaps two separate articles could be created -- one regarding the everyday experiences that one has, and another related to formal physics, as the current one is. They could be discerned through disambiguation. I am an amateur at physics, yet I find the highly technical articles, such as this, an *extremely* helpful resource, because they are not "dumbed-down" like so many other resources, both web and traditional. Furthermore, the depth of some of these articles is hard to match outside of a textbook, in some cases. 68.211.50.163 03:12, 8 June 2007 (UTC)

Definition too narrow & unnecessary equations

I think the article can be greatly improved.

Tha article is too light in physical ideas and too heavy in the math. I would leave the math as links to the math sections of wikipedia.

1) The explanations are not rigourous enough, The current definition focuses too much on dielectric objects and forces, but actually electrostatics deals with a wider variety of phenomena. There's a big chunk of electrostatics literature that deals with charged conductors. In many practical problems the electric potentials are the quantities of interest rather than the forces. Actually the physics of charge distributions in conductors are simpler, because there's no need to deal with concepts like dielectric displacement.

The "dielectrics and forces" theme is how the research started and is what people teach in high-school but it's quite a distortion from the actual field of electrostatics.

b) I think the partial differential equations should be cited but should not be included. The intended audience is someone who doesn't know electrostatics already, probably a non-physicist. Including the PDE's will not give much insight into the phenomena in question. It will suffice to say that in many electrostatic problems the fields satisfy those equations and put a link to them. Also the equations will take different forms depending on the system of units used, which can cause confusion even for scientists. Converting electrostatic equations from c.g.s (electrostatic version, also called Gaussian) to S.I. is particularly tricky if you are not familiar with the subtleties is not just a matter of multiplying by conversion factors, some of the basic definitions are different. Unfortunaley you find both systems in many papers, sometimes they don't mention which one they are using.

Here's a good explanation of the c.g.s vs S.I problem. [1]

Also, to emphazise the importance of the topic I would also include non-trivial applications of electrostatics like capacitors, electrostatic dissipative materials. It might be nice to mention there are similarities of the equations of electrostatics with those governing other phenomena like heat transfer or charge transport, so if you understand electrostatics you can also solve these other problems.

Condensor Voltage

In a Physics book I saw a drawing of 2 condensors connected in parallel to a battery One has no dielectric between the plates (air)( ~ 1 dielectric constant) The other has a dielectric whatever ( dielectric constant > 1)

Then 2 drawings : a voltmeter connected to each condensor (separated now) The following statement (from the book) clashes with all my "knowledge" of electricity: The voltmeter connected to the condensor without dielectic(air)shows a voltage HIGHER than the other

My question: How did the voltage become different if the assembly was charged and then all was disconnected . ?

If it was done one by one (I mean charging one at a time the mesured voltage would be equal to the battery voltage , providing the voltmeter was like an electrometer (internal resistance infinity)

I know the charge (Coulombs) would be different but the VOLTAGE ???????

Any answer to this ??? —Preceding unsigned comment added by Gsbr (talk • contribs) 09:20, 22 September 2007 (UTC)

Polarization in the dielectric creates a field which opposes the applied field, reducing the measured voltage. The polarization density (electric dipole moment per unit volume) is given by:

$\mathbf {P} =\epsilon _{0}(\kappa -1)\mathbf {E}$,

where $\scriptstyle {\kappa }$ ($\scriptstyle {\geq 1}$) is the dielectric constant and $\scriptstyle {\mathbf {E} }$ is the applied electric field. Clearly polarization only occurs for $\scriptstyle {\kappa >1}$, hence the presence of the dielectric reduces the voltage.DJIndica 04:39, 5 November 2007 (UTC)

Template:Electromagnetism vs Template:Electromagnetism2

I have thought for a while that the electromagnetism template is too long. I feel it gives a better overview of the subject if all of the main topics can be seen together. I created a new template and gave an explanation on the old (i.e. current) template talk page, however I don't think many people are watching that page.

I have modified this article to demonstrate the new template and I would appreciate people's thoughts on it: constructive criticism, arguments for or against the change, suggestions for different layouts, etc.DJIndica 04:03, 5 November 2007 (UTC)

To see an example of a similar template style, check out Template:Thermodynamic_equations. This example expands the sublist associated with the main topic article currently being viewed, then has a separate template for each main topic once you are viewing articles within that topic. My personal preference (at least for electromagnetism) would be to remain with just one template and expand the main topic sublist for all articles associated with that topic.DJIndica 04:14, 5 November 2007 (UTC)

Split Page into 'Electrostatics' and 'Static Electricity'

In reponse to much of the recent talk about the 'too technical' nature of this page, I propose that the article be split into two.

One, titled 'Static Electricity', would revolve around the human experience of static electricity, (cat's fur and glass rods, static 'shock' when rubbing shoes on carpets, etc) and would be written with a very general audience in mind. This article would serve as an 'access point' for the general public, and have links to the more formally 'scientific' theories, expressions and phenomena as appropriate. It is my hope that such a page would not 'hide' the 'real science' from the casual reader, but be the bridge that allows them to connect their daily experiences with a more formal discussion.

The second page, entitled 'Electrostatics' would concern electrostatic theory at the level that it is usually presented in an undergraduate science course. This page would include much of the current content, but would benefit from a notably clearer purpose.

I believe that two shorter articles with clear purposes would be a marked improvement over the current situation. Thoughts? Supasheep 21:31, 8 November 2007 (UTC)

Agree Two levels of explanation with links to each other is a good idea. Binksternet 03:03, 9 November 2007 (UTC)

I have started an article on static electricity on my user subpage which I will soon move to the main article space. Comments and suggestions are welcome, feel free to edit the page. --DJIndica (talk) 19:37, 20 January 2008 (UTC)

The article is up, see Static electricity. --DJIndica (talk) 12:54, 21 January 2008 (UTC)

language

sorry for my bad english... --Pediadeep (talk) 21:14, 11 April 2008 (UTC)

Error in the Flux figure

The figure showing the flux lines with the conductors is not correct. This figure shows flux lines coming out of a conductor and then entering the same conductor at a different point on the surface. This cannot happen in electrostatics. The entire conductor is at the same potential (voltage) and hence flux lines cannot leave and enter the same conductor. Elee1l5 (talk) 19:52, 19 February 2013 (UTC)

Thanks a lot for catching my mistake, Elee115. I corrected the drawing. Whew, I don't know what I was thinking. --Chetvorno^TALK 04:10, 29 June 2013 (UTC)

Thanks for the correction! Elee1l5 (talk) 20:30, 5 July 2013 (UTC)

"Coulomb's law": who is k₀?

"The use of ε₀ instead of k₀ in expressing Coulomb's Law is"... — but what is meant by k₀? maybe k_e? Boris Tsirelson (talk) 15:29, 30 March 2014 (UTC)

External links modified

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Theorem of corresponding elements, Coupling matrix, Self and Mutual capacitance, coupling coefficient

I propose to add these elements in new sections. The theorem of corresponding elements is well known in France but seems not very popular elsewhere (I found only three ref in .edu English pages), but this is not a critical input. The other subjects are far more important and are present in any serious electrostatics course. They can also be introduced in the Capacitive coupling page that presently only discuss the degenerate case of total influence corresponding to a coupling coefficient of unity (in this case the degenerated matrix that normally involves three coefficients is replaced by an approximation involving a single coefficient leading to the usual capacitor). To say it otherwise the present capacitive coupling page only introduces the very special case $k_{C}=1$. Maybe the Electrostatic page can stop to the matrix description after the introduction of the self and mutual capacitance coefficients. The capacitive coupling page can go a bit further by introducing the capacitive coupling coefficient and optionally the two possible points of view; matrix: $k_{C}={\frac {C_{m}}{\sqrt {C_{1}C_{2}}}}.$ or circuits: $k_{C}={\frac {C_{m}}{\sqrt {(C_{1}+C_{m})(C_{2}+C_{m})}}}.$. This may help to clear the asymmetrical aspect that you presently have in the Coupling coefficient of resonators page (formula (5)-(7)), these formulas are not really incorrect but need to introduce a specific point of view that is not straightforward (the usual direct matrix approach leads to a symmetrical aspect for both couplings). Besides the "pi" model and the duality with the magnetic induction coupling between dipoles could also be introduced. What do you think ? --Henri BONDAR (talk) 20:26, 28 February 2016 (UTC)

I think that the Capacitive coupling page would be the most appropriate page. Constant314 (talk) 00:18, 29 February 2016 (UTC)

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Spontaneous explosion of grain silos

The lede of this article mentions that electrostatic phenomena include "spontaneous explosion of grain silos" but disappointingly doesn't return to this intriguing point. Can we expand a bit on this point, or at least link to an article with more information? If the latter, is dust explosion the right article? – Arms & Hearts (talk) 16:49, 9 September 2020 (UTC)

cat

i love that cat 172.58.46.224 (talk) 19:00, 19 April 2022 (UTC)

physics

what's electrostatic 2400:ADCC:11D:B300:F51B:A9EE:9922:551D (talk) 15:57, 5 October 2022 (UTC)

Static-Cat, jpg or png

There seems to be a battle started of the cat image. My understanding is that png is preferred, but the png version states that is is User Badoomm's own work, while it appears to be an unattributed derivative work. If we can sort that out, I see no reason to not use the png version. Constant314 (talk) 04:15, 3 January 2020 (UTC)

This image of a cat on this otherwise professional page offends me, and I am very angry. — Preceding unsigned comment added by 2603:3005:1400:1600:84D4:A7DA:5999:73E1 (talk) 08:37, 20 January 2020 (UTC)

What is it that makes you angry about it? --Chetvorno^TALK 16:14, 20 January 2020 (UTC)

Does anyone else have an opinion on the appropriateness of the cat picture? We are discussing a similar issue on the electric field talk page.Footlessmouse (talk) 20:51, 13 August 2020 (UTC)

I think that it is great. Constant314 (talk) 21:59, 13 August 2020 (UTC)

+1 for Lolcats!

I think it is appropriate, where the internet has both suitable and unsuitable images of animals. For example dressing a pet in a costume, probably is awkward, but, in the grand scheme of things is quite harmless, certainly less harmful than leaving your pet without stimulus, which is traumatic.

I think it is a clearly useful example, and analogy, to be able to say look at this animal experimentation, that is okay for it to have been done. Therefore it allows us to criticise genuine animal abuse and say "that is not even funny", just like for example an animal in a costume, is by extension a good example, even if you or I never dressed up our pets in matching Pokémon costumes.

Signed - Meowth of Team Rocket. — Preceding unsigned comment added by 49.184.195.195 (talk) 00:47, 6 May 2022 (UTC)

Electrostatics Definition vs examples

The definition given is the study of "Slow moving or stationary charges".

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) 22:06, 15 January 2024 (UTC)

This is a duplicate of the #Partial section above, can we please not duplicate. Ldm1954 (talk) 22:40, 15 January 2024 (UTC)

Sorry about that. I will move it above Bill field pulse (talk) 16:19, 16 January 2024 (UTC)

How can k₀ and ε₀ both be exact?

The article claims that ε₀ and k₀ are both defined exactly, giving the former as 8.854 187 817 × 10⁻¹² and the latter as (apparently) the integer 8,987,551,787. However the former should be the reciprocal of (the latter times 4π) which would make its mantissa 8.854 187 817 983 1...

So which of those two constants is the exact value? (I have my fingers crossed for k₀.) Vaughan Pratt (talk) 18:20, 18 December 2020 (UTC)

Ok, it turns out that k₀ is exactly c²/10⁷ = 8987551787.3681764. (That is not an approximation, it is an exact rational!) So ε₀ is also exact but is irrational, in fact transcendental, namely 1/(4πk₀) ~ 8.854 187 817 620 389 850 536 563 031 71... × 10⁻¹².

I'll let this settle before actually doing anything about it in the article itself. Vaughan Pratt (talk) 19:58, 18 December 2020 (UTC)

@Vaughan Pratt: Neither is: cf. Coulomb's law#Coulomb's constant. Ponor (talk) 20:08, 18 December 2020 (UTC)