Talk:Pendulum/Archive 4

Sumerian culture
An editor recently added a reference to the Sumerian culture having developed a one-second pendulum some 5000 years ago. Is this a "Fringe Theory", a hoax, a coincidence or a forgotten art? It is certainly not mainstream thought? Does anybody else know anything about this statement, and if so, should it be prefixed with "Certain archeologists are of the opinion that ...". Martinvl (talk) 20:48, 26 September 2013 (UTC)
 * Sounds highly dubious to me. --Roly (talk) 21:18, 26 September 2013 (UTC)
 * This is amateur numerology. I found one book online which contains the theory:  Christopher Knight, Alan Butler (2004) Civilization One: The World Is Not as You Thought It Was.  I would not call it a RS, it is in the category of Graham Hancock-style fringe archaeology, advancing the theory, based on numerical coincidences, that megalithic civilizations were super-advanced technologically.  Neither in this source nor the Roland Boucher paper is there any reference to this stuff being published in a peer-reviewed journal.  I think the sentence has to go. -- Chetvorno TALK 01:22, 27 September 2013 (UTC)
 * I will remove it. Martinvl (talk) 03:06, 27 September 2013 (UTC)

Change to sentence in introduction
I am concerned about a recent change to a sentence in the introduction, from:
 * "A pendulum swings with a specific period which depends (mainly) on its length."

to
 * "If the amplitude of the oscillation is small, a pendulum swings with a specific period which depends on its length."

The new sentence is attempting to take account of the fact that at large amplitudes the period is dependent on the amplitude as well as the length. However I feel this can be misleading for the general readers who will be reading the introduction. The new sentence gives the erroneous implication that at large amplitudes the period is not dependent on length. The fact is that the length of the pendulum is the main determinant of its period at all amplitudes; the amplitude only has a small effect over most of the range. We already have an extensive explanation of the effect of amplitude in the next section. I feel the original sentence was clearer. -- Chetvorno TALK 00:13, 18 December 2013 (UTC)
 * Does the latest change work for you? DOwenWilliams (talk) 04:22, 18 December 2013 (UTC)
 * Thanks for asking. I really feel that the amplitude dependence is an unimportant, confusing technical detail which does not belong in the introduction.  If we are going to add to the introduction, there are many more notable facts about pendulums which could be added.  The previous statement - that the pendulum's period depends mainly on its length - was a good generalization for introductory readers.    However your changes do remove the misleading implications I mentioned, and I can live with the current text. -- Chetvorno TALK 20:36, 18 December 2013 (UTC)
 * I think the introductuon sould include a mention of the fact that the oscillation period is usually determined by the length of the pendulum, and not by the amplitude, since this is the basis of the use of the pendulum in clocks, but that there is a caveat that the amplitude must be small. Pendulums that swing 60 degrees, say, from the vertical are no good in clocks. (I have witnessed kids trying pendulums with wide swings, and their puzzlement when they didn't keep good time.) The problem is how to summarize this in a sentence or two in the lead of the article. DOwenWilliams (talk) 03:48, 19 December 2013 (UTC)

Pendula were never guillotines
The last paragraph of the article needs to be removed. No responsible historian actually thinks that pendula were ever used as torture devices outside of Edgar Allen Poe novels. The "main article" that is linked says as much (between the lines). British Protestant propaganda about the Spanish inquisition is not to be trusted in such matters. It is unworthy of wikipedia to repeat such ancient canards. Dlw20070716 (talk) 10:49, 17 August 2015 (UTC)

Also, the picture of the "pendulum" in the Metropolitan Cathedral, Mexico City ought also to be removed as it's actually a plumb bob, not a pendulum. (It's purpose is not to swing, but rather to point out the tilt of the Cathedral.) Dlw20070716 (talk) 11:11, 17 August 2015 (UTC)

Semi-protected edit request on 7 June 2016
In Section "1673: Huygens' Horologium Oscillatorium", 1st para., last sentence: Change "solved the issue" to "solved the problem". Reason: Replace Microsoft euphemism "issue" with what it really means.


 * ❌ a search for "issue" in the article gives no matches - and it hasn't been removed recently either - Arjayay (talk) 07:39, 8 June 2016 (UTC)

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Movement is inherently distracting to the eye. All Wikipedia animations should be optional. They are great to have and it's fine to run them by default, but there must be a simple way to disable them.Propanscience (talk) 16:42, 12 July 2016 (UTC)

The arithmetic-geometric formula again
The "Period of oscillation" section gives the series expansion for the true (large angle) period of the pendulum
 * $$\begin{alignat}{2}

T & = 2\pi \sqrt{L\over g} \left( 1+ \frac{1}{16}\theta_0^2 + \frac{11}{3072}\theta_0^4 + \cdots \right) \qquad\qquad (1) \end{alignat}$$ A second formula for the true period has recently been added by User:J20160628
 * $$T = \frac{2\pi}{M(\cos(\theta_0/2))} \sqrt\frac{L}{g} \qquad\qquad\qquad (2)  $$

where $$M(x)$$ is the arithmetic-geometric mean of 1 and $$x$$.

The addition of this formula to the article has already been thoroughly discussed on this Talk page; see Which formula for the true period should be used? above. The consensus of at least 5 editors (Zueignung, Maschen, Crowsnest, Martinvl and myself) was that it should not be added, for these reasons: For these reasons I think the second formula should be removed. -- Chetvorno TALK 19:18, 3 July 2016 (UTC)
 * This article is already huge and bloated. We have a separate article for the mathematics of pendulums: Pendulum (mathematics).  The formula is already given there, which is the appropriate place for it.
 * The inclusion of the series formula (1), the traditional formula for the large angle period, is important for historical reasons; it shows where the small-angle formula $$T = 2\pi \sqrt{L/g}$$ comes from, and it is referred to in the text, while the new formula is not.
 * The description of the second formula (2) as "exact" and "error-free" is wrong; the arithmetic-geometric_mean M(x) needed to calculate it must itself be calculated iteratively from an infinite series. At some point this calculation must be terminated, leaving an error.    There are no "exact" (closed form) formulas for the large angle period of a pendulum.  The only advantage of the second formula is that it is faster converging.
 * I fully agree. As mentioned by Chetvorno, the matter has already been discussed before, with the consensus to remove it. -- Crowsnest (talk) 20:35, 4 July 2016 (UTC)


 * I think that the first formula must be removed as outdated, only linearly convergent and error correction requiring for large oscillations. The second formula is quadratically convergent. Chetverno is entirely wrong in thinking that the second is equivalent to the first since he keeps expanding the second into power series which MUST BE AVOIDED. In fact, Gauss then in 1799 discovered a novel and an absolutely superb way of calculating complete elliptic integrals. The time has come for the masses to understand that. Here is an understandable reference for non mathematicians http://www.cse.unsw.edu.au/~en1811/12s2/assigns/assign2/ass2_pend.html. — Preceding unsigned comment added by 114.147.68.146 (talk) 08:21, 5 July 2016 (UTC)
 * This is not an article on mathematical methods for solving the pendulum. We have that, it's called Pendulum (mathematics), and it already discusses the formula (2).  This is a general article on the pendulum, and the formula you are pushing is nowhere near WP:NOTABLE enough to be included. This has already been thoroughly discussed here.  Wikipedia is not a WP:SOAPBOX for you to push your favorite math formulas on the "masses";   please read WP:Righting Great Wrongs. -- Chetvorno TALK 07:11, 6 July 2016 (UTC)

I applaud the brilliant idea of 114.147.68.146. Certainly, outdated material must be removed from this blunted article to archives or elsewhere. I have researched the exact and fast period formula and found primary, secondary and tertiary material to support it, so whoever keeps arguing against it better keep their views to themselves. I can find many interesting views already presented on this talk page, which was apparently ignored by pseudoscientists who Chetvorno has led instead of refuting them as he claims to do on his talk page. So, I hope he converts his efforts to humbly serve the truth.Highness 11:00, 7 July 2016 (UTC) — Preceding unsigned comment added by J20160628 (talk • contribs)


 * The method is indeed useful, but it is an iterative method, not a formula in the strict sense. Thus it belongs in the mathematical article, not here in the general article.  This has been discussed at length in the past, and I see no reason to change the agreed policy.  Why should I keep my views to myself?     D b f i r s   12:01, 7 July 2016 (UTC)


 * Indeed, the question is not whether the AGM method is useful to compute the elliptic integral appearing in the "exact" pendulum period. Although (because of the foregoing) not of any relevance anymore for this article, the Adlaj references are not often cited by others and of undue weight for Wikipedia purposes – an earlier and better reference for the nonlinear pendulum period and the use of the AGM to compute the elliptic integrals would be pages 1–15 of Borwein & Borwein (1987) Pi and the AGM, Wiley. -- Crowsnest (talk) 18:38, 7 July 2016 (UTC)


 * Excuse me,, are you the same person as 114.147.68.146? It is fairly suspicious that 114.147.68.146 is a new account that has made only 2 edits, one on this Talk page.  The only other person who has pushed this formula, during the previous discussion, was a single disruptive editor who used the sockpuppets  Syrmath, SupremeFormula, and 193.233.212.18, and was permanently blocked.  Are you also the same person that used these usernames?  If so, I don't have to tell you that an editor using multiple usernames to disguise his identity, called sockpuppeting, is prohibited on Wikipedia and can get you blocked. -- Chetvorno TALK 19:48, 7 July 2016 (UTC)

(Personal attack removed) Blocking the most competent editors is a shame. It explains why 114.147.68.146 is the only one who's left. (Personal attack removed) Ignoring, deleting and denying seem to be the only tools available to them. Reasoning seems to anger them. What a pity. Highness 15:30, 9 July 2016 (UTC) — Preceding unsigned comment added by J20160628 (talk • contribs)


 * User:J20160628 has been blocked as a sockpuppet. -- Chetvorno TALK 13:33, 29 December 2016 (UTC)

Semi-protected edit request on 25 January 2017
203.202.240.50 (talk) 06:49, 25 January 2017 (UTC) yuo7899i
 * Red question icon with gradient background.svg Not done: it's not clear what changes you want to be made. Please mention the specific changes in a "change X to Y" format. DRAGON BOOSTER   ★  06:50, 25 January 2017 (UTC)

Temperature Compensation
The maths seems to be incorrect in the sentence:

"A pendulum with a steel rod will expand by about 11.3 parts per million (ppm) with each degree Celsius increase (6.3 ppm/°F), causing it to lose about 0.27 seconds per day, or 16 seconds per day for a 33 °C (60 °F) change."

(unless my brain is more confused than normal). Which figures are the correct ones? Roly (talk) 11:46, 4 January 2013 (UTC)

Same here in the Invar paragraph:

"This has a CTE of around 0.5 µin/(in·°F), resulting in pendulum temperature errors over 71 °F of only 1.3 seconds per day"

Is my maths ability really that much up the spout? Roly (talk) 14:03, 4 January 2013 (UTC)


 * The maths is incorrect - somebody got confused between degrees Celsius and degrees Fahrenheit when they bolted on the second half. I have reworded it. Martinvl (talk) 15:17, 4 January 2013 (UTC)

The reference [83] to Matthys concerning the supposed tendency of the gridiron pendulum to move in jumps should be removed along with the statement itself until a definitive reference can be identified. Matthys merely repeats the assertion with no evidence or authoritative reference. Thomas Reid in his 'Treatise on Watch and Clockmaking - Theoretical and Practical' writing in 1848 when gridiron pendulums were state-of-the-art does not mention such a tendency. Rees' Cyclopedia also makes no mention of this motion being in jumps.Peter R Hastings (talk) 21:54, 2 March 2017 (UTC)
 * Matthys is a fairly authoritative source. There are many other statements in this article whose supporting sources give "no evidence or authoritative reference".    The temporary rate deviations due to the friction induced jumps is only significant in precision astronomical regulators used for high accuracy scientific work, so it might not be mentioned in a general encyclopedia or a clock treatise such as Reid.  Alternatively, it may not have been recognized until the end of the 19th century, when a lot of research on clock accuracy was done, which would have been after the Reid and Rees sources were published. -- Chetvorno <i style="color:purple; font-size:smaller;">TALK</i> 22:41, 2 March 2017 (UTC)

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Vandalism
Can we get this article protected, please? I have raised a request.--Roly (talk) 20:07, 31 August 2017 (UTC)

Nonsense
The article states "Pendulum clocks should be attached firmly to a sturdy wall." This is patent nonsense,very many pendulum clocks are free standing, including the mantel clocks mentioned in the following paragraph. Stub Mandrel (talk) 06:45, 1 April 2021 (UTC)
 * It's not nonsense. For best accuracy, it's true. --Roly (talk) 08:47, 1 April 2021 (UTC)

Sorry Roly, but a blanket statement that pendulum clocks SHOULD be attached to a sturdy wall is clearly not true.In fact the most accurate pendulum clocks are mounted on isolated high-mass bases, not on walls. I will edit again. Stub Mandrel (talk) 17:56, 10 April 2021 (UTC)

Simple pendulum
Explain the simple pendulum 160.238.74.181 (talk) 16:54, 20 March 2022 (UTC)


 * Read the article.  Velella  Velella Talk 17:14, 20 March 2022 (UTC)

Physics
What is simple pendulum 103.26.83.140 (talk) 08:04, 7 June 2022 (UTC)

mention Fedchenko prrecision pendulum clock?
Along with Shortt and Riefler precision pendulum clcoks, perhaps the Fedchenko clock deserves mentioning?

Although the article is long, something about the fundamental limit to timekeeping with a pendulum, i.e. tidal variations in gravity, would be nice. — Preceding unsigned comment added by 87.100.175.140 (talk) 11:25, 1 January 2017 (UTC)


 * The article seems to imply that atmospheric variations are more significant than tidal effects. Do you have a reference that compares these.  We don't even have an article on Feodsii Michailovich Fedchenko (yet).    D b f i r s   17:38, 1 January 2017 (UTC)
 * A reference in the open literature is given here: https://hgss.copernicus.org/articles/11/215/2020/
 * Agnew, D. C.: Time and tide: pendulum clocks and gravity tides, Hist. Geo Space. Sci., 11, 215–224, https://doi.org/10.5194/hgss-11-215-2020, 2020.
 * There are also papers in Horological Science News by T Van Baak including stability charts for clocks influenced by barometric variations and tides that clearly show an order of magnitide or more greater influence of the former. So tides are the limiting factor.  One of these papers also shows that one of the Fedchenko clocks clearly tracked tidal gravity fluctuations.  http://leapsecond.com/hsn2006/ 2A00:23C7:D613:5901:6D47:CD87:3903:D342 (talk) 13:39, 18 April 2023 (UTC)

Relationship between the period of a pendulum and the length of the string
Relationship between the period of a pendulum and the length of the string 103.75.21.254 (talk) 03:33, 20 September 2023 (UTC)