Talk:Kilogram/Archive 8

Image description on Commons
The image Commons:File:Watt balance, large view.jpg, used in this article, was uploaded in 2007, and the description is out of date (e.g. "Currently the primary standard defining all the world's mass and weight units is the International Prototype Kilogram"). Because of the amount of detail in the description, it can't be fixed by simply changing from future tense to present. As the file talk page on Commons is unlikely to be watched, I'm asking here if somebody with the requisite knowledge can update the description. 2001:BB6:4713:4858:7DCC:1F54:AB7A:19CD (talk) 09:58, 16 September 2021 (UTC)

Moved "at the temperature of its maximum density" in the timeline back to 1799
I moved the statement "It had a mass equal to the mass of 1 dm3 of water at the temperature of its maximum density, which is approximately 4 °C" in the timeline back to 1799 (diff). Some time ago an editor accidentally moved it to 1875 (diff). In addition I removed "under atmospheric pressure", because it actually was the weight in vacuum. Ceinturion (talk) 14:04, 19 October 2021 (UTC)

Change Picture to Kibble Balance
I propose adding a picture of a Kibble balance because the kilogram is now defined not by a block of metal but by a fundamental constant of nature, the Planck constant. I would like to either replace the picture in the lead with https://upload.wikimedia.org/wikipedia/commons/5/57/Nist-4.jpg or add it somewhere in the article. ScientistBuilder (talk) 14:31, 18 February 2022 (UTC)
 * In my eyes, the image of the Kibble balance is useless for this kilogram article. The photo does not clarify anything, except that the Kibble balance contains a lot of scrap metal. Ceinturion (talk) 16:33, 18 February 2022 (UTC)


 * I agree with the inclusion of the picture of the Kibble balance (although I note the article already has an older one), but I don't think it would be especially useful in the lede. For one thing, anyone who has heard of a Kibble balance is already familiar enough with the concept of the kilogram that a Wikipedia article can likely do little to educate them further. For another, while it's obviously directly relevant to the article's subject, it's not a very useful visual representation of a kilogram. An old-school hexagonal weight is a form that most people are much more likely to find relatable. Likewise, our article on the second doesn't try to depict "the time duration of 9 192  631  770 periods of the radiation corresponding to the transition between the two hyperfine levels of the fundamental unperturbed ground-state of the caesium-133 atom" literally (or the apparatus that might be used to measure such a quantity); it depicts something that people would naturally find much easier to relate to as a means of measuring a unit of time. Archon 2488 (talk) 18:13, 18 February 2022 (UTC)
 * I changed the picture from a bronze piece of metal to the International Prototype Kilogram. ScientistBuilder (talk) 00:40, 23 February 2022 (UTC)

"Defining constant"
that the defining constant of the kilogram is the Planck constant is incorrect. I don't think this sort of information detail belongs in the infobox at all. 172.82.47.242 (talk) 23:29, 3 September 2022 (UTC)

Misleading Definition
BrianFennell (talk) 18:48, 9 February 2023 (UTC)
 * In the "Definition" section
 * c is the speed of light, but has nothing to do with the meter in the context of defining the kg
 * Instead
 * Planck constant
 * Planck's constant [ . . . ] gives the relationship between the energy of a photon and its frequency, and by the mass-energy equivalence, the relationship between mass and frequency. [ . . . ] a photon's energy is equal to its frequency multiplied by the Planck constant.
 * Mass%E2%80%93energy_equivalence
 * [ . . . ] removing energy is the same as removing mass and the formula m = E/c2 [ E divided by c squared ] indicates how much mass is lost when energy is removed [ . . . ] The Planck-Einstein relation for the energy for photons is given by the equation E = hf, where h is the Planck constant and f is the photon frequency.
 * so . . . h times delta V caesium is equal to a very small but specific amount of energy.
 * E / c2 gives a very small but specific amount of mass (by mass-energy equivalence)
 * (big number) times E / c2 gives exactly one kg of mass.
 * Units
 * h has units of J times Hz (to the) -1 "Planck constant is expressed in SI units, it has the exact value h = 6.62607015×10−34 J⋅Hz−1"
 * delta V caesium has units of Hz. ( Isotopes_of_caesium ))
 * h times delta V caesium has units of J ( Joule )
 * so . ..
 * The Definition section should be changed to reflect this
 * I don't follow you. Please provide the wording you think the article should use. I think the formal definition from CIPM must stay, because it truly is the SI definition of the kilogram. The rest of the section is supposed to help the reader understand the formal definition. -Arch dude (talk) 01:21, 10 February 2023 (UTC)

Should "Kilo" redirect here?
Please comment at Talk:Kilo. fgnievinski (talk) 21:12, 28 April 2023 (UTC)

The entire "Kilogram becoming a base unit: the role of units for electromagnetism" should be moved to another article.
Before we try for GA status, this section should be removed. It is not about the Kilogram at all. It's about an earlier version of the metric system. -Arch dude (talk) 14:00, 14 July 2023 (UTC)

OK, I'm moving the entire mess to Draft:Kilogram in the Giorgi system. I hope to eventually incorporate any salvageable parts into one of Metric system, Outline of the metric system, or History of the metric system, but frankly it is so poorly written and referenced that I have little hope for it. -Arch dude (talk) 19:34, 18 July 2023 (UTC)


 * Unfortunately the baby has been thrown out with the bath water. The section explained why physicists prefer the kilogram instead of the gram as base unit: the kilogram, in contrast to the gram, is coherent with the electrical units ampere and volt. See link. Ceinturion (talk) 21:50, 18 July 2023 (UTC)
 * The "bathwater" was longer than the entire rest of the article. If you feel that this point is important and you can find reliable sources, then by all means find a way to put it back, perhaps in the "history" section. The material is still in Draft:Kilogram in the Giorgi system. As I said, I feel that is is more relevant to the metric system as a whole than it is to the kilogram. I am just one editor, with no more (or less) authority than you have. -Arch dude (talk) 01:42, 19 July 2023 (UTC)