Talk:International Prototype of the Kilogram

Provenance
This article is the result of a copy-paste move of a subsection of the Kilogram article. The edit history for specific contents can be found in that article's edit history. -Arch dude (talk) 19:01, 23 May 2019 (UTC)

Retired
So what happens to them now that they're obsolete? Are they still kept around for some practical reason? — Omegatron (talk) 00:52, 5 May 2020 (UTC)


 * If nothing else, they are important historical artifacts that should be preserved in a museum if they cease to have any practical use.
 * One obvious reason for keeping them for now is to see how much they drift in mass relative to the new standard, as this would make possible an estimated of how much they drifted, and in what direction, when they were the standard. Running an experiment with them in the future would allow an answer to several questions that this very Wikipedia article says are unanswerable, such as whether the IPK is drifting and the replicas are not, or vice versa. 47.139.40.129 (talk) 02:19, 15 February 2024 (UTC)

New consensus value of the IPK
A while ago (as in, several months ago), the folks at the BIPM carried out a series of comparisons between the prototype kilograms using several different methods, such as Kibble balances, the XRCD method, and vacuum mass comparators (you can find the link to the comparisons here), and established the consensus value of the kilogram as 1 kg - 2 μg (standard uncertainty = 20 μg) with respect to the IPK (aka: the IPK is now, definitely, no longer 1 kg) for dissemination purposes (you can find the report itself here, the announcement here, and some background context here). If you read the article that gives the background context, it'll explain the significance of this, but long story short: we are now one step closer to a world where we no longer need to use a cylinder made of platinum-iridium as a primary mass standard - pretty important if you ask me.

The problem, however, is that given the layout of the current page, I don't really know where I can add this in. Thoughts and help? — MeasureWell (talk) 08:23, 16 September 2021 (UTC)