Chiliogramma

[thumb|upright=1.35|[Systema internationale unitatum post definitionem anno 2019 effectam: chiliogramma nunc secundo, celeritate lucis, et constanti Planckiana fingitur; praeterea, *ampere* chiliogrammate non iam nititur.]]
[thumb|Imago exemplaris [Lutetiae conservati. Non est photogramma sed imago computatro facta, quod nemo chiliogramma publicum videre nec tangere potest.]]
thumb|upright=0.8|Chiliogramma antiquum.

  (-atis, *n.* *vel* -ae, *f.*) Haec definitio verbis simplex sed usu difficilis erat. Secundum autem recentissimas huius unitatis definitiones, haec cognatio est vera usque ad triginta partes per millionem. Anno 1799, "chiliogramma archivorum" (ut dicitur), ex platino funditum, norma massae factum est. Anno 1889, cylindrus temperationis platini et iridii, prototypus internationalis chiliogrammatis, norma unitatis massae in omne systemate metrico factum est, et sic mansit usque ad annum 2019. Chiliogramma erat ultima ex unitatum systematis internationalis quae per rem corporeum definiebatur.

### Historia hodierna 
Ab anno 1889 1 chg erat, per definitionem, massa quae continetur in exemplari prisco apud Officinam Internationale in Pondera et Mensuras Lutetiae sito. Exemplar metallis platino (90%) atque iridio (10%) factum est. In forma cylindri 39 mm alti, cum radio 19.5 mm fusum est.

Definitio *chiliogrammatis* rite die 20 Maii 2019 . Nova definitio non iam de prisco exemplari, sed de constanti Planckiana (), de celeritate lucis () et de definitione secundi— cyclis radiationis electronum quae inter status fundamentalis atomi Cs 133 moventur ({\Delta\nu})—dependet:

1\,\text{kg} = \frac{h}{6{,}626\,070\,15 \cdot 10^{-34}}\,\frac{\text{s}}{\text{m}^2} = \frac{299792458^2}{9192631770 \cdot 6{,}62607015} \cdot 10^{34}\,\frac{h \cdot \Delta\nu}{c^2}

*Gramma
*Gravimetria
*Inertia
*Litrum
*Massa
*Massa contra pondus
*Newtonium
*Maximilianus Planck
*Pondus
*Systema metricum
*Tonna

## Notae
## Bibliographia
* Davis, Richard. 2003. "The SI unit of mass." *Metrologia* 40, no. 6 (fasciculus praecipuus: "Mass"): 299–305. .
*Resnick, Brian. 2019. "The new kilogram just debuted. It's a massive achievement." Vox.com, 20 Maii 2019. Editio interretialis.
* Robens, Erich. 2014. "The International Prototype Kilogram." In *Balances, Instruments, Manufacturers, History,* 62–64. Heidelbergae: Springer. ISBN 978-3-642-36447-1. .

## Nexus externi
* National Institute of Standards and Technology: "NIST Improves Accuracy of ‘Watt Balance’ Method for Defining the Kilogram." www.nist.gov.
* National Physical Laboratory: ["Are any problems caused by having the kilogram defined in terms of a physical artefact?"](http://www.npl.co.uk/reference/faqs/are-any-problems-caused-by-having-the-kilogram-defined-in-terms-of-a-physical-artefact-(faq-mass-and-density)) FAQ - Mass & Density, www.npl.co.uk.
* NPL: "Avogadro Project." www.npl.co.uk.
*NPL: "NPL watt balance." www.npl.co.uk.
* Metrologia in Francia: "Watt balance." www.french-metrology.com.
* Australian National Measurement Institute. "Redefining the kilogram through the Avogadro constant." www.measurement.gov.au.
* International Bureau of Weights and Measures: Situs interretialis ministerii proprius. www.bipm.org.
* NZZ Folio: ''"What a kilogram really weighs."'
* NPL. ["What are the differences between mass, weight, force and load?"](http://www.npl.co.uk/reference/faqs/what-are-the-differences-between-mass,-weight,-force-and-load-(faq-mass-and-density)) www.npl.co.uk.
* BBC. "Getting the measure of a kilogram." news.bbc.co.uk.
* NPR. "This Kilogram Has A Weight-Loss Problem." conloquium cum Ricardo Steiner, physico in National Institute of Standards and Technology, www.npr.org.
*"Avogadro and molar Planck constants for the redefinition of the kilogram." www.inrim.it.
*"Realization of the awaited definition of the kilogram." www.inrim.it.

Categoria:Physica
Categoria:Unitates physicae