Kilogram: Difference between revisions

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<onlyinclude>A '''kilogram''' is the [[SI]] [[units|unit]] of [[mass]] and one of the 7 base units. It is the only SI unit with a [[prefixes|prefix]].</onlyinclude> Originally the gram was going to be the base unit, but due to a historical quirk regarding an artifact used to define the kilogram,<ref>Bureau International des Poids et Mesures, ''"kilogram": a historical quirk'' [Online], Available: http://www.bipm.org/en/measurement-units/history-si/name-kg.html</ref> the kilogram was chosen as the SI base unit for mass. The kilogram is currently the only base unit to rely on a physical artifact for its definition, which is more problematic than it sounds. For a fascinating essay on the metrology outlook on this problem please see [http://www.nist.gov/pml/si-redef/kg_redefinition.cfm NIST's website].
[[Category:Translated to Spanish]]
[[es:Kilogramo]]
<onlyinclude>A '''kilogram''' is the [[SI]] [[units|unit]] of [[mass]] and one of the 7 base units in the International System of Units (SI). It is the only SI unit with a [[prefixes|prefix]].</onlyinclude> The prefix "Kilo" is used for both the name and symbol of kilogram and is equal to 1000 or 10<sup>3</sup> [[gram]]s. Originally the gram was going to be the base unit, but due to historical reasons regarding an artifact used to define the kilogram, the kilogram was chosen as the SI base unit for mass. As of 2018, the kilogram (kg) is now defined by taking the fixed numerical value of [[Planck's constant]] ''h'' to be 6.62607015 × 10<sup>−34</sup> kg m<sup>2</sup> s<sup>−1</sup>. This decision was made in order to ensure the long-term stability of the unit of [[mass]].<ref>Bureau International des Poids et Mesures, "''Mise en pratique'' for the definition of the kilogram (2020)," [Online], Available: https://www.bipm.org/en/search?p_p_id=search_portlet&p_p_lifecycle=2&p_p_state=normal&p_p_mode=view&p_p_resource_id=%2Fdownload%2Fpublication&p_p_cacheability=cacheLevelPage&_search_portlet_dlFileId=41489972&p_p_lifecycle=1&_search_portlet_javax.portlet.action=search&_search_portlet_formDate=1622783457642&_search_portlet_query=kilogram&_search_portlet_source=BIPM</ref>
<ref>Bureau International des Poids et Mesures, "Appendix 4. Historical notes on the development of the International System of Units and its base units," [Online], Available: https://www.bipm.org/en/publications/si-brochure.</ref>


For a fascinating video on the origin of the kilogram and the impact of the new definition of a kilogram see Veritasium's video below.
==Conversions==
==Conversions==
<html><br /> <iframe src="http://energyeducation.ca/simulations/converter/converter.php?defaultMeasure=Mass&defaultFrom=kilogram&defaultTo=pound" scrolling="no" width="750" height="200"> </iframe><br /> </html>
<html><br /> <iframe src="https://energyeducation.ca/simulations/converter/converter.php?defaultMeasure=Mass&defaultFrom=kilogram&defaultTo=pound" scrolling="no" width="750" height="200"> </iframe><br /> </html>


==Video: The kg is dead, long live the kg==
<html>
<iframe width="800" height="500" src="https://www.youtube.com/embed/c_e1wITe_ig" title="YouTube video player" frameborder="0" allow="accelerometer; autoplay; clipboard-write; encrypted-media; gyroscope; picture-in-picture" allowfullscreen></iframe>
</html>
==Further Reading==
*[[Mass]]
*[[Weight]]
*[[Planck's constant]]
*[[Mass-energy equivalence]]
*Or explore a [[Special:Random|random page]]
==References==
==References==
{{reflist}}
{{reflist}}
[[Category:Uploaded]]
[[Category:Uploaded]]

Latest revision as of 20:21, 20 December 2021

A kilogram is the SI unit of mass and one of the 7 base units in the International System of Units (SI). It is the only SI unit with a prefix. The prefix "Kilo" is used for both the name and symbol of kilogram and is equal to 1000 or 103 grams. Originally the gram was going to be the base unit, but due to historical reasons regarding an artifact used to define the kilogram, the kilogram was chosen as the SI base unit for mass. As of 2018, the kilogram (kg) is now defined by taking the fixed numerical value of Planck's constant h to be 6.62607015 × 10−34 kg m2 s−1. This decision was made in order to ensure the long-term stability of the unit of mass.[1] [2]

For a fascinating video on the origin of the kilogram and the impact of the new definition of a kilogram see Veritasium's video below.

Conversions



Video: The kg is dead, long live the kg

Further Reading

References

  1. Bureau International des Poids et Mesures, "Mise en pratique for the definition of the kilogram (2020)," [Online], Available: https://www.bipm.org/en/search?p_p_id=search_portlet&p_p_lifecycle=2&p_p_state=normal&p_p_mode=view&p_p_resource_id=%2Fdownload%2Fpublication&p_p_cacheability=cacheLevelPage&_search_portlet_dlFileId=41489972&p_p_lifecycle=1&_search_portlet_javax.portlet.action=search&_search_portlet_formDate=1622783457642&_search_portlet_query=kilogram&_search_portlet_source=BIPM
  2. Bureau International des Poids et Mesures, "Appendix 4. Historical notes on the development of the International System of Units and its base units," [Online], Available: https://www.bipm.org/en/publications/si-brochure.