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  2. Kilogram - Wikipedia

    en.wikipedia.org/wiki/Kilogram

    The kilogram, symbol kg, is the SI unit of mass. It is defined by taking the fixed numerical value of the Planck constant h to be 6.626 070 15 × 10 −34 when expressed in the unit J⋅s, which is equal to kg⋅m 2 ⋅s −1 , where the metre and the second are defined in terms of c and Δ ν Cs .

  3. International Prototype of the Kilogram - Wikipedia

    en.wikipedia.org/wiki/International_prototype_of...

    The International Prototype of the Kilogram (referred to by metrologists as the IPK or Le Grand K; sometimes called the ur-kilogram, [1] [2] or urkilogram, [3] particularly by German-language authors writing in English [3] [4]:30 [5]: 64 ) is an object whose mass was used to define the kilogram from 1889, when it replaced the Kilogramme des ...

  4. History of the metric system - Wikipedia

    en.wikipedia.org/wiki/History_of_the_metric_system

    Although the definition of the kilogram remained unchanged throughout the 20th century, the 3rd CGPM in 1901 clarified that the kilogram was a unit of mass, not of weight. The original batch of 40 prototypes (adopted in 1889) were supplemented from time to time with further prototypes for use by new signatories to the Metre Convention. [66]

  5. Scientists Want to Define the Kilogram by Gravity—Not ... - AOL

    www.aol.com/scientists-want-define-kilogram...

    In 2018, scientists redefined the kilogram related to the basic electromagnetic principles. But a new study suggests that something similar could be done with gravitational principles as well.

  6. International System of Units - Wikipedia

    en.wikipedia.org/wiki/International_System_of_Units

    After the metre was redefined in 1960, the International Prototype of the Kilogram (IPK) was the only physical artefact upon which base units (directly the kilogram and indirectly the ampere, mole and candela) depended for their definition, making these units subject to periodic comparisons of national standard kilograms with the IPK. [38]

  7. Grave (unit) - Wikipedia

    en.wikipedia.org/wiki/Grave_(unit)

    The modern kilogram has its origins in the Age of Enlightenment and the French Revolution.In 1790 an influential proposal by Talleyrand called for a new system of units, including a unit of length derived from an invariable length in nature, and a unit of mass (then called weight) equal to the mass of a unit volume of water. [4]

  8. Metric system - Wikipedia

    en.wikipedia.org/wiki/Metric_system

    It was invented in France for industrial use and from 1933 to 1955 was used both in France and in the Soviet Union. [ 39 ] [ 40 ] Gravitational metric systems use the kilogram-force (kilopond) as a base unit of force, with mass measured in a unit known as the hyl , Technische Masseneinheit (TME), mug or metric slug . [ 41 ]

  9. Opinion - Once kids start dying, we’ll see how people really ...

    www.aol.com/news/opinion-once-kids-start-dying...

    Before the measles vaccine was invented in 1963, millions of people died every year from this horrific illness. More than 500 children per year in the U.S. were its victims, and that doesn’t ...