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The kilogram (also spelled kilogramme [1]) is the base unit of mass in the International System of Units (SI), having the unit symbol kg. [1] The word "kilogram" is formed from the combination of the metric prefix kilo- (meaning one thousand) and gram ; [ 2 ] it is colloquially shortened to " kilo " (plural "kilos").
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 ...
Other units of measure which did not rely on specific artefacts were controlled by other bodies. 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 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]
He did, however, propose a decimal system of weights in which his "[decimal] pound" would have been 9.375 ounces (265.8 g) and the "[decimal] stone" would have been 5.8595 pounds (2.6578 kg). [41] A depiction of a medieval German scale weighing bales of wool according to the local stone.
Scientists want to define the kilogram by gravity—and not just electricity. Here’s why correctly quantifying mass is more important than you think.
The base units are defined in terms of the defining constants. For example, the kilogram is defined by taking the Planck constant h to be 6.626 070 15 × 10 −34 J⋅s, giving the expression in terms of the defining constants [1]: 131 1 kg = (299 792 458) 2 / (6.626 070 15 × 10 −34)(9 192 631 770) h Δν Cs / c 2 .
Americans are celebrating the biggest holiday of the year on Tuesday, Fourth of July, marking the 247th anniversary of the founding of the United States.. The Fourth of July, celebrates the Second ...