Let's be clear: One kilogram of sugar will always weigh one kilogram. But this is a scientific revolution that relates to the pound weight that runs from 13th to 16th November, 16th in Versailles, for the 26th general weight and weight conference.
So far, the kilogram is measured by weight, an international prototype of pounds, also known as the "big K". The cylinder was as large as the egg, platinum and iridium, exceptionally thick alloys, created in 1875.
What is a kilogram?
Kilogram determines the mass (which is usually called the weight) of the Earth's object. It was defined as 1795 as the weight of one liter of pure water at a temperature of 4 ° C.
Now, while all units are defined by the General Weight and Measurement Conference now measured by mathematical formulas (see below), the kilogram remains established with a physical object known as the "large K". But this … moved the weight!
Attention, we are talking about the variation of the micrograph – as much as the flying wing – but at a time when scientists have to weigh endlessly small, the "big K" had its own day.
"Big K", a well kept secret in France
"Big K", which has so far defined a kilogram, is jealously guarded at the International Bureau of Weighing and Measures (BIPM), a mass-guarantee institution located in the Saint Cloud National Park, southwest of Paris.
Indeed, he is stored under a triple glass bell, in a safe. This safe can only be opened with three keys, each of which has three different persons (BIPM Director, President of the International Task Board and Measures and Director of the National Archives of France).
"Big K" only saw it three times in the open, in 1889, 1948 and 1989.
Kilogram is connected to the other and the meter
26. The General Conference of Weights and Measures will therefore move the definition of pounds into a formula that is both mathematical and physical, Planck's constant, introduced by the German physicist Max Planck at the beginning of the 20th century.
At this constant, the kilogram will be tied to the second and the counter. "It will not have a direct impact on everyday life, but this new definition will have applications in the field of physics, industry and health at a time when we are asked to measure particles more and more in the air, water or blood! Thomas Grenon, Director of LNE, National Laboratory for Metrology and Surveying.
What are the international units of measurement?
Seven International Measurement Units have defined the Universal Conference of Weights and Measures: Kilo, Meter, Second, Ampere, Kelvin (Temperature), Mole (Quantity of Material) and Candle (Light intensity).
The General Conference of Weights and Measures, whose first iteration was held in 1889, defines these measures. It brings together 58 member states (from France to Japan, Brazil, Egypt, Germany …) and 41 Associated States.