since monday the definition changes

On May 20, the new definition of kilogram, kelvin, ampere and mole, as agreed in November 2018 at the General Conference of Weights and Measures held in France.

In this way, the kilo will no longer be calculated as it has been for over 120 years, with a weight created in the nineteenth century, but it will be measured in a quantum way, which will provide better precision to scientific research.

This new system of measurements was decided in November at Versailles by the General Conference on Weights and Measures (GFCM), organization created in the late nineteenth century and meets every four or six years.

Representatives from 60 countries then made "a historic decision" in favor of a new definition of International System of Units (SI)which implies modifying the global definition of the kilogram as well as the ampere, kelvin and mol.

In addition to way the mbad is calculatedthe basic unit of temperature (kelvin), the intensity of the electric current (the ampere) and that of the substance (the mole) will also be different.

All these measures will be based on universal constants, which are, by definition, invariable. For a kilo, an ampere or a kelvin as in a laboratory in Spain or in a scientific base installed on Mars, he said ABC.

The The definition of the kilo hitherto depended on the metal cylinder called "Great K", the original of which has been preserved since 1889 at the International Bureau of Weights and Measures (BIPM) in Sèvres, a few kilometers west of Paris.

However, scientists have verified that the mbad of this international prototype it had slightly varied from the other six copies made in the late nineteenth century of the same cylinder composed of platinum and iridium.