Thursday , July 29 2021

How much is one kilogram? This definition changes



"Big K" farewell! The General Conference of Weights and Measures (GFCM) has this Friday at the Versailles a new system of international measurement, independent of physical objects.

"In an important decision, representatives from 60 countries voted in favor of redefining the International Unit System (SI), forever changing the world definition of kilograms, ampersand, kelvin and from moles," was announced in a statement by the Bureau of International Weight and Size (BIPM).

Concrete? To date, one kilogram has been defined as being equal to the mass of "Big K", a platinum and cylindrical iridium carefully preserved since 1889 at the International Bureau of Weights and Measures (BIPM) in Sèvres, near Paris. However, scientists realized that the mass of international prototypes had little variation compared to six copies of controls made at the same time.

READ ALSO>Universal size: Big K is no longer heavy

This variation is definitely an anecdote for ordinary people when it comes to making a market. But it can be a problem: science and industry have entered a very small era with the development of quantum technology.

Application in May 2019

The kilogram will now be determined from the Planck constant (h) quantum physics. Other noted changes: Kelvin, measured from water, will be redefined from the Boltzmann constant (k), which is related to the measurement of thermal agitation from the basic constituents of the body.

Ampere will be connected to the base charge (e), the electric charge of the proton. Moles, units of material quantity, used mainly in chemistry will be determined directly by correcting Avogadro's (NA) constant.

The General Conference on Weights and Measures, made at the end of the 19th century, meets every four to six years to discuss and possibly modify the international system standardization unit on a global scale. Changes will be implemented starting May 20, 2019.


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