The four base units of the Metric system will be redefined

The next General Conference on Weights and Measures is coming, at which an important event was announced. There was an urgent need to change the definitions of the kilogram, kelvin, ampere and mole - the four basic elements of the Metric system. This is due to the desire of most states to use new instruments and measurement technologies that are incompatible with old standards.

So, the well-known kilogram will no longer be tied to the mass of a standard cylinder made of platinum and iridium, which is stored under glass armor in France and is retrieved to calibrate other instruments only once every 40 years. In the 21st century, the mass of objects is no longer measured on scales, but indirectly - using Planck's constant. To do this, an extremely expensive but very accurate device known as the "Kibble balance" was specially designed.

Kibble Balance, formerly called watt balance, is a measuring device that measures the amount of electrical current required to generate sufficient electromagnetic force to balance a given mass. And then, with the help of Planck's constant, they pass from electricity to the mass of the object, and get the coveted kilogram. Because it is easier and more reliable to measure the parameters of electric fields than to directly compare the masses of individual objects.

As the metrologists themselves note, for consumers, in fact, nothing will change, a kilogram will remain a kilogram, but scientists in numerous laboratories around the world will breathe a sigh of relief. Likewise, under the new standards, the mole, ampere, and kelvin are being reclassified, as before, during the last general conference, they changed the definition of meter, second and candela. The very procedure for redefining units of measurement will be broadcast online.