After 130 years of using standard platinum-iridium weights stored at the International Bureau of Weights and Measures near Paris, scientists have adopted a new definition of physical quantity as the standard definition of a kilogram. From May 20, World Metrology Day, a kilogram will be measured by a physical constant.
Due to the physical processes and the loss of atoms of the reference weight kg kettlebell in Paris for all time of existence has decreased by approximately 50 µg. Therefore, in 2018, the scientific community decided not to use the physical standard in favor of the constant known as the Planck constant. This coefficient relates the quantum of energy of any linear oscillatory physical system with its frequency and is denoted by the letter h.
For accurate reproduction of the kilogram can now be used kibble scales, developed in 1988 by the British physicist Robert Kibble. Their essence is to balance the weight of the load by attracting electromagnets to each other. Direct measurement of the weight is carried out through the Planck constant, where the mass is proportional to the product of current and voltage.
For everyday life, this change will not entail any changes. A lot of things will continue to be measured in kilograms. First of all, the new standard is necessary for scientists who will be able to use more accurate tools in their calculations.