The scientists agreed on Friday to redefine the value of the kilogram, in a resolution they described as historical, and suggested that the accuracy of scientific standards be increased.
Since 1889, the kilogram has been defined as a shiny platinum-erydium block in a special glass container known as the international basic model of kilograms. This block is held at the headquarters of the International Bureau of weights and measures located on the outskirts of the French capital Paris.
Following a week-long meeting at the nearby Versailles Palace, the 60-nation International Bureau of Weights and Measures agreed to redefine the kilogram on a small but unchanged basis called the Planck constant.
Voting was done to update the definitions of amps (unit of measurement of voltage), calvin (one of thermodynamic units) and mole (unit of measurement of material quantity).
All modern mass measures are derived from kilograms, whether micrograms of drugs, gold dust, kilograms of fruit, fish or tons of steel.
The problem is that the weight of the model changes permanently. Even inside its three glass tractors, the model captures accurate particles of dust and is influenced by the atmosphere. Sometimes it needs to be cleaned which can affect its mass.
These changes can have a significant effect. If the model loses part of its mass, the weight of the atoms will theoretically increase while the kilogram should always be weighed.
Scientists have been seeking for decades to determine a fixed value per kilogram derived from stationary physics, according to the way they have behaved to other measurement units supervised by the International Bureau of Weights and Measures.
Experts believe that redefining the kilogram represents the most important redefinition of a unit of measurement since the second was recalculated in 1967, a decision that helped facilitate communication around the world through technologies such as GPS and the Internet.
The new tariffs approved by the International Bureau of Weights and Measures will begin on May 20, 2019.
