The Kilogram is finally being completely redefined

Nations have finally agreed to a new definition of Kilogram.

After about 130 years, the definition of Kilogram unit has finally seen a massive change. The Kilogram which was initially defined using a platinum-iridium cylinder, called “Le Grand K”, placed outside of Paris had incurred some problem over time which needed to be resolved. Now, representatives from as much as 60 new countries have consented to a new definition for Kilogram at a consortium held yesterday at the General Conference on Weights and Measures held in Versailles, France.

Although this type of redefinition won’t necessarily affect the general practices, this still is a long-time awaited redefinition. “The SI redefinition is a landmark moment in scientific measurement,” mentioned Jan-Theodoor Janssen, the Director of research at the UK’s National Physical Laboratory.

According to the new definition of the Kilogram, the unit is now defined completely by natural phenomenon. The Kilogram is now being defined in terms of the Planck’s constant, (h). So, the new value of kg is defined from Plank’s constant whose value is set at 6.626 070 15 × 10–34 kg m2 s–1.

Initially, the Kilogram unit was defined by a set weight placed in a closed environment from which different sample weights were taken. Over time, however, differences started to occur between the different samples and the standard.

Apart from Kilogram, the units for ampere, the kelvin and the mole have also been changed. The ampere is now being defined from the elementary electrical charge, (e), the Kelvin is defined from the Boltzmann constant (k).

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