India officially adopted the new definition of the kilogram, aligning with the international standard set by the General Conference on Weights and Measures (CGPM) in 2018.
The kilogram was defined as the mass of a platinum-iridium cylinder called Le Grand K (kept in France).
Over time, microscopic changes in the artifact’s mass led to inconsistencies.
The kilogram is now defined using the Planck constant (hh) and the Kibble balance.
The Planck constant is exactly 6.62607015 × 10⁻³⁴ kg·m²/s, fixing the definition of kg in terms of quantum physics.
A high-precision electromagnetic scale that measures an object’s weight using electric and magnetic forces.
It allows scientists to define mass independently of a physical object, ensuring greater accuracy and stability.
- Greater Accuracy: The new kg is stable and unchanging, unlike a physical object that can degrade.
- Consistency Across Science & Industry: Essential for nanotechnology, pharmaceuticals, and advanced manufacturing.
- Part of a Larger Redefinition: Along with the kilogram, the definitions of ampere, kelvin, and mole were also revised.
No noticeable change for the public—a kilogram of sugar or rice still weighs the same.
However, for scientists and industries that rely on ultra-precise measurements, this change is significant.
This shift marks a historic milestone in measurement science, making the kilogram truly universal and immutable!
