planck constant

For over 100 years, Paris has been the home of Le Grand K - a metal block that defines the exact weight of a kilogram.

Irish physicists found a new form of light with a screw-shaped shape and did not follow the law of momentum.

Since the World Science Measurement Day 20/5/2019, the definition of a new kilogram will be officially applied.

The kilogram (kg) has been used as a standard mass measurement since the French revolution, based on the exact mass of a metal block being stored in Paris. However, kilograms may