World News
Kilogram definition set to change─── 09:24 Sun, 18 Nov 2018
Scientists have changed the way the kilogram is defined.
BBC reports that currently, it is defined by the weight of a platinum-based ingot called "Le Grand K" which is locked away in a safe in Paris.
Earlier this week a researchers' meeting in Versailles voted to get rid of it in favour of defining a kilogram in terms of an electric current.
How it works is that electromagnets generate a force. Scrap-yards use them on cranes to lift and move large metal objects, such as old cars. The pull of the electromagnet, the force it exerts, is directly related to the amount of electrical current going through its coils.
There is, therefore, a direct relationship between electricity and weight. So, in principle, scientists can define a kilogram, or any other weight, in terms of the amount of electricity needed to counteract the weight.
Le Grand K has been at the forefront of the international system of measuring weights since 1889.
Several close replicas were made and distributed around the globe. But the master kilogram and its copies were seen to change - ever so slightly - as they deteriorated.
BBC
