The way scientific units are calculated is changing

From Engadget - October 19, 2017

Ever pondered the precision of the international system of units (SI)? (Why should you? You are not going to be called on to measure the temperature in the Large Hadron Collider any time soon). You may be in need of a refresher, then. The kilogram is defined as the lump of platinum-iridium locked in a vault in Paris. The artefact is known to fluctuate in weight (due to surface contamination), making it tricky to define its exact mass.

But, it made the cut for its inclusion in the broader redefinition of units with the acceptance of the so-called watt balance method in 2015. This approach essentially compares mechanical power with electromagnetic power using two methods -- which measure speed as well as experimental values relating the voltage and current in Planck's constant.


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