Letters: October 2017
Your opinions on redefining the kilogram, timing viscosity and Victorian anaesthetics
I am disappointed that metrologists are continuing to define the units of basic physical quantities by fixing the values of fundamental constants (Chemistry World, September 2017, p11). They defined the metre by fixing the speed of light in a vacuum, and now want to define the kilogram by fixing the value the Planck constant.
We do not know that the so-called ‘fundamental constants’ are universally constant. Indeed, some cosmologists have conjectured that the speed of light in a vacuum varies. Why not define the kilogram as the mass of a specified number of silicon-28 atoms?