From Michael Fenton
Having read your very interesting article on the problems of creating a standard kilogram, I was left with a sense of “What’s the problem?” (22 February, p 32).
If we go back to the definition of a mole we are told that it is the amount of a substance that contains as many elementary entities (molecules) as there are atoms in 0.012 kilograms of carbon-12.
If we know the number of atoms in 0.012 kilograms of carbon-12 is it not simply a case of multiplication to get the number of atoms in 1 kilogram of carbon-12?
West Bromwich, West Midlands, UK
