To clarify slightly, the proposal wasn't to switch from defining the kilogram as the mass of one particular lump of platinum to one particular lump of silicon.

To clarify slightly, the proposal wasn't to switch from defining the kilogram as the mass of one particular lump of platinum to one particular lump of silicon. Instead, the idea was to define the kilogram as the mass of a certain number of Silicon 28 atoms and use the silicon sphere to get that number as close as possible to our old kilogram. This would then allow independent scientists to make their own spheres, calculate the number of silicon atoms in the sphere, and have their own reference benchmarks for the kilo without needing to check in with Paris.