International Prototype Kilogram shed 100 years last century . atomic measurement is set from the highly - guarded metal detector . German scientists are figuring out how many atoms are in a certain sphere . Method methods allow them to redefine the kilo based on the number of atoms .
International Prototype Kilogram shed 100 micrograms last century . Kilogram measurement is set from the highly-guarded metal cylinder . German scientists are working out how many atoms are in a certain sphere . Method should allow them to redefine the kilo based on the mass of atoms .