What is Francis William Aston known for?
I am best known for inventing the mass spectrograph, an apparatus that allows us to determine the masses of atoms with remarkable accuracy. Using this instrument, I discovered a large number of isotopes—atoms of the same element that differ in mass. This work earned me the Nobel Prize in Chemistry in 1922. The mass spectrograph revealed that nearly all elements are mixtures of isotopes, and it provided the empirical foundation for the whole-number rule: the atomic weights of isotopes are very nearly whole numbers. My book *Isotopes* (1922) and later *Mass Spectra and Isotopes* (1933) summarize these findings, which revolutionized atomic theory and our understanding of atomic weights.
Ask Francis William Aston the follow-up →