654877bd_erials_Science_and_Engineering__Significance
[Date] 1913 [Candidate Moment] Niels Bohr publishes his model of atomic structure. [Significance] 
Introduces the theory that electrons travel in discrete orbits around the atom's nucleus, with the chemical properties of the element being largely determined by the number of electrons in each of the outer orbits.
Greatest Moments in Materials Science and Engineering
Significance