Strange quark
The first strange particle (a particle containing a strange quark) was discovered in 1947 (kaons), but the existence of the strange quark itself (and that of the up and down quarks) was only postulated in 1964 by Murray Gell-Mann and George Zweig to explain the Eightfold Way classification scheme of hadrons. The first evidence for the existence of quarks came in 1968, in deep inelastic scattering experiments at the Stanford Linear Accelerator Center. These experiments confirmed the existence of up and down quarks, and by extension, strange quarks, as they were required to explain the Eightfold Way.
Lawrence H. Knox
Lawrence Howland Knox (September 30, 1906 – 1966) was among the first African Americans to receive a PhD in chemistry, following his brother William Jacob Knox (1904–1995). He worked with Paul Doughty Bartlett on an experiment for testing organic mechanisms in chemistry which involved the use of the molecule bicyclo(2.2.1)heptane, a type of bicyclic molecule. Knox was the grandson of a slave.