Quark
The quark model was independently proposed by physicists Murray Gell-Mann and George Zweig in 1964. Quarks were introduced as parts of an ordering scheme for hadrons, and there was little evidence for their physical existence until deep inelastic scattering experiments at the Stanford Linear Accelerator Center in 1968. Accelerator experiments have provided evidence for all six flavors. The top quark, first observed at Fermilab in 1995, was the last to be discovered.
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.