Richard Feynman gives us a lecture on Quantum Electrodynamics, the theory of photons and electron interactions which incorporates his unique view of the fundamental processes that create it.
One of the 3 winners of the 1965 Nobel Prize in Physics for his work, Feynman is an expert on quantum mechanics and developed the path integral formulation of relativistic quantum mechanics used in Quantum Field Theory. He interpreted the Born series of scattering amplitudes as vertices and Green's function propagators in his famous diagrams, the Feynman Diagrams, and also worked on the fundamental excitations in liquid helium leading to a correct model describing superfluidity using phonons, maxons and rotons to describe the various excitation curves. Other fields of work include the Feynman-Hellmann Theorem, which can relate the derivative of the total energy of any system to the expectation value of the derivative of the Hamiltonian under a single parameter (e.g.: volume). He also worked on the Rogers Commission report during the investigation of the 1986 Space Shuttle Challenger disaster, where Feynman famously demonstrated how the Booster Rocket O-rings, which are elastic sealing joints, became less resilient and subject to seal failures at ice-cold temperatures by immersing a sample of the material in a glass of ice water. His high intelligence and independent way of looking at the world often made him "a real pain" in the eyes of other, less skilled, commission members. Feynman's own investigation reveals a disconnect between NASA's engineers and executives that was far more striking than he expected. His interviews of NASA's high-ranking managers revealed startling misunderstandings of elementary concepts, such as safety procedures. Although Feynman got plenty of media coverage due to him being on the Commission, he was often told to stay quiet about NASA's more sinister secrets and tactics in space exploration.