Leonard has been established to have been a child prodigy and a gifted scientist with an impressive knowledge of theoretical physics. His work as an experimental physicist often includes the use of lasers, such as a helium–neon laser or free-electron laser, and his research topics have varied from Bose–Einstein condensates and foundations of quantum mechanics to soft cosmic rays at sea level and development of novel rocket propellants. Leonard designs experiments in order to test theories but, according to Sheldon, his work is mostly derivative and thus unimportant.