This Dutch farmer’s son is undoubtedly one of the great theoretical physicists of history not only for his numerous scientific contributions but also for his dedication and effort in pursuit of the progress of physics and its teaching. In this last field, the fact that he was responsible for the physicians for a long time received an appropriate training in physics,, and that even after being retired at the age of seventy of from his post at Leyden University, he continued to teach until a few weeks before his death.

Lorentz was the first to use the term electron, although initially to designate elementary particles, introducing the atomistic theories in Maxwell’s theory and creating models Which would explain the interaction between radiation and matter, convinced that the latter had an atomic structure. As a result of these works, he framed Maxwell’s theory in a microscopic theory of electromagnetism considering the existing fields within matter in the void spaces between particles. All this led to what would be one of the greatest successes of his career as a theoretical physicist, the exact prediction of the normal Zeeman effect by which he received the Nobel Prize in Physics in 1902 along with Pieter Zeeman, ie by the effect of a field Magnetic uniform over spectral lines. It is curious that the normal Zeeman effect described by Lorentz is the less usual, having to frame his study within the quantum theories of radiation and that by coincidence coincides in its results with those obtained classically by Lorentz.

Undoubtedly the name of Lorentz is familiar to us above all by the Lorentz-Einstein transformation of application in special relativity when changing reference system. To explain the negative result of the Michelson-Morley experiment Lorentz adhered to Fitzgerald’s hypothesis that every moving body in the ether would undergo a longitudinal contraction. Lorentz introduced the idea of local time as mathematical artifice to work with this contraction resulting from the internal tensions produced by the movement of the body in the ether. This local time as mathematical artifice would be endowed by Einstein shortly after a clear physical sense by abandoning the concept of Newtonian absolute time. Lorentz was always a classic physicist maintaining his reserves towards the ideas of Einstein but doing a fundamental work in the development of the same ones. The classical idea of physics was more clearly seen with the advent of quantum theory, resisting admitting the death of determinism and the introduction of new concepts such as the quantization of energy or the fact that the position and momentum of a Particles became blurred concepts. Lorentz died in 1927, the year in which Schrödinger showed the world his equation and the concept of wave function burst in with all its force.