The history of electricity - Then and Now

The science of electricity has gradually formed from simple observations of natural phenomena. Compass is the first application.

      The possibility of producing electricity at will was acquired only in the seventeenth century (static machines of Guericke and Huygens), in the early eighteenth century, the discovery of electricity helped to classify the different "fluid" into two categories: the vitreous electricity (positive), the resinous electricity (negative).

      In the eighteenth century, the experiment is sufficiently developed so that we can construct the first theories and experiments and measurements more precise, spend qualitative to the quantitative (Cavendish and Coulomb).

      But static electricity that is produced, and that is the subject of research, can not get much progress. In 1800, the discovery of the stack (Volta) provides electric currents (dynamic power). So is the junction of two categories, electricity and magnetism into electromagnetism. Stringent laws are established (Ampere and Ohm, same year, 1827) and one discovers the induction currents (Foucault, 1850).

      Parallel to this research, a long series of observations and experiments on the conductivity of electricity in gases led to the identification of the phenomena of radiation. Thus the rays are discovered successively positive (Goldstein), the cathode rays (Hertz, J. Perrin, JJ Thomson, P. Lenard) and X-rays (Roentgen), the latter paving the way for remarkable applications in both medicine knowledge of the constitution of matter.

      Maxwell's equations allow the discovery of radio waves (Hertz), the source of radio engineering. So was born the theory of Lorentz (1892-1895) where, at the microscopic level, is associated with moving charges an electric field and magnetic field.

      The work of Pierre Curie on symmetry of physical phenomena, by introducing the concept of prediction, mark a turning point; his studies on magnetism are continued and expanded by his student Paul Langevin. That's when that knowledge of the constitution of the atom states (N. Bohr) and Max Planck's quantum theory sets. Einstein to explain the photoelectric effect, amounts to a granular conception of electricity in 1925, Louis de Broglie operates a synthesis between the wave and particle theories.