Audioguía Hall: Electricity and Magnetism

His section deals with the equipment related to static electricity, electrodynamics, magnetism, and electromagnetism.

Electrostatics is the branch of electricity that studies the phenomena related to stationary electric charges and their interactions.

Beginning in the 17th century, scholars started being interested in static electricity, but it was only at the beginning of the e18th century that the first electrostatic generators, in which a rapidly rotating glass globe was electrified by rubbing, appeared.

These electrostatic machines were then built with rotating glass disks or cylinders and, after various adjustments, they were still used until the beginning of the 20th century.

In the second half of the 18th-century electrostatic phenomena increased the interest of the educated society and they represented the opportunity to organize meetings with experimental demonstrations that combined entertainment with science.

Several theories tried to explain a large number of electrical phenomena: for example, Benjamin Franklin, the famous inventor of the lightning rod, postulated the existence of positive and negative charges.

Starting from the end of the 18th century, electrostatics ceased to be an essentially qualitative science and was given a mathematical structure; however, the electrostatic experiments continued to be very popular and the manufacturers presented many didactic tools in order to reproduce them.

In 1800 Alessandro Volta invented the electric battery, the first tool capable of supplying direct current, and in 1820 Hans Christian Ørsted showed for the first time the close connection between electricity and magnetism, after observing that a wire run by current makes a magnetic needle change direction.

André Marie Ampère and Michael Faraday also contributed with significant experimental and theoretical advances to the knowledge of electromagnetic phenomena.

These advances led to the realization, for example, of induction coils and high voltage transformers, that were very common in the laboratories and that slowly replaced electrostatic machines.

The first rudimentary engines and electric generators were also built, even if at first they were not really used.

With the development of electromagnetism, the physics cabinets were enriched with a myriad of demonstration and measurement instruments.

In the 1960s James Clerk Maxwell, extending Faraday's research and studies, made a brilliant theoretical synthesis of electromagnetic phenomena in which light was also included.

Maxwell postulated the existence of electromagnetic waves, which would be experimentally observed by Heinrich Hertz only in the 1880s.

The phenomena related to alternating currents and high-frequency electric oscillations demonstrated by Nikola Tesla and others were also studied.

These studies would be the basis for the first experiments on wireless telegraphy, a technology perfected by Guglielmo Marconi.

In the last decades of the nineteenth century, a better understanding of electromagnetic phenomena allowed the development of more effective dynamos, direct current motors, and the introduction of alternating current machines.

Around 1870 electricity and its applications began to be used on an industrial scale.