World of Waves

By Simone Malacrida

This book is a journey into the world of electromagnetic waves and focuses on a historical and technological account of how they have routinely entered the daily life of society today. All sources of electromagnetic waves, natural or man-made, are carefully analyzed through language suitable for everyone and with repeated examples.

• Language: English
• Publisher: Simone Malacrida
• Release date: Dec 14, 2022
• ISBN: 9798215648803

Simone Malacrida

Simone Malacrida (1977) Ha lavorato nel settore della ricerca (ottica e nanotecnologie) e, in seguito, in quello industriale-impiantistico, in particolare nel Power, nell'Oil&Gas e nelle infrastrutture. E' interessato a problematiche finanziarie ed energetiche. Ha pubblicato un primo ciclo di 21 libri principali (10 divulgativi e didattici e 11 romanzi) + 91 manuali didattici derivati. Un secondo ciclo, sempre di 21 libri, è in corso di elaborazione e sviluppo.

Book preview

ELECTROMAGNETIC WAVES: HISTORY AND PROPERTIES

In this first chapter we will delve into the broad space represented by the phenomena and inventions that led to man's discovery of electromagnetic waves and related properties. This exploration will be carried out using three different types of routes. A first itinerary will take us through the meanders of human history, making us perceive how scientific discoveries and the lives of inventors over the centuries are intimately linked to the course of historical events and how places and times have a basic importance in science as well. A second journey will provide an understanding of the main properties of electromagnetic waves, comparing this physical phenomenon with other natural events that can be described as waves. Finally, a virtual exploration of the electromagnetic spectrum will provide insight into the full breadth of the nature of these particular waves.

––––––––Electricity and magnetism: history of two parallel paths––––––––

Electrical and magnetic phenomena were unknown to primitive man and the first human civilizations that populated Mesopotamia, Egypt and Persia. The earliest studies of such phenomena date back to ancient Greece by the philosopher Thales around the sixth century BC.

From the properties discovered by Thales of certain fossil resins, such as amber, that became electrified by rubbing derived the name electricity that we all use, in ancient Greek in fact amber was called electron. Some speculate that the classical behavior of magnetite in attracting iron filings was known even earlier in China, where the first rudimentary compass would also have been built, but this supposition is not supported by archaeological and historical discoveries. In 1936, Babylonian earthenware jars dating from about three hundred years before Christ were recovered near Baghdad that contained perhaps the first stacks used to make layers of metal deposited on various objects. Centuries later, in ancient Rome of the first century AD, both Pliny the Elder and Seneca described the properties of amber and investigated the types of lightning.

These ancient studies were followed by more than a millennium of silence on such phenomena except for the English monk Venerable Bede who described, around the eighth century, amber-like properties in other materials and Peter Peregrine's study in which the terminology of North Pole and South Pole was first introduced and in which the attractive and repulsive properties of magnets were studied.

The first scientific studies of electrical and magnetic phenomena began much later, after the scientific and cultural revolution of the Renaissance and Copernicus and after the definition and subsequent establishment of the modern scientific method introduced by Galileo Galilei. Incidentally, the same scientists who tried their hand at the feat of describing such phenomena, including Galilei and Newton, made gross errors by attributing the electrical and magnetic properties of certain materials to strange effluvia or air movement. In those centuries, other disciplines such as mechanics, hydraulics and astronomy were developed more, the latter thanks mainly to the invention of the telescope, which made it possible to visualize celestial objects much better than observation with the naked eye. In particular, optics with all its associated phenomena was greatly developed and studied in the seventeenth century. Many properties of optics, and of light in particular, would come in very handy two hundred years later, in the middle of the nineteenth century, the great century of electricity and magnetism, and that is why we mention them at the beginning.

A considerable amount of electrical and magnetic phenomena were discovered in the eighteenth century, although these inventions almost always remained disconnected from each other and without an apparent logical thread uniting them. Interest in such phenomena also spread as curiosity and as a game in the salons of the eighteenth-century European aristocracy and upper middle class, and many somewhat equivocal characters offered miraculous methods of cure based on these paranormal phenomena.

It began to be understood that both electricity and magnetism could be repulsive or attractive in the sense that, by changing certain conditions, a force could be seen to move electrified objects away or closer together. This created further misunderstandings, as most scientists began to think that there were two electrical fluids, one glassy meaning positively charged and one resinous meaning negatively charged. The names glassy and resinous referred to the different behavior that glass and resins, including amber, had when electrified by rubbing. In the mid-eighteenth century, American Benjamin Franklin, based on some correct observations of electrical phenomena, devised the first lightning rod, and the first installations went into operation only six years after the first successful experiment. Toward the end of the century, the French scientist Charles de Coulomb, built a special balance in which he was able to measure the force of electrical phenomena and mathematically described this phenomenon by means of the law that still bears his name and is the basis for the study of electricity.

However, it was two Italian scientists, Luigi Galvani and Alessandro Volta, who gave a definitive scientific breakthrough to the study of electricity and opened up whole new fields of application. Galvani observed muscle contractions in the legs of a frog in contact with a metal conductor and hypothesized the presence of animal electricity. Although he was in the wrong, Galvani's studies gave great impetus to the physiology and biological applications of electrical manifestations.

Galvani's observations on the behavior of the frog subjected to the action of electricity prompted Volta to experiment and build the first real battery in human history.

Volta always had a passion for the study of electricity and all that strange world, as learning these disciplines could appear at that time. He studied the chemistry of gases and their combustion by electric sparks and was the first to discover the existence of methane. When Galvani published his studies, Volta understood that electricity did not depend on the animal (the frog in question) but on the metal conductor, particularly the pair of metal conductors used. To demonstrate this, he conducted experiments with zinc and silver, which he had identified as the most effective pair of dissimilar metals, constructing two different pieces of these metals introduced into