At the end of the 19th century, when the science of electricity was still in its infancy, one man made a discovery that forever changed our understanding of the world. This man is Heinrich Hertz, and his experiments with electromagnetic waves ushered in a new era in physics and technology.

Discovery of electromagnetism

In the second decade of the 19th century, Danish physicist and chemist Hans Christian Ørsted conducted research on Volta's electric batteries and the conductivity of electric current. In the spring of 1820, while preparing for one of the lectures on electricity that he was to give at the University of Copenhagen, Oersted made an amazing discovery.

Wanting to demonstrate to his students how a conductor heats up when connected to a voltage source, he noticed that the flow of electric current caused the needle of a nearby compass to deflect. His research in the following months showed that the movement of electric charges was responsible for creating a magnetic field. And not only in conductors through which current flows, but also in permanent magnets.

Effect of current on magnetic field

Further observations showed that the magnetic field depends on the direction of current flow and its intensity. Thanks to this discovery, an electromagnet was later created, which, powered by Volta's battery, was used to construct an electric telegraph or telephone handset.

However, the most important consequence of Oersted's discovery was Michael Faraday's construction of an electric current generator, which resulted in the ability to produce high-power electricity, far superior to Volta's batteries.

Faraday demonstrated that a changing magnetic field could induce an electric current in a conductor, which became the basis for understanding the operation of transformers and alternators. This phenomenon was called electromagnetic induction and formed the basis of modern electrical engineering.

Discovery of electromagnetism

However, returning to Oersted's observations and research, the scientist discovered one of the greatest natural phenomena: electromagnetism. Oersted's achievement, combined with the theory of Faraday, who in 1831 showed that an alternating magnetic field induces an electric current, became the core of a theory developed by another scientist, James Clerk Maxwell.

Maxwell described all electrical and magnetic phenomena and their relationships in the form of a system of mathematical equations. Maxwell's equations showed that electric and magnetic fields propagate in a vacuum at the speed of light in the form of waves.

Maxwell's theory had a huge impact on the development of physics, predicting the existence of electromagnetic waves and opening the way for their practical use.

Heinrich Hertz and radio waves

However, the man who brought radio waves from the realm of mathematical theory to the real world was the eminent German physicist Heinrich Hertz (February 22, 1857 - January 1, 1894).

Heinrich Hertz's life was short, but his contribution to science was invaluable. During his 37 years, he achieved significant heights: his main triumph was the experimental confirmation of the electromagnetic theory of light proposed by James Maxwell.

Hertz not only proved the existence of electromagnetic waves, he opened a new page in the history of physics, which paved the way for numerous discoveries and inventions in the field of wireless communications.

Heinrich Hertz was an exceptionally talented student of the famous German scientist Hermann von Helmholtz.

The master of the future discoverer of radio waves was a doctor by training and made significant contributions to physiology, especially in the field of research related to the release of heat by processes occurring in living organisms, as well as in connection with research on nerve impulses.

However, he gained greatest fame as a physicist. He formulated the fundamental principle of conservation of energy, and also studied mechanics, acoustics, thermodynamics, light, electricity and magnetism.

In 1879, Helmoltz invited Hertz to study Maxwell's theory as part of his doctoral dissertation. However, Hertz refused, considering that the question was too complicated for him, and submitted a doctoral dissertation on electromagnetic induction, which he defended with honors at the University of Berlin in 1880.

In April 1886, Hertz conducted a study of electromagnetic induction. During one of his experiments, while evaluating the performance of induction coils, he noticed a spark flaring up in a Leyden bottle nearby.

There was no electrical connection between the coil and the bottle, so the energy needed to make the spark fly had to be generated by electromagnetic waves. This unexpected discovery prompted Heinrich Hertz to begin systematic research into the phenomenon of electromagnetism.

Hertz's research

In the second half of the 1880s, Hertz conducted many studies to determine the properties of the waves he produced. He sent the results of these studies to Helmholtz, who published them in the proceedings of the Berlin Academy.

The scientist also built a directional source of electromagnetic waves. He surrounded his generator with a parabolic metal mirror. He also built a directional radio wave receiver operating on a similar principle.

These were important instruments because with such a directed beam of radio waves and a directional receiver, he could carry out more complex research. By superimposing the wave sent by the apparatus and the wave reflected from a flat sheet of metal, Hertz created a so-called standing wave and studied its properties.

While studying standing waves, Hertz discovered that they are formed as a result of the interference of two waves - outgoing and reflected. This phenomenon allowed him to measure the wavelength and propagation speed of radio waves. Hertz also showed that radio waves could travel through various materials and be deflected by metal objects, highlighting their wave nature.

These discoveries confirmed Maxwell's predictions and showed that radio waves and light are different forms of the same phenomenon - electromagnetic radiation.

However, he did not realize the potential of his discovery - when asked what open radio waves could be used for, he replied: “I think it’s useless!”

Potential of electromagnetic phenomena

Today we know what potential lies in electromagnetic phenomena. The waves discovered by Hertz were used in communication between people, mainly in communications. Without Hertz's discovery, we would not have radio, television, mobile telephony, Wi-Fi and Bluetooth communications. The greatness of his discoveries is evidenced by the fact that science adopted a unit of frequency named after the scientist, “Hertz.” This is a tribute to the man who revolutionized communication between people.