Rudolf Heinrich Hertz
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This German physicist joined the world of Hamburg on 22 February 1857. As a young man he began to study engineering, but he abandoned his studies and began studying physics. Hermann von Helmotz was a professor and above all a friend throughout his life.
He completed his doctorate in physics at the University of Berlin in 1880, obtaining the qualification of “magna cum laude”. From 1885 to 1889 he was professor of physics at the Polytechnic School of Karlsruhe and from 1889 professor of the University of Bone, in the position assigned by Clausius.
While working at Kiel University in 1883, he dealt with the equation that Maxwell recently achieved for the electromagnetic field. The Berlin Academy of Sciences announced an award for its work in the magnetic field and Helmotz proposed that his student work in this field. Hertz began his work in 1888 without much encouragement, but in 1888 he encountered something unforeseen. Two metal spheres separated by air had prepared an oscillating electrical circuit.
When the potential difference exceeded one level in one direction or another, the spark came from one sphere to another. In these trials he discovered that when in the negative pole there was ultraviolet light the spark jumped more easily. These were the beginnings of the photoelectric effect, which later Einstein served to study the phenomenon and win the Nobel prize.
Maxwell's equation said that electro-magnetic radiation could be produced in the oscillating spark. Each oscillation had to produce a wave, with a radiation of great wavelength. As the light spreads at a speed of 300,000 km/h, the oscillation of the thousandth second would have an approximate wavelength of 300 kilometers.
To detect this radiation Hertz used a rolled wire, leaving a small air space between the spires. When the current generated radiation in the first spire, it would cause current in the second. Hertz saw small sparks jumping on his detector. Placing the detector at different points in the room, it analyzed the characteristics of the waves according to the intensity of the spark and calculated its wavelength. They were 66 centimeters, that is, a million times longer wave than that of visible light. He also showed that these waves were electro-magnetic.
In England Lodge he checked Hertz's essays and in Italy he demonstrated Righi's relationship with light waves. Later, when Marconi used hertzian waves in wireless telegraphy, they were called radiowaves.
Hertz studied cathodic rays at Bon University. These rays seemed to him not corpuscles and waves, as they crossed very fine metal plates. Thomson later found that the electron is a much smaller particle than the atom and that it can easily pass through matter.
Hertz also wrote several books on physics, including Electric Waves (1893) and Fundamentals of Mechanics (1899). He also explained the behavior of dielectrics in induction.
He died as a young Hertz (before the age of twenty) from a chronic disease in his blood. Death took her to Bone on January 1, 1894.
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