Heinrich Rudolf Hertz (February 22, 1857 - January 1, 1894), was the German physicist for whom the hertz, the SI unit of frequency, is named. In 1888, he was the first to demonstrate the existence of electromagnetic radiation by building apparatus to produce radio waves.

Hertz was born in Hamburg, Germany, to a Jewish family that had converted to Christianity. His father was an advisor in Hamburg, his mother the daughter of a doctor. While at school, he showed an aptitude for sciences as well as languages, learning Arabic and Sanskrit. He studied sciences and engineering in the German cities of Dresden, Munich and Berlin. He was a student of Gustav R. Kirchhoff and Hermann von Helmholtz. He obtained his PhD in 1880, and remained a pupil of Helmholtz until 1883 when he took a post as a lecturer in theoretical physics at the University of Kiel. In 1885 he became a full professor at the University of Karlsruhe where he discovered electromagnetic waves.

Following Michelson's 1881 experiment (precursor to the 1887 Michelson-Morley experiment) which disproved the existence of luminiferous aether, he reformulated Maxwell's equations to take the new discovery into account. Through experimentation, he proved that electric signals can travel through open air, as had been predicted by James Clerk Maxwell and Michael Faraday, and which is the basis for the invention of radio. He also discovered the photoelectric effect (which was later explained by Albert Einstein) when he noticed that a charged object loses its charge more readily when illuminated by ultraviolet light.

He died in Bonn, Germany.

His nephew Gustav Ludwig Hertz was a Nobel Prize winner, and Gustav's son Carl Hellmuth Hertz invented medical ultrasonography.

See also

People Wilhelm Röntgen Hans Christian �rsted Guglielmo Marconi Gustav Ludwig Hertz Hermann von Helmholtz James Clerk Maxwell Nikola Tesla Wilhelm R�ntgen Lists and histories Electromagnetism timeline Timeline of mechanics and physics List of physicists Radio history Wireless telegraphy List of people on stamps of Germany List of physics topics

Electromagnetic radiation Frequency Hertz Microwave X-ray Photoelectric effect Radar Luminiferous aether Other University of Bonn University of Karlsruhe Radio

External link

• Short biography (http://chem.ch.huji.ac.il/~eugeniik/history/hertz.htm)

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