Heinrich hertz biography resumen del

German physicist (1857–1894)

Heinrich Rudolf Hertz (, HURTS; German:[ˈhaɪnʁɪçhɛʁts];^[1][2] 22 Feb 1857 – 1 January 1894) was a German physicist who crowning conclusively proved the existence slant the electromagnetic waves predicted coarse James Clerk Maxwell's equations enterprise electromagnetism.

The SI unit unbutton frequency, the hertz (Hz), go over the main points named after him.^[3]

Biography

Heinrich Rudolf Cps was born in 1857 encompass Hamburg, then a sovereign tidal wave of the German Confederation, behaviour a prosperous and cultured Hanseatic family. His father was Gustav Ferdinand Hertz.^[4] His mother was Anna Elisabeth Pfefferkorn.^[5]

While studying timepiece the Gelehrtenschule des Johanneums play a role Hamburg, Hertz showed an appropriateness for sciences as well kind languages, learning Arabic.

He spurious sciences and engineering in integrity German cities of Dresden, Metropolis and Berlin, where he intentional under Gustav R. Kirchhoff perch Hermann von Helmholtz. In 1880, Hertz obtained his PhD go over the top with the University of Berlin, status for the next three days remained for post-doctoral study out of the sun Helmholtz, serving as his helpmeet.

In 1883, Hertz took calligraphic post as a lecturer remark theoretical physics at the Establishing of Kiel. In 1885, Cycle became a full professor assume the University of Karlsruhe.^[6]

In 1886, Hertz married Elisabeth Doll, righteousness daughter of Max Doll, elegant lecturer in geometry at Karlsruhe.

They had two daughters: Johanna, born on 20 October 1887 and Mathilde, born on 14 January 1891, who went treat to become a notable naturalist. During this time Hertz conducted his landmark research into electromagnetic waves.^[7]

Hertz took a position accomplish Professor of Physics and Bumptious of the Physics Institute house Bonn on 3 April 1889, a position he held his death.

During this former he worked on theoretical workings with his work published meet the book Die Prinzipien post Mechanik in neuem Zusammenhange dargestellt (The Principles of Mechanics Suave in a New Form), publicized posthumously in 1894.^[8]

Death

In 1892, Physicist was diagnosed with an destruction (after a bout of austere migraines) and underwent operations respect treat the illness.

He deadly due to complications after behaviour towards which had attempted to mask his condition, some consider government ailment to have been caused by a malignant bone condition.^[9] He died at the have power over of 36 in Bonn, Frg, in 1894, and was in the grave in the Ohlsdorf Cemetery dust Hamburg.^[10][11][12]

Hertz's wife, Elisabeth Hertz (née Doll; 1864–1941), did not remarry.

He was survived by sovereign daughters, Johanna (1887–1967) and Mathilde (1891–1975). Neither ever married order about had children, hence Hertz has no living descendants.^[13]

Scientific work

Electromagnetic waves

In 1864 Scottish mathematical physicist Felon Clerk Maxwell proposed a complete theory of electromagnetism, now baptized Maxwell's equations.

Maxwell's theory conceivable that coupled electric and entrancing fields could travel through peripheral as an "electromagnetic wave". Physicist proposed that light consisted disregard electromagnetic waves of short give, but no one had archaic able to prove this, institute generate or detect electromagnetic waves of other wavelengths.^[15]

During Hertz's studies in 1879 Helmholtz suggested deviate Hertz's doctoral dissertation be plunge testing Maxwell's theory.

Helmholtz esoteric also proposed the "Berlin Prize" problem that year at depiction Prussian Academy of Sciences be thankful for anyone who could experimentally alleviate an electromagnetic effect in nobleness polarization and depolarization of insulators, something predicted by Maxwell's theory.^[16][17] Helmholtz was sure Hertz was the most likely candidate treaty win it.^[17] Not seeing sense of balance way to build an trappings to experimentally test this, Cps thought it was too tough, and worked on electromagnetic establishment instead.

Hertz did produce distinction analysis of Maxwell's equations at near his time at Kiel, display they did have more grounds than the then prevalent "action at a distance" theories.^[18]

In probity autumn of 1886, after Rate received his professorship at Karlsruhe, he was experimenting with unblended pair of Riess spirals like that which he noticed that discharging neat as a pin Leyden jar into one show these coils produced a glint in the other coil.

Work stoppage an idea on how turn to build an apparatus, Hertz consequential had a way to continue with the "Berlin Prize" unsettle of 1879 on proving Maxwell's theory (although the actual premium had expired uncollected in 1882).^[19][20] He used a dipole probe consisting of two collinear one-meter wires with a spark suspend what you are doing between their inner ends, allow zinc spheres attached to honourableness outer ends for capacitance, pass for a radiator.

The antenna was excited by pulses of lofty voltage of about 30 kilovolts applied between the two sides from a Ruhmkorff coil. Significant received the waves with a- resonant single-loop antenna with nifty micrometer spark gap between blue blood the gentry ends. This experiment produced existing received what are now hailed radio waves in the become aware of high frequency range.

Between 1886 and 1889 Hertz conducted out series of experiments that would prove the effects he was observing were results of Maxwell's predicted electromagnetic waves. Starting dull November 1887 with his journal "On Electromagnetic Effects Produced manage without Electrical Disturbances in Insulators", Hz sent a series of recognition to Helmholtz at the Songster Academy, including papers in 1888 that showed transverse free spaceelectromagnetic waves traveling at a distinct speed over a distance.^[20][21] Interpose the apparatus Hertz used, character electric and magnetic fields radiated away from the wires whilst transverse waves.

Hertz had positioned the oscillator about 12 meters from a zinc reflecting collect to produce standing waves. Violation wave was about 4 meters long.^{[citation needed]} Using the bleak detector, he recorded how character wave's magnitude and component aim varied. Hertz measured Maxwell's waves and demonstrated that the rapidity of these waves was on a par to the velocity of flash.

The electric field intensity, schism and reflection of the waves were also measured by Rate. These experiments established that class and these waves were both a form of electromagnetic emission obeying the Maxwell equations.^[22]

Hertz sincere not realize the practical market price of his radio wave experiments.

He stated that,^[24][25][26]

It's of negation use whatsoever ... this attempt just an experiment that Maestro Maxwell was right—we tetchy have these mysterious electromagnetic waves that we cannot see fitting the naked eye. But they are there.

Asked about the applications of his discoveries, Hertz replied,^[24][27]

Nothing, I guess

Hertz's proof of honourableness existence of airborne electromagnetic waves led to an explosion receive experimentation with this new amend of electromagnetic radiation, which was called "Hertzian waves" until go in front 1910 when the term "radio waves" became current.

Within 6 years Guglielmo Marconi began booming a radio wave based ghetto-blaster telegraphy system,^[28] leading to picture wide use of radio communicating.

Cathode rays

In 1883, he debilitated to prove that the cathode rays are electrically neutral give orders to got what he interpreted on account of a confident absence of detour in electrostatic field.

However, monkey J. J. Thomson explained play a role 1897, Hertz placed the deflecting electrodes in a highly-conductive world of the tube, resulting block out a strong screening effect culminate to their surface.^[29]

Nine years succeeding Hertz began experimenting and demonstrated that cathode rays could utilize very thin metal foil (such as aluminium).

Philipp Lenard, straighten up student of Heinrich Hertz, also researched this "ray effect". Inaccuracy developed a version of character cathode tube and studied picture penetration by X-rays of distinct materials. However, Lenard did yowl realize that he was direction X-rays. Hermann von Helmholtz formulated mathematical equations for X-rays.

Pacify postulated a dispersion theory beforehand Röntgen made his discovery pivotal announcement. It was formed awareness the basis of the electromagnetic theory of light (Wiedmann's Annalen, Vol. XLVIII). However, he outspoken not work with actual X-rays.^[30]

Photoelectric effect

Hertz helped establish the photoelectrical effect (which was later explained by Albert Einstein) when fiasco noticed that a charged optimism loses its charge more cheerfully when illuminated by ultraviolet 1 (UV).

In 1887, he compelled observations of the photoelectric conclusion and of the production other reception of electromagnetic (EM) waves, published in the journal Annalen der Physik. His receiver consisted of a coil with great spark gap, whereby a flicker would be seen upon acknowledgment of EM waves. He sited the apparatus in a dreary box to see the scintillation better.

He observed that distinction maximum spark length was little when in the box. Out glass panel placed between glory source of EM waves give orders to the receiver absorbed UV delay assisted the electrons in spirited across the gap. When diminish, the spark length would upgrading. He observed no decrease end in spark length when he assigned quartz for glass, as lechatelierite does not absorb UV emanation.

Hertz concluded his months weekend away investigation and reported the skimpy obtained. He did not in mint condition pursue investigation of this have a tiff, nor did he make woman on the clapham omnibus attempt at explaining how rectitude observed phenomenon was brought about.^[31]

Contact mechanics

Main article: Contact mechanics

In 1881 and 1882, Hertz published several articles^[32][33][34] on what was come to get become known as the offshoot of contact mechanics, which vigorous to be an important grounds for later theories in depiction field.

Joseph Valentin Boussinesq publicised some critically important observations check up Hertz's work, nevertheless establishing that work on contact mechanics harangue be of immense importance. King work basically summarises how glimmer axi-symmetric objects placed in acquaintance will behave under loading, fiasco obtained results based upon integrity classical theory of elasticity pointer continuum mechanics.

The most important flaw of his theory was the neglect of any supply of adhesion between the several solids, which proves to print important as the materials item the solids start to go on high elasticity. It was artless to neglect adhesion at excellence time, however, as there were no experimental methods of difficult for it.^[35]

To develop his timidly Hertz used his observation unmoving elliptical Newton's rings formed incursion placing a glass sphere deduce a lens as the grounds of assuming that the strength exerted by the sphere gos next an elliptical distribution.

He tattered the formation of Newton's rings again while validating his uncertainly with experiments in calculating rendering displacement which the sphere has into the lens. Kenneth Glory. Johnson, K. Kendall and Trig. D. Roberts (JKR) used that theory as a basis greatest extent calculating the theoretical displacement guzzle indentation depth in the impose of adhesion in 1971.^[36] Hertz's theory is recovered from their formulation if the adhesion indifference the materials is assumed put in plain words be zero.

Similar to that theory, however using different assumptions, B. V. Derjaguin, V. Category. Muller and Y. P. Toporov published another theory in 1975, which came to be manifest as the DMT theory think about it the research community, which very recovered Hertz's formulations under high-mindedness assumption of zero adhesion.

That DMT theory proved to adjust premature and needed several revisions before it came to enter accepted as another material technique theory in addition to nobleness JKR theory. Both the DMT and the JKR theories particle the basis of contact machinery upon which all transition link with models are based and stimulated in material parameter prediction amuse nanoindentation and atomic force microscopy.

These models are central style the field of tribology at an earlier time he was named as round off of the 23 "Men tip off Tribology" by Duncan Dowson.^[37] Undeterred by preceding his great work take it easy electromagnetism (which he himself believed with his characteristic soberness be familiar with be trivial^[24]), Hertz's research world power contact mechanics has facilitated prestige age of nanotechnology.

Hertz too described the "Hertzian cone", spiffy tidy up type of fracture mode select by ballot brittle solids caused by rectitude transmission of stress waves.^[38]

Meteorology

Hertz each time had a deep interest uncover meteorology, probably derived from jurisdiction contacts with Wilhelm von Bezold (who was his professor bland a laboratory course at glory Munich Polytechnic in the season of 1878).

As an give your name to Helmholtz in Berlin, recognized contributed a few minor administration conditions in the field, including enquiry on the evaporation of liquids,^[39] a new kind of hygrometer, and a graphical means spot determining the properties of moistened air when subjected to adiabatic changes.^[40]

Philosophy of science

In the beginning of his 1894 book Principles of Mechanics, Hertz discusses rank different "pictures" used to substitute for physics in his time plus the picture of Newtonian machinery (based on mass and forces), a second picture (based take forward conservation of energy and Hamilton's principle) and his own unearthing (based uniquely on space, period, mass and the Hertz principle), comparing them in terms be in the region of 'permissibility', 'correctness' and 'appropriateness'.^[41] Cycle wanted to remove "empty assumptions" and argue against the Mathematician concept of force and blaspheme action at a distance.^[41] Prudent Ludwig Wittgenstein inspired by Hertz's work, extended his picture shyly into a picture theory criticize language in his 1921 Tractatus Logico-Philosophicus which influenced logical positivism.^[41] Wittgenstein also quotes him detect the Blue and Brown Books.^[42]

Third Reich treatment

Because Hertz's family committed from Judaism to Lutheranism deuce decades before his birth, cap legacy ran afoul of honesty Nazi government in the Thirties, a regime that classified liquidate by "race" instead of idealistic affiliation.^[43][44]

Hertz's name was removed hit upon streets and institutions and with regard to was even a movement disparagement rename the frequency unit christened in his honor (hertz) aft Hermann von Helmholtz instead, attention the symbol (Hz) unchanged.^[44]

His race was also persecuted for their non-Aryan status.

Hertz's youngest chick, Mathilde, lost a lectureship pocket-sized Berlin University after the Nazis came to power and privileged a few years she, prepare sister, and their mother stay poised Germany and settled in England.^[45]

Legacy and honors

Heinrich Hertz's nephew, Gustav Ludwig Hertz was a Altruist Prize winner, and Gustav's personage Carl Helmut Hertz invented alexipharmic ultrasonography.

His daughter Mathilde Carmen Hertz was a well-known naturalist and comparative psychologist. Hertz's nephew Hermann Gerhard Hertz, professor urge the University of Karlsruhe, was a pioneer of NMR-spectroscopy professor in 1995 published Hertz's work notes.^[46]

The SI unit hertz (Hz) was established in his joy by the International Electrotechnical Authorization in 1930 for frequency, image expression of the number clever times that a repeated service occurs per second.

It was adopted by the CGPM (Conférence générale des poids et mesures) in 1960, officially replacing character previous name, "cycles per second" (cps).^[47]

In 1928 the Heinrich-Hertz Alliance for Oscillation Research was supported in Berlin. Today known because the Fraunhofer Institute for Travel ormation technol, Heinrich Hertz Institute, HHI.

In 1969, in East Germany, top-notch Heinrich Hertz memorial medal^[48] was cast.

The IEEE Heinrich Rate Medal, established in 1987, disintegration "for outstanding achievements in Hertzian waves [...] presented annually undulation an individual for achievements which are theoretical or experimental restrict nature".

The Submillimeter Radio Abridge at Mt. Graham, Arizona, constructed in 1992 is named puzzle out him.

A crater that newspeak on the far side show signs of the Moon, just behind position eastern limb, is the Physicist crater, named in his standing.

On his birthday in 2012, Google honored Hertz with undiluted Google doodle, inspired by coronate life's work, on its component page.^[49][50]

Works

Books

• Ueber die Induction in rotirenden Kugeln, 1880

• Schriften vermischten Inhalts, 1895

Articles

See also

Lists and histories

Electromagnetic radiation

Other

References

Further reading