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Ernst Florens Friedrich Chladni (, , ; 30 November 1756 – 3 April 1827) was a
German German(s) may refer to: * Germany (of or related to) **Germania (historical use) * Germans, citizens of Germany, people of German ancestry, or native speakers of the German language ** For citizens of Germany, see also German nationality law **Ge ...
physicist A physicist is a scientist who specializes in the field of physics, which encompasses the interactions of matter and energy at all length and time scales in the physical universe. Physicists generally are interested in the root or ultimate cau ...
and
music Music is generally defined as the art of arranging sound to create some combination of form, harmony, melody, rhythm or otherwise expressive content. Exact definitions of music vary considerably around the world, though it is an aspe ...
ian. His most important work, for which he is sometimes labeled as the father of
acoustics Acoustics is a branch of physics that deals with the study of mechanical waves in gases, liquids, and solids including topics such as vibration, sound, ultrasound and infrasound. A scientist who works in the field of acoustics is an acousticia ...
, included research on vibrating plates and the calculation of the
speed of sound The speed of sound is the distance travelled per unit of time by a sound wave as it propagates through an elastic medium. At , the speed of sound in air is about , or one kilometre in or one mile in . It depends strongly on temperature as we ...
for different gases. He also undertook pioneering work in the study of
meteorite A meteorite is a solid piece of debris from an object, such as a comet, asteroid, or meteoroid, that originates in outer space and survives its passage through the atmosphere to reach the surface of a planet or moon. When the original object ...
s and is regarded by some as the father of
meteoritics Meteoritics is the science that deals with meteors, meteorites, and meteoroids. It is closely connected to cosmochemistry, mineralogy and geochemistry. A specialist who studies meteoritics is known as a ''meteoriticist''. Scientific research in ...
.


Early life

Although Chladni was born in
Wittenberg Wittenberg ( , ; Low Saxon: ''Wittenbarg''; meaning ''White Mountain''; officially Lutherstadt Wittenberg (''Luther City Wittenberg'')), is the fourth largest town in Saxony-Anhalt, Germany. Wittenberg is situated on the River Elbe, north of ...
in
Saxony Saxony (german: Sachsen ; Upper Saxon German, Upper Saxon: ''Saggsn''; hsb, Sakska), officially the Free State of Saxony (german: Freistaat Sachsen, links=no ; Upper Saxon: ''Freischdaad Saggsn''; hsb, Swobodny stat Sakska, links=no), is a ...
, his family originated from
Kremnica Kremnica (; german: Kremnitz, hu, Körmöcbánya) is a town in central Slovakia. It has around 5,300 inhabitants. The well-preserved medieval town built above important gold mines is the site of the oldest still-working mint in the world. Name ...
, then part of the
Kingdom of Hungary The Kingdom of Hungary was a monarchy in Central Europe that existed for nearly a millennium, from the Middle Ages into the 20th century. The Principality of Hungary emerged as a Christian kingdom upon the Coronation of the Hungarian monarch, c ...
and today a mining town in central
Slovakia Slovakia (; sk, Slovensko ), officially the Slovak Republic ( sk, Slovenská republika, links=no ), is a landlocked country in Central Europe. It is bordered by Poland to the north, Ukraine to the east, Hungary to the south, Austria to the ...
. Chladni has therefore been identified as
German German(s) may refer to: * Germany (of or related to) **Germania (historical use) * Germans, citizens of Germany, people of German ancestry, or native speakers of the German language ** For citizens of Germany, see also German nationality law **Ge ...
, Hungarian and Slovak. Chladni came from an educated family of academics and learned men. Chladni's great-grandfather, the
Lutheran Lutheranism is one of the largest branches of Protestantism, identifying primarily with the theology of Martin Luther, the 16th-century German monk and reformer whose efforts to reform the theology and practice of the Catholic Church launched ...
clergyman Georg Chladni (1637–1692), had left Kremnica in 1673 during the
Counter Reformation The Counter-Reformation (), also called the Catholic Reformation () or the Catholic Revival, was the period of Catholic resurgence that was initiated in response to the Protestant Reformation. It began with the Council of Trent (1545–1563) a ...
. Chladni's grandfather, Martin Chladni (1669–1725), was also a Lutheran theologian and, in 1710, became professor of
theology Theology is the systematic study of the nature of the divine and, more broadly, of religious belief. It is taught as an academic discipline, typically in universities and seminaries. It occupies itself with the unique content of analyzing th ...
at the
University of Wittenberg Martin Luther University of Halle-Wittenberg (german: Martin-Luther-Universität Halle-Wittenberg), also referred to as MLU, is a public, research-oriented university in the cities of Halle and Wittenberg and the largest and oldest university i ...
. He was dean of the theology faculty in 1720–1721 and later became the university's
rector Rector (Latin for the member of a vessel's crew who steers) may refer to: Style or title *Rector (ecclesiastical), a cleric who functions as an administrative leader in some Christian denominations *Rector (academia), a senior official in an edu ...
. Chladni's uncle, Justus Georg Chladni (1701–1765), was a law professor at the university. Another uncle, Johann Martin Chladni (1710–1759), was a theologian, a historian and a professor at the
University of Erlangen A university () is an institution of higher (or tertiary) education and research which awards academic degrees in several academic disciplines. Universities typically offer both undergraduate and postgraduate programs. In the United States, th ...
and the
University of Leipzig Leipzig University (german: Universität Leipzig), in Leipzig in Saxony, Germany, is one of the world's oldest universities and the second-oldest university (by consecutive years of existence) in Germany. The university was founded on 2 December ...
. Chladni's father, Ernst Martin Chladni (1715–1782), was a law professor and rector of the University of Wittenberg. He had joined the law faculty there in 1746. Chladni's mother was Johanna Sophia and he was an
only child An only child is a person with no siblings, by birth or adoption. Children who have half-siblings, step-siblings, or have never met their siblings, either living at the same house or at a different house—especially those who were born consider ...
. His father disapproved of his son's interest in science and insisted that Chladni become a lawyer.


Career

Chladni studied law and philosophy in Wittenberg and Leipzig, obtaining a law degree from the University of Leipzig in 1782. That same year, his father died and he turned to physics in earnest.P. 101 Oxford Dictionary of Scientists – Oxford University Press – 1999 He gave lectures on law, mathematics, and natural sciences at the University of Wittenberg from 1783 to 1792. During this time, he began his first experiments with acoustics.


Chladni figures

One of Chladni's best-known achievements was inventing a technique to show the various modes of vibration on a rigid surface, known as Chladni figures or Chladni patterns due to the various shapes or patterns created by various modes. When resonating, a plate or membrane is divided into regions that vibrate in opposite directions, bounded by lines where no vibration occurs ( nodal lines). Chladni repeated the pioneering experiments of
Robert Hooke Robert Hooke FRS (; 18 July 16353 March 1703) was an English polymath active as a scientist, natural philosopher and architect, who is credited to be one of two scientists to discover microorganisms in 1665 using a compound microscope that ...
who, on 8 July, 1680, had observed the nodal patterns associated with the vibrations of glass plates. Hooke ran a violin bow along the edge of a plate covered with flour and saw the nodal patterns emerge. Chladni's technique, first published in 1787 in his book ''Entdeckungen über die Theorie des Klanges'' ("Discoveries in the Theory of Sound"), consisted of drawing a bow over a piece of metal whose surface was lightly covered with sand. The plate was bowed until it reached resonance, when the vibration causes the sand to move and concentrate along the nodal lines where the surface is still, outlining the nodal lines. The patterns formed by these lines are what are now called ''Chladni figures''. Similar nodal patterns can also be found by assembling microscale materials on
Faraday waves Faraday waves, also known as Faraday ripples, named after Michael Faraday (1791–1867), are nonlinear standing waves that appear on liquids enclosed by a vibrating receptacle. When the vibration frequency exceeds a critical value, the flat hydro ...
. Chladni had visited the Paris Academy in 1808 and had demonstrated the vibration patterns before an audience that included not only the leading French scientists but
Napoleon Napoleon Bonaparte ; it, Napoleone Bonaparte, ; co, Napulione Buonaparte. (born Napoleone Buonaparte; 15 August 1769 – 5 May 1821), later known by his regnal name Napoleon I, was a French military commander and political leader wh ...
himself; Napoleon set a prize for the best mathematical explanation.
Sophie Germain Marie-Sophie Germain (; 1 April 1776 – 27 June 1831) was a French mathematician, physicist, and philosopher. Despite initial opposition from her parents and difficulties presented by society, she gained education from books in her father's lib ...
's answer, although rejected due to flaws, was the only entry with the correct approach. Variations of this technique are still commonly used in the design and construction of acoustic instruments such as
violin The violin, sometimes known as a '' fiddle'', is a wooden chordophone ( string instrument) in the violin family. Most violins have a hollow wooden body. It is the smallest and thus highest-pitched instrument ( soprano) in the family in regu ...
s,
guitar The guitar is a fretted musical instrument that typically has six strings. It is usually held flat against the player's body and played by strumming or plucking the strings with the dominant hand, while simultaneously pressing selected string ...
s, and
cello The cello ( ; plural ''celli'' or ''cellos'') or violoncello ( ; ) is a bowed (sometimes plucked and occasionally hit) string instrument of the violin family. Its four strings are usually tuned in perfect fifths: from low to high, C2, G2, ...
s. Since the 20th century, it has become more common to place a loudspeaker driven by an electronic
signal generator A signal generator is one of a class of electronic devices that generates electrical signals with set properties of amplitude, frequency, and wave shape. These generated signals are used as a stimulus for electronic measurements, typically used i ...
over or under the plate to achieve a more accurate adjustable frequency. In
quantum mechanics Quantum mechanics is a fundamental theory in physics that provides a description of the physical properties of nature at the scale of atoms and subatomic particles. It is the foundation of all quantum physics including quantum chemistry, ...
, Chladni figures ("nodal patterns") are known to be related to the solutions of the
Schrödinger equation The Schrödinger equation is a linear partial differential equation that governs the wave function of a quantum-mechanical system. It is a key result in quantum mechanics, and its discovery was a significant landmark in the development of the ...
for one-electron atoms, and the mathematics describing them was used by
Erwin Schrödinger Erwin Rudolf Josef Alexander Schrödinger (, ; ; 12 August 1887 – 4 January 1961), sometimes written as or , was a Nobel Prize-winning Austrian physicist with Irish citizenship who developed a number of fundamental results in quantum theory ...
to arrive at the understanding of electron orbitals.


Musical instruments

Since at least 1738, a musical instrument called a ''Glasspiel'' or ''verrillon'', created by filling beer glasses with varying amounts of water, was popular in Europe. The beer glasses were struck by wooden mallets shaped like spoons to produce "church and other solemn music".
Benjamin Franklin Benjamin Franklin ( April 17, 1790) was an American polymath who was active as a writer, scientist, inventor, statesman, diplomat, printer, publisher, and political philosopher. Encyclopædia Britannica, Wood, 2021 Among the leading inte ...
was sufficiently impressed by a verrillon performance on a visit to London in 1757 that he created his own instrument, the
glass armonica The glass harmonica, also known as the glass armonica, glass harmonium, bowl organ, hydrocrystalophone, or simply the armonica or harmonica (derived from , ''harmonia'', the Greek word for harmony), is a type of musical instrument that uses a ...
, in 1762. Franklin's armonica inspired several other instruments, including two created by Chladni. In 1791, Chladni invented the musical instrument called the ''euphon'' (not to be confused with the brass instrument
euphonium The euphonium is a medium-sized, 3 or 4-valve, often compensating, conical-bore, tenor-voiced brass instrument that derives its name from the Ancient Greek word ''euphōnos'', meaning "well-sounding" or "sweet-voiced" ( ''eu'' means "well" ...
), consisting of glass rods of different pitches. Chladni's euphon is the direct ancestor of the modern day musical instrument known as the '' Cristal Baschet''. Chladni also improved on Hooke's "musical cylinder" to produce another instrument, the clavicylinder, in 1799. Chladni travelled throughout Europe with his instruments giving demonstrations."Life and work of E.F.F. Chladni"
D. Ullmann1, ''The European Physical Journal'' – Special Topics, Springer, Berlin / Heidelberg, (Print) (Online), Issue Volume 145, Number 1, June 2007, , pp. 25–32


Contributions to meteoritics

Chladni became interested in meteoritics following a conversation he had with
Georg Christoph Lichtenberg Georg Christoph Lichtenberg (1 July 1742 – 24 February 1799) was a German physicist, satirist, and Anglophile. As a scientist, he was the first to hold a professorship explicitly dedicated to experimental physics in Germany. He is remembered for ...
about a fireball that Lichtenberg supposedly saw in the Gӧttingen sky in November 1791. Inspired by this report, Chladni researched reports of similar phenomena as well as reports of other falling masses across Europe and North America within the last century. Based on the uniformity among these sightings, he concluded that the phenomena of fireballs and falling masses must be genuine. This led him to publish ''Über den Ursprung der von Pallas gefundenen und anderer ihr ähnlicher Eisenmassen und über einige damit in Verbindung stehende Naturerscheinungen'' ("On the Origin of the Iron Masses Found by
Pallas Pallas may refer to: Astronomy * 2 Pallas asteroid ** Pallas family, a group of asteroids that includes 2 Pallas * Pallas (crater), a crater on Earth's moon Mythology * Pallas (Giant), a son of Uranus and Gaia, killed and flayed by Athena * Pa ...
and Others Similar to it, and on Some Associated Natural Phenomena") in 1794. In this book he proposed that
meteorite A meteorite is a solid piece of debris from an object, such as a comet, asteroid, or meteoroid, that originates in outer space and survives its passage through the atmosphere to reach the surface of a planet or moon. When the original object ...
s have an extraterrestrial origin. He argued that this would explain the high speeds of the falling masses as well as linking the masses to the fireballs; they glow intensely bright as they enter the Earth's atmosphere. He hypothesized that these meteorites were chunks of material that had either never been consolidated in the formation of larger masses or were debris from the formation and destruction of
planets A planet is a large, rounded astronomical body that is neither a star nor its remnant. The best available theory of planet formation is the nebular hypothesis, which posits that an interstellar cloud collapses out of a nebula to create a young ...
. This was a controversial statement at the time, since meteorites were thought to be of volcanic origin. Additionally, his claims challenged the established belief that nothing existed beyond the moon except for other stars and planets. Indeed, this supposed emptiness of space had fascinated Chladni as a child when he learned about the relatively large distance between Mars and Jupiter, where the
Asteroid Belt The asteroid belt is a torus-shaped region in the Solar System, located roughly between the orbits of the planets Jupiter and Mars. It contains a great many solid, irregularly shaped bodies, of many sizes, but much smaller than planets, called ...
is now known to exist. This observation factored into his account for the origins of meteorites. Chladni's book was initially ridiculed by contemporary physicists, including Lichtenberg.Ron Cowen. “After the Fall.” ''Science News'', vol. 148, no. 16, 1995, pp. 248–249. ''JSTOR'', www.jstor.org/stable/4018119. Accessed 16 March 2020. Still, his writings sparked a curiosity that eventually led to more researchers supporting his theory. In 1795, a large stony meteorite was observed during its fall to Earth at a cottage near Wold Newton in
Yorkshire Yorkshire ( ; abbreviated Yorks), formally known as the County of York, is a Historic counties of England, historic county in northern England and by far the largest in the United Kingdom. Because of its large area in comparison with other Eng ...
,
England England is a country that is part of the United Kingdom. It shares land borders with Wales to its west and Scotland to its north. The Irish Sea lies northwest and the Celtic Sea to the southwest. It is separated from continental Europe b ...
and a piece of it, known as the
Wold Cottage meteorite The Wold Cottage meteorite (also called the Wold Newton meteorite) fell near Wold Cottage farm in 1795, a few miles away from the village of Wold Newton in Yorkshire, England. The meteorite The stone fell at around 3 o'clock, on 13 December 17 ...
, was given to the
British British may refer to: Peoples, culture, and language * British people, nationals or natives of the United Kingdom, British Overseas Territories, and Crown Dependencies. ** Britishness, the British identity and common culture * British English, ...
chemist A chemist (from Greek ''chēm(ía)'' alchemy; replacing ''chymist'' from Medieval Latin ''alchemist'') is a scientist trained in the study of chemistry. Chemists study the composition of matter and its properties. Chemists carefully describe th ...
Edward Howard who, along with French
mineral In geology and mineralogy, a mineral or mineral species is, broadly speaking, a solid chemical compound with a fairly well-defined chemical composition and a specific crystal structure that occurs naturally in pure form.John P. Rafferty, ed. ( ...
ogist Jacques de Bournon, carefully analyzed its composition and concluded that an extraterrestrial origin was likely, noting that the sample bore a strong resemblance to a sample of a meteorite from an early meteor shower in
Siena, Italy Siena ( , ; lat, Sena Iulia) is a city in Tuscany, Italy. It is the capital of the province of Siena. The city is historically linked to commercial and banking activities, having been a major banking center until the 13th and 14th centuri ...
. Although that event had been attributed to an eruption of
Mount Vesuvius Mount Vesuvius ( ; it, Vesuvio ; nap, 'O Vesuvio , also or ; la, Vesuvius , also , or ) is a somma-stratovolcano located on the Gulf of Naples in Campania, Italy, about east of Naples and a short distance from the shore. It is one of s ...
a few hundred kilometers away, no similar volcanoes exists within the same range of Wold Newton, with the closest being
Hekla Hekla (), or Hecla, is a stratovolcano in the south of Iceland with a height of . Hekla is one of Iceland's most active volcanoes; over 20 eruptions have occurred in and around the volcano since 874. During the Middle Ages, the Icelandic Norse ...
in
Iceland Iceland ( is, Ísland; ) is a Nordic island country in the North Atlantic Ocean and in the Arctic Ocean. Iceland is the most sparsely populated country in Europe. Iceland's capital and largest city is Reykjavík, which (along with its s ...
. In 1803, the physicist and
astronomer An astronomer is a scientist in the field of astronomy who focuses their studies on a specific question or field outside the scope of Earth. They observe astronomical objects such as stars, planets, natural satellite, moons, comets and galaxy, g ...
Jean Baptiste Biot Jean-Baptiste Biot (; ; 21 April 1774 – 3 February 1862) was a French physicist, astronomer, and mathematician who co-discovered the Biot–Savart law of magnetostatics with Félix Savart, established the reality of meteorites, made an early b ...
was commissioned by the French Minister of the Interior to investigate a meteor shower over L'Aigle in northern France that had peppered the town with thousands of meteorite fragments. Unlike Chladni's book and the scientific publication by Howard and de Bournon, Biot's lively report became popular and persuaded more people to take Chladni's insights seriously. Chladni's insights have led some in the field to call him the "father of meteoritics" while others have been more conservative with their appraisal of Chladni's contributions to the field. Chladni continued to develop his record of meteorite sightings throughout the next several decades as well as amassing a collection of meteorite samples. He donated this collection to the Mineralogical Museum of Berlin University in 1827 and it now resides in the Museum of Natural History at Humboldt University of Berlin. A mineral, first described in 1993 from the Carlton (IIICD) iron meteorite, was named chladniite in his honor.


Other work

Chladni discovered
Chladni's law Chladni's law, named after Ernst Chladni, relates the frequency of modes of vibration for flat circular surfaces with fixed center as a function of the numbers ''m'' of diametric (linear) nodes and ''n'' of radial (circular) nodes. It is stated a ...
, a simple algebraic relation for approximating the modal frequencies of the free oscillations of plates and other bodies. Chladni estimated sound velocities in different gases by placing those gases in an organ pipe and measuring the characteristics of the sounds that emerged when the pipe was played.Chladni, Ernst (1756–1827)
''Eric Weisstein's World of Scientific Biography''.
This built on work on measuring the speed of sound in air that
Pierre Gassendi Pierre Gassendi (; also Pierre Gassend, Petrus Gassendi; 22 January 1592 – 24 October 1655) was a French philosopher, Catholic priest, astronomer, and mathematician. While he held a church position in south-east France, he also spent much tim ...
began in 1635.


Death

Chladni died on 3 April 1827, in Breslau,
Lower Silesia Lower Silesia ( pl, Dolny Śląsk; cz, Dolní Slezsko; german: Niederschlesien; szl, Dolny Ślōnsk; hsb, Delnja Šleska; dsb, Dolna Šlazyńska; Silesian German: ''Niederschläsing''; la, Silesia Inferior) is the northwestern part of the ...
, then part of the
Kingdom of Prussia The Kingdom of Prussia (german: Königreich Preußen, ) was a German kingdom that constituted the state of Prussia between 1701 and 1918.Marriott, J. A. R., and Charles Grant Robertson. ''The Evolution of Prussia, the Making of an Empire''. Re ...
and today the city of Wrocław in southwestern
Poland Poland, officially the Republic of Poland, is a country in Central Europe. It is divided into 16 administrative provinces called voivodeships, covering an area of . Poland has a population of over 38 million and is the fifth-most populous ...
.


Bibliography

* ''Entdeckungen über die Theorie des Klanges''
Leipzig 1787.
''Die Akustik''
Leipzig 1802. French translation: ''Traite d’acoustique'', Paris 1809. Also in ''Neue Beiträge zur Akustik'', Leipzig 1817. * ''Beiträge zur praktischen Akustik und zur Lehre vom Instrumentbau'', Leipzig 1821 (). * , Leipzig/Riga 1794.
''Über Feuermeteore''
Vienna 1820.
''Über die Hervorbringung der menschlichen Sprachlaute''
Leipzig 1824.
''Kurze Übersicht der Schall und Klanglehre, nebst einem Anhange die Entwickelung und Anordnung der Tonverhältnisse betreffend''
Mainz 1827.


See also

*
Bessel function Bessel functions, first defined by the mathematician Daniel Bernoulli and then generalized by Friedrich Bessel, are canonical solutions of Bessel's differential equation x^2 \frac + x \frac + \left(x^2 - \alpha^2 \right)y = 0 for an arbitrary ...
s *
Hans Jenny (cymatics) Hans Jenny (16 August 1904, Basel – 23 June 1972, Dornach) was a physician and natural scientist who coined the term cymatics to describe acoustic effects of sound wave phenomena. Life and career Jenny was born in Basel, Switzerland. After compl ...
*
Alexander Lauterwasser Alexander Lauterwasser (born 1951 in Überlingen) is a German researcher and photographer who based his work on work done by Ernst Chladni and Hans Jenny in the field of Cymatics. In 2002, Lauterwasser published his book ''Wasser Klang Bilder ...
, a photographer who uses Chladni's work when creating images of liquid surfaces *
Tritare A tritare is an experimental guitar invented in 2003 by mathematicians Samuel Gaudet and Claude Gauthier of the Université de Moncton of a family of stringed instruments which use Y-shaped strings, instead of the usual linear strings. Instrument ...
, a guitar causing particular forms of Chladni figures *
Vibrations of a circular membrane A two-dimensional elastic membrane under tension can support transverse vibrations. The properties of an idealized drumhead can be modeled by the vibrations of a circular membrane of uniform thickness, attached to a rigid frame. Due to the ph ...


References


Further reading

* Jackson, Myles W. (2006) ''Harmonious Triads: Physicists, Musicians, and Instrument Makers in Nineteenth-Century Germany'' (MIT Press). * * Rossing T. D. (1982) ''Chladni's Law for Vibrating Plates'', American Journal of Physics 50, 271–274


External links


Short biography, bibliography, and links on digitized sources
in the
Virtual Laboratory The online project Virtual Laboratory. Essays and Resources on the Experimentalization of Life, 1830-1930, located at the Max Planck Institute for the History of Science, is dedicated to research in the history of the experimentalization of life. T ...
of the
Max Planck Institute for the History of Science The Max Planck Institute for the History of Science (German: Max-Planck-Institut für Wissenschaftsgeschichte) is a scientific research institute founded in March 1994. It is dedicated to addressing fundamental questions of the history of knowledg ...

''Die Akustik''
1802 by Ernst Chladni at Universities of Strasbourg * (Accessed 5/31/08) * (Accessed 5/18/14)

* ttps://web.archive.org/web/20051218024846/http://www.physics.montana.edu/demonstrations/video/3_oscillationandwaves/demos/chladniplates.html Chladni plates
Electromagnetically driven Chladni plate





An explanation on how to construct a Chladni plate for the classroom
* Other pictures of Chladni can be viewed a
this site
and at th
Science and Society Picture Library
*
Ernst Chladni at Monoskop.org
{{DEFAULTSORT:Chladni, Ernst 1756 births 1827 deaths 18th-century German physicists People from the Electorate of Saxony Scientists from Wittenberg German people of Slovak descent Meteorite researchers 19th-century German physicists Articles containing video clips