Franz Emil Melde (March 11, 1832 in
Großenlüder near Fulda – March 17, 1901 in
Marburg
Marburg ( or ) is a university town in the German federal state (''Bundesland'') of Hesse, capital of the Marburg-Biedenkopf district (''Landkreis''). The town area spreads along the valley of the river Lahn and has a population of approxima ...
) was a German
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
professor
Professor (commonly abbreviated as Prof.) is an academic rank at universities and other post-secondary education and research institutions in most countries. Literally, ''professor'' derives from Latin as a "person who professes". Professors ...
. A graduate of the
University of Marburg
The Philipps University of Marburg (german: Philipps-Universität Marburg) was founded in 1527 by Philip I, Landgrave of Hesse, which makes it one of Germany's oldest universities and the oldest still operating Protestant university in the wor ...
under
Christian Ludwig Gerling
Christian Ludwig Gerling (10 July 1788 – 15 January 1864) studied under Carl Friedrich Gauss, obtaining his doctorate in 1812 for a thesis entitled: ''Methodi proiectionis orthographicae usum ad calculos parallacticos facilitandos explicavit ...
, he later taught there, focusing primarily on
acoustics, also making contributions to fields including
fluid mechanics
Fluid mechanics is the branch of physics concerned with the mechanics of fluids ( liquids, gases, and plasmas) and the forces on them.
It has applications in a wide range of disciplines, including mechanical, aerospace, civil, chemical and ...
and
meteorology
Meteorology is a branch of the atmospheric sciences (which include atmospheric chemistry and physics) with a major focus on weather forecasting. The study of meteorology dates back millennia, though significant progress in meteorology did no ...
. He began in 1860 as Gerling's assistant at the University's Mathematical and Physical Institute, succeeding him in 1864.
Standing waves were first discovered by Melde, who coined the term "standing wave" (''stehende Welle'') around 1860. What is known as "
Melde's experiment", "a lecture-room standby", demonstrates standing waves and their patterns on a
string, is used to measure the speed of
transverse wave
In physics, a transverse wave is a wave whose oscillations are perpendicular to the direction of the wave's advance. This is in contrast to a longitudinal wave which travels in the direction of its oscillations. Water waves are an example of t ...
, and to determine the effect of tension, length, and mass on the transverse waves of a
string. In 1859 Melde generated
parametric oscillations in a string by employing a
tuning fork
A tuning fork is an acoustic resonator in the form of a two-pronged fork with the prongs ( tines) formed from a U-shaped bar of elastic metal (usually steel). It resonates at a specific constant pitch when set vibrating by striking it agains ...
to periodically vary the tension at twice the
resonance
Resonance describes the phenomenon of increased amplitude that occurs when the frequency of an applied Periodic function, periodic force (or a Fourier analysis, Fourier component of it) is equal or close to a natural frequency of the system ...
frequency
Frequency is the number of occurrences of a repeating event per unit of time. It is also occasionally referred to as ''temporal frequency'' for clarity, and is distinct from ''angular frequency''. Frequency is measured in hertz (Hz) which is eq ...
of the
monochord
A monochord, also known as sonometer (see below), is an ancient musical and scientific laboratory instrument, involving one (mono-) string ( chord). The term ''monochord'' is sometimes used as the class-name for any musical stringed instrument h ...
string.
[Scott, Alwyn (2006). ''Encyclopedia of Nonlinear Science'', p.683. Routledge. . "When the tuning fork vibrates and the string is tight, the string performs transverse oscillations with a frequency equal to half the frequency of the tuning fork.]
He was a member of the
Landsmannschaft fraternity. In 1885 he was elected to the
Academy of Sciences Leopoldina
The German National Academy of Sciences Leopoldina (german: Deutsche Akademie der Naturforscher Leopoldina – Nationale Akademie der Wissenschaften), short Leopoldina, is the national academy of Germany, and is located in Halle (Saale). Founded ...
and in 1893 received a silver medal at the
Chicago Columbian Exposition
The World's Columbian Exposition (also known as the Chicago World's Fair) was a world's fair held in Chicago in 1893 to celebrate the 400th anniversary of Christopher Columbus's arrival in the New World in 1492. The centerpiece of the Fair, hel ...
.
Works
*"Ueber einige krumme Flächen, welche von Ebenen parallel einer bestimmten Ebene durchschmittsfigur einen Kegelschnitt liefern" (thesis, 1859)
*"Über Erregung stehender Wellen eines fadenförmigen Körpers", Poggendorffs Annalen der Physik und Chemie (Serie 2), Bd. 109, 1859, S. 193-215
The Production of Standing Waves in Strings"*Das Monochord und Farbenspectrum
he Monochord and Color Spectrum(1864)
*Experimentaluntersuchungen über Blasenbildung im Kreisförmig cylindrischen Röhren
xperimental studies of bubble formation in the Circular cylindrical tubes(1868)
*''Akustik: Fundamentalerscheinungen und Gesetze Einfach Tönender Körper'' (acoustics textbook, 1883)
*''Measurement of Time''
'Theorie und Praxis der astronomischen Zeitbestimmung''(1876)
*''
Chladni's Lebe und Wirken''
'Chladni's Life and Work''(1888)
*"Die wolkenlosen Tage, beobachtet in den Jahren 1866 bis 1894 an der meteorologischen Station Marburg"
Cloudless Days observed at the Meteorological Station at Marburg during the years 1886-1894"(1895)
*Estimation of the Upper Limit of Audibility
References
{{DEFAULTSORT:Melde, Franz
1832 births
1901 deaths
19th-century German physicists
University of Marburg alumni
University of Marburg faculty