Franz Emil Melde (March 11, 1832, in Großenlüder near Fulda – March 17, 1901, in

Marburg Marburg (; ) is a college town, university town in the States of Germany, German federal state () of Hesse, capital of the Marburg-Biedenkopf Districts of Germany, district (). The town area spreads along the valley of the river Lahn and has ...

) 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 Academy, academic rank at university, universities and other tertiary education, post-secondary education and research institutions in most countries. Literally, ''professor'' derives from Latin ...

. A graduate of the

University of Marburg The Philipps University of Marburg () is a public research university located in Marburg, Germany. It was founded in 1527 by Philip I, Landgrave of Hesse, which makes it one of Germany's oldest universities and the oldest still operating Prote ...

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 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 acoustician ...

, also making contributions to fields including

fluid mechanics Fluid mechanics is the branch of physics concerned with the mechanics of fluids (liquids, gases, and plasma (physics), plasmas) and the forces on them. Originally applied to water (hydromechanics), it found applications in a wide range of discipl ...

and

meteorology Meteorology is the scientific study of the Earth's atmosphere and short-term atmospheric phenomena (i.e. weather), with a focus on weather forecasting. It has applications in the military, aviation, energy production, transport, agricultur ...

. He began in 1860 as Gerling's assistant at the University's Mathematical and Physical Institute, succeeding him in 1864.

Standing wave In physics, a standing wave, also known as a stationary wave, is a wave that oscillates in time but whose peak amplitude profile does not move in space. The peak amplitude of the wave oscillations at any point in space is constant with respect t ...

s 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 String or strings may refer to: *String (structure), a long flexible structure made from threads twisted together, which is used to tie, bind, or hang other objects Arts, entertainment, and media Films * ''Strings'' (1991 film), a Canadian anim ...

, is used to measure the speed of

transverse wave In physics, a transverse wave is a wave that oscillates perpendicularly to the direction of the wave's advance. In contrast, a longitudinal wave travels in the direction of its oscillations. All waves move energy from place to place without t ...

, and to determine the effect of tension, length, and mass on the transverse waves of a

. 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 ag ...

to periodically vary the tension at twice the

resonance Resonance is a phenomenon that occurs when an object or system is subjected to an external force or vibration whose frequency matches a resonant frequency (or resonance frequency) of the system, defined as a frequency that generates a maximu ...

frequency Frequency is the number of occurrences of a repeating event per unit of time. Frequency is an important parameter used in science and engineering to specify the rate of oscillatory and vibratory phenomena, such as mechanical vibrations, audio ...

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 ...

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 and in 1893 received a silver medal at the Chicago Columbian Exposition.

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 Academic staff of the University of Marburg