Adriaan Fokker
Encyclopedia
Adriaan Daniël Fokker was a Dutch
physicist
and musician
.
Fokker was born in Buitenzorg, Dutch East Indies
(now Bogor
, Indonesia
); he was a cousin of the aeronautical
engineer
Anthony Fokker
. He studied mining engineering
at the Delft University of Technology
and physics
at the University of Leiden
with Hendrik Lorentz
, where he earned his doctorate
in 1913. He continued his studies with Albert Einstein
, Ernest Rutherford
and William Bragg
. In his 1913 thesis, he derived the Fokker–Planck equation along with Max Planck
. After his military service during World War I
he returned to Leiden as Lorentz' and Ehrenfest
's assistant.
In 1928 Fokker succeeded Hendrik Lorentz
as director of research at Teylers Museum
in Haarlem
.
Fokker made several contributions to special relativity
, and some less well-known contributions to general relativity
, particularly in the area of geodetic precession, the phenomena of precession of a freely falling gyroscope in a gravitational field.
Fokker began to study music theory
during the Second World War
, when the University of Leiden was closed; partly this was due to a desire to convince the Nazis
he would be of no use to the war effort, and partly it was a response to reading the work of Christiaan Huygens on the 31 equal temperament
. The year 1942 consequently marked a turning point in his life; after then he wrote many pieces in 31-equal, which are notable for using the 7th harmonic
as a consonant interval (31-equal has a much better approximation of the 7th harmonic than the ubiquitous 12-equal). He also made notable contributions to music theory, such as the Fokker periodicity block.
He died at Beekbergen
(near Apeldoorn
).
. The best-known of these is his 31-tone equal-tempered organ, which was installed in Teyler's Museum in Haarlem in 1951. It is commonly called the Fokker organ.
Netherlands
The Netherlands is a constituent country of the Kingdom of the Netherlands, located mainly in North-West Europe and with several islands in the Caribbean. Mainland Netherlands borders the North Sea to the north and west, Belgium to the south, and Germany to the east, and shares maritime borders...
physicist
Physicist
A physicist is a scientist who studies or practices physics. Physicists study a wide range of physical phenomena in many branches of physics spanning all length scales: from sub-atomic particles of which all ordinary matter is made to the behavior of the material Universe as a whole...
and musician
Musician
A musician is an artist who plays a musical instrument. It may or may not be the person's profession. Musicians can be classified by their roles in performing music and writing music.Also....* A person who makes music a profession....
.
Fokker was born in Buitenzorg, Dutch East Indies
Dutch East Indies
The Dutch East Indies was a Dutch colony that became modern Indonesia following World War II. It was formed from the nationalised colonies of the Dutch East India Company, which came under the administration of the Netherlands government in 1800....
(now Bogor
Bogor
Bogor is a city on the island of Java in the West Java province of Indonesia. The city is located in the center of the Bogor Regency , 60 kilometers south of the Indonesian capital Jakarta...
, Indonesia
Indonesia
Indonesia , officially the Republic of Indonesia , is a country in Southeast Asia and Oceania. Indonesia is an archipelago comprising approximately 13,000 islands. It has 33 provinces with over 238 million people, and is the world's fourth most populous country. Indonesia is a republic, with an...
); he was a cousin of the aeronautical
Aeronautics
Aeronautics is the science involved with the study, design, and manufacturing of airflight-capable machines, or the techniques of operating aircraft and rocketry within the atmosphere...
engineer
Engineer
An engineer is a professional practitioner of engineering, concerned with applying scientific knowledge, mathematics and ingenuity to develop solutions for technical problems. Engineers design materials, structures, machines and systems while considering the limitations imposed by practicality,...
Anthony Fokker
Anthony Fokker
Anton Herman Gerard "Anthony" Fokker was a Dutch aviation pioneer and an aircraft manufacturer. He is most famous for the fighter aircraft he produced in Germany during the First World War such as the Eindecker monoplanes, the Fokker Triplane the and the Fokker D.VII, but after the collapse of...
. He studied mining engineering
Mining engineering
Mining engineering is an engineering discipline that involves the practice, the theory, the science, the technology, and application of extracting and processing minerals from a naturally occurring environment. Mining engineering also includes processing minerals for additional value.Mineral...
at the Delft University of Technology
Delft University of Technology
Delft University of Technology , also known as TU Delft, is the largest and oldest Dutch public technical university, located in Delft, Netherlands...
and physics
Physics
Physics is a natural science that involves the study of matter and its motion through spacetime, along with related concepts such as energy and force. More broadly, it is the general analysis of nature, conducted in order to understand how the universe behaves.Physics is one of the oldest academic...
at the University of Leiden
Leiden University
Leiden University , located in the city of Leiden, is the oldest university in the Netherlands. The university was founded in 1575 by William, Prince of Orange, leader of the Dutch Revolt in the Eighty Years' War. The royal Dutch House of Orange-Nassau and Leiden University still have a close...
with Hendrik Lorentz
Hendrik Lorentz
Hendrik Antoon Lorentz was a Dutch physicist who shared the 1902 Nobel Prize in Physics with Pieter Zeeman for the discovery and theoretical explanation of the Zeeman effect...
, where he earned his doctorate
Doctorate
A doctorate is an academic degree or professional degree that in most countries refers to a class of degrees which qualify the holder to teach in a specific field, A doctorate is an academic degree or professional degree that in most countries refers to a class of degrees which qualify the holder...
in 1913. He continued his studies with Albert Einstein
Albert Einstein
Albert Einstein was a German-born theoretical physicist who developed the theory of general relativity, effecting a revolution in physics. For this achievement, Einstein is often regarded as the father of modern physics and one of the most prolific intellects in human history...
, Ernest Rutherford
Ernest Rutherford
Ernest Rutherford, 1st Baron Rutherford of Nelson OM, FRS was a New Zealand-born British chemist and physicist who became known as the father of nuclear physics...
and William Bragg
William Henry Bragg
Sir William Henry Bragg OM, KBE, PRS was a British physicist, chemist, mathematician and active sportsman who uniquely shared a Nobel Prize with his son William Lawrence Bragg - the 1915 Nobel Prize in Physics...
. In his 1913 thesis, he derived the Fokker–Planck equation along with Max Planck
Max Planck
Max Karl Ernst Ludwig Planck, ForMemRS, was a German physicist who actualized the quantum physics, initiating a revolution in natural science and philosophy. He is regarded as the founder of the quantum theory, for which he received the Nobel Prize in Physics in 1918.-Life and career:Planck came...
. After his military service during World War I
World War I
World War I , which was predominantly called the World War or the Great War from its occurrence until 1939, and the First World War or World War I thereafter, was a major war centred in Europe that began on 28 July 1914 and lasted until 11 November 1918...
he returned to Leiden as Lorentz' and Ehrenfest
Paul Ehrenfest
Paul Ehrenfest was an Austrian and Dutch physicist, who made major contributions to the field of statistical mechanics and its relations with quantum mechanics, including the theory of phase transition and the Ehrenfest theorem.- Biography :Paul Ehrenfest was born and grew up in Vienna in a Jewish...
's assistant.
In 1928 Fokker succeeded Hendrik Lorentz
Hendrik Lorentz
Hendrik Antoon Lorentz was a Dutch physicist who shared the 1902 Nobel Prize in Physics with Pieter Zeeman for the discovery and theoretical explanation of the Zeeman effect...
as director of research at Teylers Museum
Teylers Museum
Teyler's Museum , located in Haarlem, is the oldest museum in the Netherlands. The museum is in the former home of Pieter Teyler van der Hulst . He was a wealthy cloth merchant and Amsterdam banker of Scottish descent, who bequeathed his fortune for the advancement of religion, art and science...
in Haarlem
Haarlem
Haarlem is a municipality and a city in the Netherlands. It is the capital of the province of North Holland, the northern half of Holland, which at one time was the most powerful of the seven provinces of the Dutch Republic...
.
Fokker made several contributions to special relativity
Special relativity
Special relativity is the physical theory of measurement in an inertial frame of reference proposed in 1905 by Albert Einstein in the paper "On the Electrodynamics of Moving Bodies".It generalizes Galileo's...
, and some less well-known contributions to general relativity
General relativity
General relativity or the general theory of relativity is the geometric theory of gravitation published by Albert Einstein in 1916. It is the current description of gravitation in modern physics...
, particularly in the area of geodetic precession, the phenomena of precession of a freely falling gyroscope in a gravitational field.
Fokker began to study music theory
Music theory
Music theory is the study of how music works. It examines the language and notation of music. It seeks to identify patterns and structures in composers' techniques across or within genres, styles, or historical periods...
during the Second World War
World War II
World War II, or the Second World War , was a global conflict lasting from 1939 to 1945, involving most of the world's nations—including all of the great powers—eventually forming two opposing military alliances: the Allies and the Axis...
, when the University of Leiden was closed; partly this was due to a desire to convince the Nazis
Nazism
Nazism, the common short form name of National Socialism was the ideology and practice of the Nazi Party and of Nazi Germany...
he would be of no use to the war effort, and partly it was a response to reading the work of Christiaan Huygens on the 31 equal temperament
31 equal temperament
In music, 31 equal temperament, 31-ET, which can also be abbreviated 31-TET, 31-EDO , , is the tempered scale derived by dividing the octave into 31 equal-sized steps...
. The year 1942 consequently marked a turning point in his life; after then he wrote many pieces in 31-equal, which are notable for using the 7th harmonic
Harmonic series (music)
Pitched musical instruments are often based on an approximate harmonic oscillator such as a string or a column of air, which oscillates at numerous frequencies simultaneously. At these resonant frequencies, waves travel in both directions along the string or air column, reinforcing and canceling...
as a consonant interval (31-equal has a much better approximation of the 7th harmonic than the ubiquitous 12-equal). He also made notable contributions to music theory, such as the Fokker periodicity block.
He died at Beekbergen
Beekbergen
Beekbergen is a village in the Dutch province of Gelderland. It is located in the municipality of Apeldoorn, about 5 km south of that city.Beekbergen was a separate municipality until 1818, when it became a part of Apeldoorn....
(near Apeldoorn
Apeldoorn
Apeldoorn is a municipality and city in the province of Gelderland, about 60 miles south east of Amsterdam, in the centre of the Netherlands. It is a regional centre and has 155,000 . The municipality of Apeldoorn, including villages like Beekbergen, Loenen and Hoenderloo, has over 155,000...
).
Musical instruments
Fokker designed and had built a number of keyboard instruments capable of playing microtonal scales via a generalized keyboardGeneralized keyboard
Generalized keyboards are musical keyboards with regular, tile-like arrangements usually with rectangular or hexagonal keys, and were developed for performing music in different tunings...
. The best-known of these is his 31-tone equal-tempered organ, which was installed in Teyler's Museum in Haarlem in 1951. It is commonly called the Fokker organ.
External links
- Short biography from the Huygens–Fokker Foundation
- Fokker's Euler organ at the Teylers Museum
- H.A.M. Snelders, "Fokker, Adriaan Daniël (1887–1972)", in Biografisch Woordenboek van Nederland. [13-03-2008]
- Oral History interview transcript with Adriaan Fokker, 1 April 1963, American Institute of Physics, Niels Bohr Library and Archives