Johann Jakob Balmer (1 May 1825 – 12 March 1898) was a
Swiss mathematician
A mathematician is someone who uses an extensive knowledge of mathematics in their work, typically to solve mathematical problems.
Mathematicians are concerned with numbers, data, quantity, structure, space, models, and change.
History
On ...
best known for his work in
physics
Physics is the natural science that studies matter, its fundamental constituents, its motion and behavior through space and time, and the related entities of energy and force. "Physical science is that department of knowledge which r ...
, the
Balmer series
The Balmer series, or Balmer lines in atomic physics, is one of a set of six named series describing the spectral line emissions of the hydrogen atom. The Balmer series is calculated using the Balmer formula, an empirical equation discovered b ...
of
hydrogen
Hydrogen is the chemical element with the symbol H and atomic number 1. Hydrogen is the lightest element. At standard conditions hydrogen is a gas of diatomic molecules having the formula . It is colorless, odorless, tasteless, non-toxic ...
atom.
Biography
Balmer was born in
Lausen
Lausen is a municipality in the district of Liestal in the canton of Basel-Country in Switzerland.
History
Lausen is first mentioned in 1275 as ''in villa et banno Langenso''. In 1305 it became the property of the Bishop of Basel, passing in ...
,
Switzerland, the son of a chief justice also named Johann Jakob Balmer. His mother was Elizabeth Rolle Balmer, and he was the oldest son. During his schooling he excelled in mathematics, and so decided to focus on that field when he attended university.
He studied at the
University of Karlsruhe
The Karlsruhe Institute of Technology (KIT; german: Karlsruher Institut für Technologie) is a public research university in Karlsruhe, Germany. The institute is a national research center of the Helmholtz Association.
KIT was created in 2009 w ...
and the
University of Berlin
Humboldt-Universität zu Berlin (german: Humboldt-Universität zu Berlin, abbreviated HU Berlin) is a German public research university in the central borough of Mitte in Berlin. It was established by Frederick William III on the initiative ...
, then completed his
PhD from the
University of Basel
The University of Basel (Latin: ''Universitas Basiliensis'', German: ''Universität Basel'') is a university in Basel, Switzerland. Founded on 4 April 1460, it is Switzerland's oldest university and among the world's oldest surviving universit ...
in 1849 with a
dissertation on the
cycloid
In geometry, a cycloid is the curve traced by a point on a circle as it rolls along a straight line without slipping. A cycloid is a specific form of trochoid and is an example of a roulette, a curve generated by a curve rolling on another cu ...
. Johann then spent his entire life in Basel, where he taught at a school for girls. He also lectured at the
University of Basel
The University of Basel (Latin: ''Universitas Basiliensis'', German: ''Universität Basel'') is a university in Basel, Switzerland. Founded on 4 April 1460, it is Switzerland's oldest university and among the world's oldest surviving universit ...
. In 1868 he married Christine Pauline Rinck at the age of 43. The couple had six children.
Despite being a mathematician, Balmer is best remembered for his work on spectral series. His major contribution (made at the age of sixty, in 1885) was an
empirical formula for the visible
spectral line
A spectral line is a dark or bright line in an otherwise uniform and continuous spectrum, resulting from emission or absorption of light in a narrow frequency range, compared with the nearby frequencies. Spectral lines are often used to iden ...
s of the
hydrogen
Hydrogen is the chemical element with the symbol H and atomic number 1. Hydrogen is the lightest element. At standard conditions hydrogen is a gas of diatomic molecules having the formula . It is colorless, odorless, tasteless, non-toxic ...
atom, the study of which he took up at the suggestion of
Eduard Hagenbach also of Basel. Using
Ångström
The angstromEntry "angstrom" in the Oxford online dictionary. Retrieved on 2019-03-02 from https://en.oxforddictionaries.com/definition/angstrom.Entry "angstrom" in the Merriam-Webster online dictionary. Retrieved on 2019-03-02 from https://www.m ...
's measurements of the hydrogen lines, he arrived at a
formula for computing the wavelength as follows:
:
for ''n'' = 2 and ''m'' = 3, 4, 5, 6, and so forth; ''h'' = 3.6456×10
−7 m.
In his 1885 notice, he referred to ''h'' (now known as the ''Balmer constant'') as the "fundamental number of hydrogen." Balmer then used this formula to predict the wavelength for ''m'' = 7 and Hagenbach informed him that Ångström had observed a line with wavelength 397
nm. This portion of the Hydrogen emission spectrum, from energy levels n<2 to n=2, became known as the
series
Series may refer to:
People with the name
* Caroline Series (born 1951), English mathematician, daughter of George Series
* George Series (1920–1995), English physicist
Arts, entertainment, and media
Music
* Series, the ordered sets used in ...
. The Balmer lines refer to the four emission spectrum lines that occur within the visible region of the Hydrogen emission spectrum at 410 nm, 434 nm, 486 nm, and 656 nm. These lines are caused by electrons in an
excited state returning to
ground state energy levels. Two of his colleagues,
Hermann Wilhelm Vogel
Hermann Wilhelm Vogel (26 March 1834 – 17 December 1898) was a German photochemist and photographer who discovered dye sensitization, which is of great importance to photography.
Academic career
After finishing school in Frankfurt (Oder), ...
and
William Huggins
Sir William Huggins (7 February 1824 – 12 May 1910) was an English astronomer best known for his pioneering work in astronomical spectroscopy together with his wife, Margaret.
Biography
William Huggins was born at Cornhill, Middlesex, in ...
, were able to confirm the existence of other lines of the Balmer series in the spectrum of hydrogen in white stars.
Balmer's formula was later found to be a special case of the
Rydberg formula
In atomic physics, the Rydberg formula calculates the wavelengths of a spectral line in many chemical elements. The formula was primarily presented as a generalization of the Balmer series for all atomic electron transitions of hydrogen. It wa ...
, devised by
Johannes Rydberg
Johannes (Janne) Robert Rydberg (; 8 November 1854 – 28 December 1919) was a Swedish physicist mainly known for devising the Rydberg formula, in 1888, which is used to describe the wavelengths of photons (of visible light and other electrom ...
in 1888.
:
with
being the
Rydberg constant for hydrogen,
for Balmer's formula, and
.
A full explanation of why these formulas worked, however, had to wait until the presentation of the
Bohr model of the atom
In atomic physics, the Bohr model or Rutherford–Bohr model, presented by Niels Bohr and Ernest Rutherford in 1913, is a system consisting of a small, dense nucleus surrounded by orbiting electrons—similar to the structure of the Solar Sy ...
by
Niels Bohr
Niels Henrik David Bohr (; 7 October 1885 – 18 November 1962) was a Danish physicist who made foundational contributions to understanding atomic structure and quantum theory, for which he received the Nobel Prize in Physics in 1922 ...
in 1913.
Johann Balmer died in Basel, aged 72.
Honors
*Balmer formula and Balmer constant ''h'' are named after him, as well as
Balmer line
The Balmer series, or Balmer lines in atomic physics, is one of a set of six named series describing the spectral line emissions of the hydrogen atom. The Balmer series is calculated using the Balmer formula, an empirical equation discovered b ...
s and
Balmer series
The Balmer series, or Balmer lines in atomic physics, is one of a set of six named series describing the spectral line emissions of the hydrogen atom. The Balmer series is calculated using the Balmer formula, an empirical equation discovered b ...
.
*The
Balmer jump
The Balmer jump, Balmer discontinuity, or Balmer break is the difference of intensity of the stellar continuum spectrum on either side of the limit of the Balmer series of hydrogen, at approximately 364.5 nm. It is caused by electrons being co ...
is useful in
Astronomy
Astronomy () is a natural science that studies celestial objects and phenomena. It uses mathematics, physics, and chemistry in order to explain their origin and evolution. Objects of interest include planets, moons, stars, nebulae, g ...
for
stellar classification.
*The crater
Balmer on the
Moon
The Moon is Earth's only natural satellite. It is the fifth largest satellite in the Solar System and the largest and most massive relative to its parent planet, with a diameter about one-quarter that of Earth (comparable to the width of ...
is named after him.
*
Minor planet
According to the International Astronomical Union (IAU), a minor planet is an astronomical object in direct orbit around the Sun that is exclusively classified as neither a planet nor a comet. Before 2006, the IAU officially used the term ''mino ...
12755 Balmer is named after him.
References
External links
*
{{DEFAULTSORT:Balmer, Johann
1825 births
1898 deaths
19th-century Swiss physicists
19th-century Swiss mathematicians
Scientists from Basel-Stadt
Spectroscopists
People from Basel-Landschaft