- Johann Jakob Balmer
Infobox Scientist

name = Johann Jakob Balmer

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caption = Johann Jakob Balmer

birth_date =May 1 1825

birth_place =Lausen ,Switzerland

death_date =March 12 1898

death_place =Basel

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nationality =Switzerland

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field =mathematics

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alma_mater =University of Basel

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**Johann Jakob Balmer**(May 1 1825 –March 12 1898 ) was a Swissmathematician and an honoraryphysicist .**Life and work**He was born in

Lausen ,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 and theUniversity of Berlin , then completed hisPh.D. from theUniversity of Basel in 1849 with adissertation on thecycloid . Johann then spent his entire life in Basel, where he taught at a school for girls. He also lectured at the University of Basel. In 1868 he married Christine Pauline Rinck at the age of 43. The couple had a total of six children.Despite being a mathematician, he is not remembered for any work in that field; rather, his major contribution (made at the age of sixty, in 1885) was an

empirical formula for the visiblespectral line s of thehydrogen atom the study of which he took up at the suggestion of Eduard Hagenbach also of Basel [*cite book|last=Magie|first=William Francis|title=A Source Book in Physics|publisher=Harvard University Press|location=Cambridge, Mass|year=1969 p 360*] . Using Ångström's measurements of the hydrogen lines, he arrived at a formula for computing the wavelength as follows::$lambda\; =\; frac\{\; h\; m^2\; \}\{\; m^2\; -\; n^2\; \}$

for "n" = 2, "h" = 3.6456×10

^{−7}m, and "m" = 3, 4, 5, 6, and so forth. In his 1885 notice he referred to "h" 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 4968.1 Å. Two of his colleagues, H. W. Vogel and Huggins, were able to confirm the existence of other lines of the series for the spectrum of hydrogen of white stars.Balmer's formula was later found to be a special case of the

Rydberg formula , devised byJohannes Rydberg .: $frac\{1\}\{lambda\}\; =\; R\_H\; (\; frac\{1\}\{n\_1^2\}\; -\; frac\{1\}\{n\_2^2\}\; )$

with $R\_H$ being the Rydberg constant for hydrogen, $n\_1\; =\; 2$ for Balmer's formula, and $n\_2\; >\; n\_1$.

A full explanation of why these formulas worked, however, had to wait until the presentation of the

Bohr model of the atom byNiels Bohr in 1913.Johann Balmer died in Basel.

**Honors***

Balmer line s andBalmer series are named after him.

*Balmer crater on theMoon is named after him.**References****External links***

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