GUSTAV KIRCHHOFF: BIOGRAPHY, LAWS, CONTRIBUTIONS, WORKS - BIOGRAPHIES - 2025

Gustav Kirchhoff (1824-1887) was a German physicist born in March 1824 in then East Prussia. During his scientific career he made important contributions in fields such as electricity, spectroscopy or the measurement of radiation from black bodies.

From a very young age, Kirchhoff was encouraged by his family to dedicate himself to university teaching. Since in high school he showed his good conditions for mathematics, he decided to opt for that subject, although in the physical-mathematical branch. At Königberg, where he studied, he came into contact with important scientists who influenced his research.

Gustav Kirchhoff - Source: Smithsonian Libraries under Public Domain

Without having finished his university studies yet, Kirchhoff presented some of his first works. Among the most prominent are the two sets of laws that bear his name. One is dedicated to thermal radiation, although the most important was the laws related to electrical engineering.

Kirchhoff spent most of his career at the University of Heidelberg, despite receiving offers from other more renowned centers. Only in his old age and with a rather precarious state of health did he move to Berlin. Despite this, he remained active until the time of his death, in October 1887.

Biography

Gustav Robert Kirchhoff was born in Königberg (then the capital of East Prussia) on October 12, 1824. At that time, the city was known for its intellectual activity, to the point that it was nicknamed the "City of Pure Reason."

His family belonged to the local elite, as his father was a lawyer known for his devotion to the Prussian state.

Gustav's high intellectual abilities began to show themselves from a very young age. In addition, his education was directed by his father made the obligation to serve Prussia.

Both factors caused his professional steps to be focused on becoming a university professor, since at the time these were public officials, which coincided with his father's desire that he put his skills at the service of his country.

Education

The Kneiphof Institute was the place chosen by his family for the young Gustav to attend high school. In that center he began to show his good conditions for mathematics, which led him to orient his university studies towards that subject.

Kirchhoff entered the university center in his hometown, the Albertus University. This institution was known for the seminar on mathematical physics established by Franz Neumann (considered the father of theoretical physics in the country) and by Carl Gustav Jakob Jacobi (one of the most eminent mathematicians of the time).

The future scientist attended this seminar between 1843 and 1846. However, he could not take advantage of the teachings of Jacobi, who was ill, and for this reason it was Neumman who had the greatest influence on his training.

Neumann had begun to be interested in electrical induction by that date and had published his first two works on induction in 1845. This caused Kirchhoff, as a disciple of his, to begin to pay attention to that subject as well. Besides, he also studied mathematics with Friedrich Jules Richelot.

First publications

As early as 1845, when he was still studying, Kirchhoff presented a work on the flow of electricity in a circular plate. This study would later be the basis of his doctoral thesis.

That same year he took as a reference a theory presented by another physicist, Georg Simon Ohm, to formulate what would be known as Kirchhoff's Laws of electrical engineering.

Transfer to Berlin

The first consequence of the publication of the Laws of Kirchhoff was that the author received a scholarship to continue his training in Paris. However, the situation in Europe at the time was very tense, especially between Prussia and France, which would eventually go to war in 1870.

For this reason, Kirchhoff rejected the option of moving to the French capital. Instead, he settled in Berlin, where he began working as a Privatdozent (a professor who did not receive any salary) at the University of that city.

During the time in which he carried out this activity, the scientist did not stop publishing the results of his research. Among these he highlighted his contribution to the theory of electric and electrostatic currents.

His next destination was Breslau (nowadays called Wroclaw), where he was appointed Professor Extraordinary.

Heidelberg University

Kirchhoff's stay in Breslau lasted a year, from 1851 to 1852. During this time, the physicist befriended Robert Bunsen, a well-known chemist.

It was Bunsen who convinced Kirchhoff to leave the city to start working as a physics teacher in Heidelberg. The collaboration between the two friends was very fruitful and both became regulars at the meetings carried out by a group of scientists organized by Hermann von Helmholtz.

Gustav Kirchhoff married in 1857 the daughter of his former mathematics teacher at Konigsberg. However, his wife, Clara Richelot, passed away in 1869, leaving the scientist alone in the care of the five children they had in common. In 1872, the scientist remarried, this time with Luise Brömmel.

At that time, Kirchhoff's health, which had always been precarious, deteriorated and he was forced to use a wheelchair or, failing that, crutches.

The fame of the scientist was increasing and numerous universities sent him offers to join their staff. Kirchhoff, however, preferred to remain in Heidelberg.

Back to Berlin

Kirchhoff's state of health was getting worse and worse. Soon he began to have difficulty conducting the necessary experiments to confirm his investigations. Despite his desire not to leave Heidelberg, in the end he decided to accept an offer from the University of Berlin to occupy the chair of physics-mathematics.

Kirchhoff joined his new post in 1875 and, in addition to teaching duties, continued to conduct theoretical research. The result was one of his best-known treatises: Vorlesungen über mathematischen Physik, published in four volumes when he had already left the Berlin professorship.

At the age of 63, Gustav Kirchhoff died in Berlin on October 17, 1887.

Kirchhoff's Laws

Kirchhoff's Laws are two groups of laws on electrical circuits and thermal emission.

Both sets of laws are named after their author, although the best known are those relating to electrical engineering.

Kirchhoff's three laws of spectroscopy

The scientist developed a set of laws to describe how the emission of light by incandescent objects behaves:

1- A hot solid object produces light in a continuous spectrum.

2- A tenuous gas produces light with spectral lines at discrete wavelengths that depend on the chemical composition of the gas.

3- A solid object at high temperature surrounded by a tenuous gas at lower temperatures produces light in a continuous spectrum with gaps at discrete wavelengths whose positions depend on the chemical composition of the gas.

The three laws on Kirchhoff's spectrography were, later, the basis for the emergence of quantum mechanics.

Kirchhoff's Laws of Electrical Engineering

As noted, the set of laws on electricity formulated by Kirchhoff was his most relevant contribution to science. To do this, he drew on previous work by Georg Simon Ohm.

These laws soon became fundamental tools for circuit analysis. In a very summarized way, its extension allows to measure the intensity of the current, as well as the potential difference at a certain point within an electricity circuit.

- Kirchhoff's First Law or Law corresponding to the nodes: “In any node, the algebraic sum of the electrical currents that enter is equal to the sum of the currents that leave. As an equivalent, the algebraic sum of all the currents that pass through the node is equal to zero "

- Kirchhoff's Second Law or Law corresponding to the meshes: “in a closed circuit of a network, the sum of the set of voltage drops in its components is equal to the sum of the supplied voltages and, therefore, the algebraic sum of the potential differences in a mesh are zero. "

Contributions

Aside from the laws that bear his name, Kirchhoff made many more contributions to science, both practical and theoretical. Thus, he dedicated his efforts to improving knowledge about electricity, plate theory, optics and spectroscopy, among other fields of study.

Likewise, he carried out various investigations on how heat conduction occurs and tried to measure the spectrum of celestial bodies, including the sun and nebulae. The latter helped him create a spatial atlas and demonstrate the relationship between the absorption of light and its emission.

Kirchhoff diffraction formula

Kirchhof used the diffraction theory presented by Fresnel in 1818 to develop a formula that describes how light waves behave when they pass through a small aperture.

The spectrograph and new spectrographic analysis techniques

As noted, the collaboration between Gustav Kirchhoff and Robert Bunsen during their stay at the University of Heidelberg was very fruitful. Both scientists tried pioneering techniques for spectrographic analysis. In practice, this allowed them to discover two new chemical elements: rubidium and cesium.

In order to make these discoveries, the two researchers had to make a new instrument: the modern spectrograph. It projects a flame onto the bottom of a scale of different wavelengths. Thus, they were able to locate the spectral lines, which appear when light breaks down into its spectrum.

Spectral composition of the Sun

Another of Kirchhoff's investigations was to try to measure the spectral composition of our star, the Sun.

This research allowed him to find out that when light passes through any type of gas, it absorbs its wavelengths, just as it would if it were previously heated. This property was christened the Fraunhofer lines.

Kirchhoff used the knowledge gained as an explanation for the dark lines present in the solar spectrum and that intensify when sunlight passes through a flame. The result of this research was the promulgation of the Kirchhoff-Clausius Emission Law and it was the beginning of a new stage in the field of astronomy.

The scientist used the results obtained to determine, in 1861, the presence in the Sun of elements such as magnesium, zinc, sodium or copper, as occurs in the crust of the Earth.

Ultimately, these studies helped him create a map of the solar spectrum. The map, printed in four-color, was commissioned by the Berlin Academy of Sciences.

Elastic plate deformation

The scientist also spent part of his time solving some problems related to elastic plates and their deformation.

The first theory on this subject had been published by Sophie Germain and Siméon Denis Poisson and, later, perfected by Claude-Louis Navier. Kirchhoff's job, who used the differential calculus, was to answer the questions that still remained unsolved.

Works and publications

Gustav Kirchhoff was the author, alone or in collaboration with other colleagues, of several scientific works.

Among the most important are the one devoted to chemical elements and their spectra, Untersuchungen über das Sonnenspektrum und die Spektren chemischer Elementen (1861-1863); his four volumes on mathematical physics, Vorlesungen über mathematischen Physik (1876-1894), and the Gesammelte Abhandlungen.

Awards and honours

Gustav Kirchhoff's contributions to science were recognized by a large number of institutions of his time. Among those who named him a member were the Royal Society, the American Academy of Arts and Sciences, the Russian Academy of Sciences, and the Prussian Academy of Sciences.

In addition, the scientist also received the following awards and prizes in recognition of his work.

- Order of Merit of Sciences and Arts.

- Rumford Medal.

- Bavarian Order of Maximilian for Science and the Arts.

- Matteucci Medal.

- Davy Medal.

After his death he also received the Jansen medal and a lunar crater and an asteroid were baptized with his surname.

References

1. Biographies and Lives. Gustav Kirchhoff. Obtained from biografiasyvidas.com
2. McAllister, Willy. Kirchhoff's laws. Recovered from es.khanacademy.org
3. EcuRed. Gustav Kirchhoff. Obtained from ecured.cu
4. The Editors of Encyclopaedia Britannica. Gustav Kirchhoff. Retrieved from britannica.com
5. Famous Scientists. Gustav Kirchhoff. Retrieved from famousscientists.org
6. New World Encyclopedia. Gustav Kirchhoff. Retrieved from newworldencyclopedia.org
7. Science History Institute. Robert Bunsen and Gustav Kirchhoff. Retrieved from sciencehistory.org
8. Robertson, EF; O'Connor, JJ Gustav Robert Kirchhoff. Retrieved from groups.dcs.st-and.ac.uk