Niels Henrik David Bohr

Niels Henrik David Bohr

date of birth : 07/10/1885 | date of death : 18/11/1962
Born on 7 October 1885, Denmark, Philosopher, Footballer

Birth, Birthplace, Time of birth:

Niels Bohr was born in Copenhagen, Denmark, on 7 October 1885.

Father’s name: Christian Bohr
Mother’s name: Ellen Adler Bohr
Brother: Harald August Bohr
Sister: Jennifer Bohr
Spouse: Margrethe Nørlund (m. 1912–1962)
Children: Aage Bohr, Ernest Bohr, Hans Henrik Bohr, Erik Bohr

Reputation, fame, nickname:

Niels Bohr

Personal Information:

Religion: Lutheran

Life events:

The Danish physicist Niels Henrik David Bohr (1885-1962) formulated the first successful explanation of some major lines of the hydrogen spectrum. The Bohr Theory of the atom has become the foundation of modern atomic physics. He was born in Copenhagen on October 7, 1885, as the son of Christian Bohr, Professor of Physiology at Copenhagen University, and his wife Ellen, née Adler. Niels, together with his younger brother Harald (the future Professor in Mathematics), grew up in an atmosphere most favorable to the development of his genius - his father was an eminent physiologist and was largely responsible for awakening his interest in physics while still at school, his mother came from a family distinguished in the field of education. After matriculation at the Gammelholm Grammar School in 1903, he entered Copenhagen University where he came under the guidance of Professor C. Christiansen, a profoundly original and highly endowed physicist, and took his Master's degree in Physics in 1909 and his Doctor's degree in 1911. While still a student, the announcement by the Academy of Sciences in Copenhagen of a prize to be awarded for the solution of a certain scientific problem caused him to take up an experimental and theoretical investigation of the surface tension by means of oscillating fluid jets. This work, which he carried out in his father's laboratory and for which he received the prize offered (a gold medal), was published in the Transactions of the Royal Society, 1908. Bohr's subsequent studies, however, became more and more theoretical in character, his doctor's disputation being a purely theoretical piece of work on the explanation of the properties of the metals with the aid of the electron theory, which remains to this day a classic on the subject. It was in this work that Bohr was first confronted with the implications of Planck's quantum theory of radiation. In the autumn of 1911 he made a stay at Cambridge, where he profited by following the experimental work going on in the Cavendish Laboratory under Sir J.J. Thomson's guidance, at the same time as he pursued own theoretical studies. In the spring of 1912 he was at work in Professor Rutherford's laboratory in Manchester, where just in those years such an intensive scientific life and activity prevailed as a consequence of that investigator's fundamental inquiries into the radioactive phenomena. Having there carried out a theoretical piece of work on the absorption of alpha rays which was published in the Philosophical Magazine, 1913, he passed on to a study of the structure of atoms on the basis of Rutherford's discovery of the atomic nucleus. By introducing conceptions borrowed from the Quantum Theory as established by Planck, which had gradually come to occupy a prominent position in the science of theoretical physics, he succeeded in working out and presenting a picture of atomic structure that, with later improvements (mainly as a result of Heisenberg's ideas in 1925), still fitly serves as an elucidation of the physical and chemical properties of the elements. In 1913-1914 Bohr held a Lectureship in Physics at Copenhagen University and in 1914-1916 a similar appointment at the Victoria University in Manchester. In 1916 he was appointed Professor of Theoretical Physics at Copenhagen University, and since 1920 (until his death in 1962) he was at the head of the Institute for Theoretical Physics, established for him at that university. Recognition of his work on the structure of atoms came with the award of the Nobel Prize for 1922. Bohr's activities in his Institute were since 1930 more and more directed to research on the constitution of the atomic nuclei, and of their transmutations and disintegrations. In 1936 he pointed out that in nuclear processes the smallness of the region in which interactions take place, as well as the strength of these interactions, justify the transition processes to be described more in a classical way than in the case of atoms (Cf. »Neutron capture and nuclear constitution«, Nature, 137 (1936) 344). A liquid drop would, according to this view, give a very good picture of the nucleus. This so-called liquid droplet theory permitted the understanding of the mechanism of nuclear fission, when the splitting of uranium was discovered by Hahn and Stresemann, in 1939, and formed the basis of important theoretical studies in this field (among others, by Frisch and Meitner). Bohr also contributed to the clarification of the problems encountered in quantum physics, in particular by developing the concept of complementarity. Hereby he could show how deeply the changes in the field of physics have affected fundamental features of our scientific outlook and how the consequences of this change of attitude reach far beyond the scope of atomic physics and touch upon all domains of human knowledge. These views are discussed in a number of essays, written during the years 1933-1962. They are available in English, collected in two volumes with the title Atomic Physics and Human Knowledge and Essays 1958-1962 on Atomic Physics and Human Knowledge, edited by John Wiley and Sons, New York and London, in 1958 and 1963, respectively. Among Professor Bohr's numerous writings (some 115 publications), three appearing as books in the English language may be mentioned here as embodying his principal thoughts: The Theory of Spectra and Atomic Constitution, University Press, Cambridge, 1922/2nd. ed., 1924; Atomic Theory and the Description of Nature, University Press, Cambridge, 1934/reprint 1961; The Unity of Knowledge, Doubleday & Co., New York, 1955. During the Nazi occupation of Denmark in World War II, Bohr escaped to Sweden and spent the last two years of the war in England and America, where he became associated with the Atomic Energy Project. In his later years, he devoted his work to the peaceful application of atomic physics and to political problems arising from the development of atomic weapons. In particular, he advocated a development towards full openness between nations. His views are especially set forth in his Open Letter to the United Nations, June 9, 1950. Until the end, Bohr's mind remained alert as ever; during the last few years of his life he had shown keen interest in the new developments of molecular biology. The latest formulation of his thoughts on the problem of Life appeared in his final (unfinished) article, published after his death: "Licht und Leben-noch einmal", Naturwiss., 50 (1963) 72: (in English: "Light and Life revisited", ICSU Rev., 5 ( 1963) 194). Niels Bohr was President of the Royal Danish Academy of Sciences, of the Danish Cancer Committee, and Chairman of the Danish Atomic Energy Commission. He was a Foreign Member of the Royal Society (London), the Royal Institution, and Academies in Amsterdam, Berlin, Bologna, Boston, Göttingen, Helsingfors, Budapest, München, Oslo, Paris, Rome, Stockholm, Uppsala, Vienna, Washington, Harlem, Moscow, Trondhjem, Halle, Dublin, Liege, and Cracow. He was Doctor, honoris causa, of the following universities, colleges, and institutes: (1923-1939) - Cambridge, Liverpool, Manchester, Oxford, Copenhagen, Edinburgh, Kiel, Providence, California, Oslo, Birmingham, London; (1945-1962) - Sorbonne (Paris), Princeton, Mc. Gill (Montreal), Glasgow, Aberdeen, Athens, Lund, New York, Basel, Aarhus, Macalester (St. Paul), Minnesota, Roosevelt (Chicago, Ill.), Zagreb, Technion (Haifa), Bombay, Calcutta, Warsaw, Brussels, Harvard, Cambridge (Mass.), and Rockefeller (New York). Professor Bohr was married, in 1912, to Margrethe Nørlund, who was for him an ideal companion. They had six sons, of whom they lost two; the other four have made distinguished careers in various professions - Hans Henrik (M.D.), Erik (chemical engineer), Aage (Ph.D., theoretical physicist, following his father as Director of the Institute for Theoretical Physics), Ernest (lawyer).


High School: Gammelholm Grammar School, Copenhagen (1903)
University: MA Physics, University of Copenhagen (1909)
University: PhD Physics, University of Copenhagen (1911)

Occupation and Career:

Niels Henrik David Bohr was a Danish physicist, philosopher and footballer, who made foundational contributions to understanding atomic structure and quantum mechanics, for which he received the Nobel Prize in Physics in 1922. One of his sons, Aage Bohr, was also a physicist and in 1975 also received the Nobel Prize. Bohr was a passionate footballer who played goalkeeper for the Copenhagen-based Akademisk Boldklub, but was not as accomplished a player as his brother Harald Bohr, who played for the Danish national team at the 1908 Summer Olympics. Bohr developed the Bohr model of the atom with the atomic nucleus at the centre and electrons in orbit around it, which he compared to the planets orbiting the Sun. He worked on the idea in quantum mechanics that electrons move from one energy level to another in discrete steps, not continuously. He founded the Institute of Theoretical Physics at the University of Copenhagen, now known as the Niels Bohr Institute, which opened in 1920. Bohr mentored and collaborated with physicists including Hans Kramers, Oskar Klein, George de Hevesy and Werner Heisenberg. He predicted the existence of a new zirconium-like element, which was named hafnium, after Copenhagen, when it was discovered. Later, the element Bohrium was named after him. He conceived the principle of complementarity: that items could be separately analysed as having contradictory properties, like behaving as a wave or a stream of particles. The notion of complementarity dominated his thinking on both science and philosophy. During the 1930s, Bohr gave refugees from Nazism temporary jobs at the Institute, provided them with financial support, arranged for them to be awarded fellowships from the Rockefeller Foundation, and ultimately found them places at various institutions around the world. After Denmark was occupied by the Germans, he had a dramatic meeting with Heisenberg, the head of the German nuclear energy project in Copenhagen. In 1943, fearing arrest, Bohr fled to Sweden, where he persuaded King Gustav V of Sweden to make public Sweden's willingness to provide asylum. He was then flown to Britain, where he joined the British Tube Alloys nuclear weapons project, and was part of the British team of physicists who worked on the Manhattan Project. After the war, Bohr called for international cooperation on nuclear energy. He was involved with the establishment of CERN, and became the first chairman of the Nordic Institute for Theoretical Physics in 1957. He was also involved with the founding of the Risø DTU National Laboratory for Sustainable Energy.

Awards /Honors:

  • Nobel Prize in Physics (1922)
  • Franklin Medal (1926)
  • Order of the Elephant (1947)
  • Atoms for Peace Award (1957)


  • The Philosophical Writings of Niels Bohr (1987, essays; three volumes)
  • Niels Bohr: Collected Works (2008, thirteen volumes)

Hobbies and personal interests:

One of Niels's hobbies was rode motorcycles and modeling. Go to Tivoli with family and friends.

Death, place of death, Time of death, place of burial:

He died at his home in Carlsberg on 18 November 1962 of heart failure. He was cremated and his ashes buried in the family plot Assistens Kirkegård in the Nørrebro section of Copenhagen, along with those of his parents, his brother Harald, and son Christian. Years later, his wife's ashes would also be interred there.

Quotes and Memoirs:

  • Everything we call real is made of things that cannot be regarded as real.
  • Prediction is very difficult, especially if it's about the future.
  • An expert is a man who has made all the mistakes which can be made, in a narrow field.
  • Every great and deep difficulty bears in itself its own solution. It forces us to change our thinking in order to find it.
  • If quantum mechanics hasn't profoundly shocked you, you haven't understood it yet.
  • Your theory is crazy, but it's not crazy enough to be true.
  • Never express yourself more clearly than you are able to think.
  • There are some things so serious you have to laugh at them.
  • How wonderful that we have met with a paradox. Now we have some hope of making progress.