edited bv MIRIAM C
profile/ in chemi/try Niels Bohr Dennls R. Sievers Central Community High School Breese, IL 62230
Niels Henrik David Bohr was born in Copenhagen, Denmark, on October 7, 1885. His father, Christian Bohr, was a professor of physiology at the University of Copenhagen. His mother, Ellen Adler, was from a prominent Jewish banking family. As a student, Niels was not as brilliant as his brother Harald, who was to become a prominent mathematician. The brothers played on the university soccer team, and Harald, who was more gifted in sports, also made the 1908 silver medal Olvmoic soccer team for Denmark. kolir attended the University of Copenhagen where, in 1906, his first research project on precision measurement of the surface tension of water won him a gold medal from the Academy of Sciences. He received his I'hl) in 1911. His dissertation, "Studier over Metallerness Elektrontheori." still stands as a ~Iassicin the field of electron theory of metals. IJpon ~onclusionof his studies at Copenhagen, Bohr went m the Cavendish laboratories in Cambridge, England, hoping to ulork with J. J. T h o m ~ s o non electron theory. Unforlunately, Thompson had loit interest in the subjeA and failed t o notice the imoact of the younn Dane's dissertation. A second disappointment cameahile a t Cambridge with the reiection of his dissertation for publication by the Cambridge Philosophical Society. Nonetheless, Bohr made the most of his stay in England. H e moved to Manchester in 1912 to work with Ernst Rutherford. These two men, of opposing temperament, were to lay the foundation for the theiry o f atomic constitution. The planetary model of the atom was a revolutionary idea which met with considerable criticism. Working a t a feverish pace, Bohr provided proof of his theory and in the process laid the ground work for quantum mechanics. Amidst all of his work, Niels still had time for a social life. In 1911, he became engaged to Margrethe NBrlund and married her in Copenhagen on August l , 1912, shortly after returnine from Manchester. The union was a most happy and harmohous one, even though Bohr was as intense about his work as ever. The Bohrs had six sons, two of which died while quite young. Niels took his role of father most seriously and devoted much time to his family. In the fall of 1912,Bohr accepted a position a t the University of Copenhagen and began to write of his Manchester ideas. During 1913, his interests changed to atomic radiation. He incorporated ideas of quantum action into the theory of atomic constitution and spent the entire year reconstructing the theory on a new foundation. A large three-part paper was immediately published in the Philosophical Magazine. From 1920 to the early 1930's, Bohr headed an institute for atomic studies sunnorted hv the Carlshera Brewerv-the greatest contribution of beer theoretical since Joule. Much of the research carried out a t the institute was to more fully develop the ideas of quantum theory of atomic radiation and atomic systems. Bohr provided the leadership and direction to inspire younger men like Heisenberg and Pauli. Bohr received the Nobel Prize in 1922 for his work on atomic structure. Political upheaval came to Europe in 1933 with the rise of Hitler. Bohr took what action he could to protest Hitler's ty~
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rannv and to see to the safetv of fellow Jewish scientists. Bohr left Copenhagen in 1939 to"visit the United States. At a scientific meeting in the United States, Bohr brought news that Lise Meitner was about to announce Otto Hahn's concept that uranium atoms a u l d he split by neutron bombardment. With that announcement, the conference disbanded as scientists rushed to their laboratories to test the new suaaestion. Shortly -after this, Bohr returned to Copenhagen. Bohr was still in Copenhagen in 1940 when Hitler's army occupied the nation. T o avoid imprisonment for failure to cooperate, Bohr fled Denmark in 1943 a t the urging of one of his students. His escape to Sweden was a perilous one. While in Sweden. he arraneed for the escaoe of a areat number of Danish ~ e b from s ~ k e r ' gas s ovens: I t was at this time that Niels decided to dissolve in a bottle of acid the Nobel medals of James Frank and MaxVon Laue, which had been given to him for safekeeping. His own medal had been previously given to the Finnish war relief effort. From Sweden, Bohr was flown to Eneland in a tinv plane where he nearly died as a result of n t o the united States where he lack o? oxygen. ~ e t h e went worked at Los Alamos on the atomic bomb project. At the end oft he war, Bohr returned to Copenhagen and recast the Nobel mcdds, a gesture meant to symtr~lizethe passage of the terrom of Nazism and the dawn of the uncertain atomic age. In addition to his hummimian efforLq, he still found energy ro devote to sciencc. Durine the 1920's he onwored the idea of complimentarity. This concept proposed that a phenomenon can he viewed in each of two mutuallv exclusive wavs with --.-both outlooks remaining valid in their own terms. his provided a blend of the Bohr conceot of the electron as a particle and the Schrodinger idea of the electron as a wave. Uoon his return to Cooenhagen, he found conditions drasiically changed. No longer was there the intimacy with other researchers; now secrecy abounded. Bohr did not fare well politically at this time. He expressed great concern over nuclear weapons and urged Western leaders to make contact with the Russians and estahliih b~eacefulrelations and mutual confidence l~rtweenEast and West. He also felt that if every nation had nuclear terhnolrngy, i t would he easier to make them aware of the consequences of nuclear war and to control such awesome wwpons. He attempted to present these views to U.S. I'residmt Franklin Ruoie\,elt and nritish Prime Minipr~r Winston .-.~ .-...~-~~~~ Churchill. hut Churchill iisaid to have heen so angered a t Bohr that he ordered Bohr's arrest should he enter England. In 1950 Bohr decided to approach the United Nations for an onen world as a nrecondition for oeace. His request came a t t i e worst possibie time and fell i n deaf ears. Despite his unsuccessful excursion into the realm of world politics, he devoted much time and energy to his scientific endeavors. He had taken a leading role in the development of a Danish organization for the constructive uses of nuclear power. The first Atoms for Peace Conference was organized by Bohr in 1955. In 1957 he received the Atoms for peace Award for his efforts in peacetime uses of nuclear energy. Niels Bohr, by his persistence, thoroughness, and deep -
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''Fmfiles in Chemisny" is a biographical feature, highlighting the contributims 01 distinguished chemists in Me context of their lives. The column is designed for curriculum enrichment, allowing the secondary schwl teacher to enhance the vitality of chemistry with the sense of scholarship and adventure shared by chemists throughout history.
Volume 59 Number 4
April 1982
303
concern for humankind, represented a scientist's scientist. Bohr died on November 18,1962, in Copenhagen, Denmark, of an apparent stroke. During his lifetime, he proposed a new model for the atom, laid the foundation for quantum mechanics, proposed the idea of complimentarity, worked on the development of nuclear weapons, and showed concern for other human beings who had lost their civil freedoms and for all persons who were to live under the threat of nuclear war.
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Journal of Chemical Education
General References Mmre. Ruth, "Neils Bohr: The Man, His Science, and the World They Changed? Knapf. New York, 1966. of ~ o s c ~ f e l~de. o n , " ~ o~i o~ hs r , "in ~illespie,C. c ~ ~ d i f o r ) , " ~ i c t i o n s r ySciemifie~iqgraphy, Vol. 11: Charles Scribners' Sons, New York. 1970. Raenthal. Stefan,"NoilsBoh.: H'm Lifeand Work AsSeen by His Friends and Cnllespuen," Halrted Press, New York, 1969. s ta the Dismvery of Nuclear Fission? J. CHEMEDUC, starke. ~ u r t ,he ~ e t a u r Leading 56.771 11979).
