The Contributions of Niels Bohr

The Contributions of Niels Bohr

Niels Bohr was one of the greatest scientists in the 20th century. He created a model of atomic structure and he established the foundations of quantum mechanics for which he received the Nobel Prize on December 10, 1922. In this following research paper I am going to write about the background of Niels Bohr, analyze his ground-breaking contributions, and look at the developments that followed from Bohr’s work, and how human society benefits from his work.

Niels Henrik David Bohr was born in Copenhagen, the capital city of Demark on October 7, 1885. Bohr was raised in an amicable and inspiring family. His father, Christian Bohr, was a physiology professor in University of Copenhagen, and his mother Ellen Adler Bohr came from an opulent Jewish educator’s family. (Nobel Prize) Christian and Ellen had three children: Jenny, Niels and Harald. According to Margrethe Bohr, Niels Bohr’s wife, she claimed: “[Niels] had such a very happy home life with this combination of a very intelligent and wise father and a very loving mother. His mother, Ellen wasn’t merely loving, she was also very clear in thought… The mother read very much to [the children]. When [Niels] was older he discussed scientific and other topics with his father….” (Pais 43) In Niels’ childhood, his brother Harald Bohr, who became a mathematician in later years, was his real best friend; they both went to the same school for primary and secondary in Gammelholm, Copenhagen. (Pais 48) The brothers gathered together and conversed about science theories, and the young Niels usually asked opinions from Harald to see his perspectives. (Gale) In the autumn of 1903, Niels Bohr entered the University of Copenhagen. Niels chose physics as his major, and he also selected chemistry, philosophy, mathematics as his minors. Bohr’s physics professor was Christian Christiansen, and he was a prominent physicist in Demark. Studying along with his professor, Bohr learned lots from professor Christiansen. Bohr’s first theoretical science paper was about the tension of liquids. Bohr performed all the experiments by himself, but he did not write the paper, due to his poor handwriting, instead he requested someone else to write for him and submitted after the deadline. This paper was also amended and sent it to Danish National Academy, and won a golden medal prize. (Pais 102) In 1909, his brother Harald received a master degree before Neils received his in mathematics. Two years later in 1911, Niels received his doctorate degree in Physics. In 1911, his father pasted away and he also got engaged with Ellen. Later that year, he went to Cambridge, England continued his post-doctoral education. He carried his Ph.D. thesis translation, after he arrived in Cambridge, Bohr worked under Joseph John Thomson, who won the Nobel Prize in 1906 for his discovery of the electron, and also J.J Thomson who was the director of Cavendish, a world leading Physics -experimental center. Bohr also studied the properties of atoms with James Rutherford after he moved to Manchester. Niels developed a model of atomic structure using Rutherford’s description of nucleus and Planck’s quantum theory. In 1920, Bohr moved back to Copenhagen University and became the head of Institute for Theoretical Physics department. This Institute was named after Bohr, and the department became a world leading center of quantum mechanics. In the 1920s, Niels Bohr first met Albert Einstein and debated the quantum theory of light. This was a famous science debate that last for 30 years. Einstein disapproved Bohr’s hypothesis about the light quantum in his theory. During the WWII, Germany conquered Demark. The Nazis tried to capture Bohr as a prisoner, because his mother had Jewish background. Bohr melted his Noble Prize into a silver container and he escaped Denmark to Sweden and took a plane to London. He eventually arrived in United States. In the US, he joined the Manhattan Project, to build a secret weapon, the atomic bombs, in Los Almaos lab, New Mexico. In Bohr’s life, he advocated peaceful ways to use nuclear energy, and suggested to share the nuclear information with the Soviet Union, for which he was criticized by Winston Churchill, Prime Minister in Britain.

There are two significant works that Niels Bohr contributed to the world, atomic model and quantum mechanics theory. Max Planck, a German physicist with his blackbody radiation and Einstein’s light quantum and heat capacities, and Bohr’s atomic structure were the three principles of quantum physics. The three of them were regarded as the founders of quantum mechanics. When Niels did his postdoctoral education in England, he adopted Rutherford’s nucleus structure and Max Planck’s quantum theory, and then he published the atomic structure in 1913. Bohr pointed out in his quantum theory that all atoms were similar to a micro-solar system, electrons were spinning around the heavy nucleus. His hypothesis assumed that the number of electrons in an atom decided an atom’s properties. (Kragh 55) In addition, he also claimed that if a higher level electron from its atom transited to the lower level orbit, the movement would release a photon. (Pais 179) After he published his ideas in Britain, there was a splash happening, a few people supported his idea, but there were many scientists against his theory. (Kragh) From a traditional physics perspective, motion and energy were consistence. Physicists used mathematics to calculate the movements of electrons, but it gained the result. Bohr’s quantum theory was opposite the classical mathematical thinking, and Bohr insisted energy inconsistency, and he used matrix mechanics and Fourier to record and calculate the movement of electrons.

At Copenhagen University, Bohr was the first professor in theoretical physics department. Under Bohr’s great influence, he instructed many talented young students, Werner Heisenburg, one of his students, who won a Nobel Prize in 1932, helped him developed the uncertainty principle and complementarity principle. In later years, Heisenburg based his work on Bohr’s quantum theory and developed matrix formation in 1925. Niels Bohr’s contributions certainly marked a new epoch in society. His works helped people understand atomic structure, created the atomic bomb, nuclear power plants… Without a doubt, Niels Bohr was one of the greatest scientists in the 20th century.

“The Nobel Prize in Physics 1922”. Nobel 10 Jun 2012.
Pais, Abraham. Niels Bohr’s Times, In Physics, Philosophy, and Polity. New York: Oxford University Press, 1991. Print.
Gale, Thomson. World of Mathematics. Thomson Corporation. 2005. Web.
Kragh, Helge. The Theory of the Periodic System. Harvard University, 1985.
Kragh, Helge. “Resisting the Bohr Atom: The early British Opposition.” Springer Basel AG (2010): n. pag. web. 2010.