Niels Bohr

Introduction & Top Questions
Early life
Bohr atomic model
Bohr’s Institute for Theoretical Physics
Nobel Prize
Copenhagen interpretation of quantum mechanics
Nuclear physics
Splitting the atom
Helping the refugees
The atomic bomb
An “open world”

References & Edit History Quick Facts & Related Topics

Images & Videos

Diagram of the Bohr atomic model showing an electron moving in circular orbits with quantized energy levels around a central nucleus, alongside an energy level diagram illustrating electron transitions.

Know about the element of uncertainty of nature in Niels Bohr's interpretation of quantum theory and its success despite Albert Einstein's objections

Learn about Niels Bohr and the difference of opinion between Bohr and Albert Einstein on quantum mechanics

A hand places a dark glove into a metal box lined with white tissue, set on grass, illustrating a concept related to quantum mechanics and the uncertainty principle.

Niels Bohr's contribution to atomic theory explained

At a Glance

Niels Bohr summary

Quizzes

Michael Faraday (L) English physicist and chemist (electromagnetism) and John Frederic Daniell (R) British chemist and meteorologist who invented the Daniell cell.

Faces of Science

Italian-born physicist Dr. Enrico Fermi draws a diagram at a blackboard with mathematical equations. circa 1950.

Physics and Natural Law

Related Questions

How did Arnold Sommerfeld modify the Bohr model?
How did Ernest Rutherford’s nuclear model influence Niels Bohr’s atomic theory?
How did J. Robert Oppenheimer describe Niels Bohr’s role among younger scientists at Los Alamos?
How did Niels Bohr travel from occupied Denmark to Sweden?
How did Niels Bohr’s father influence his early academic environment?
How did Niels Bohr’s institute support younger physicists with new ideas?
How did Niels Bohr’s view of the Allied atomic bomb project change after he reached England?
How did Planck’s constant contribute to Niels Bohr’s atomic model?
How did atoms absorb light according to the Bohr model?
How did electrons emit light according to the Bohr model?
How did the Bohr model differ from the Rutherford model?
How did the Bohr model explain why electrons do not fall into the atomic nucleus?
How did the Franck-Hertz experiment support the idea of discrete atomic energy states?
How did the Stern-Gerlach experiment provide evidence for quantized angular momentum?
How many children did Niels and Margrethe Bohr have?
What are stationary states in Niels Bohr’s atomic theory?
What did Niels Bohr ask the United Nations to support in his 1950 open letter?
What does Niels Bohr’s complementarity principle say about light and electrons?
What does the quantum number n represent in the Bohr model?
What features of hydrogen spectra could the original Bohr model not explain?
What subject did Niels Bohr examine in his 1911 doctoral dissertation?
What technical contribution did Niels Bohr make to the plutonium bomb project?
When and where was Niels Bohr born?
When did Niels Bohr and Albert Einstein debate quantum mechanics at the Solvay Conferences?
When did Niels Bohr become a professor at the University of Copenhagen?
When did Niels Bohr publish his model of the atom?
When was Niels Bohr’s Institute for Theoretical Physics inaugurated?
Where did Niels Bohr study physics as a university student?
Which British prime minister did Niels Bohr meet to discuss international cooperation on atomic weapons?
Which Niels Bohr son later won a Nobel Prize in Physics?
Which U.S. president did Niels Bohr meet during his campaign for an open world?
Which hydrogen spectral series lies in the visible part of the spectrum?
Which major European science organizations did Niels Bohr help establish after World War II?
Which physicist developed the uncertainty principle while working as Niels Bohr’s assistant?
Who discovered hafnium while working at Niels Bohr’s institute?
Who were Niels Bohr’s parents?
Whom did Niels Bohr marry in 1912?
Why could electrons occupy only certain orbits in the Bohr model?
Why could the Bohr model not fully explain atoms with more than one electron?
Why did Niels Bohr escape from Denmark in 1943?
Why did Niels Bohr initially think an atomic bomb could not be built during World War II?
Why did Niels Bohr urge the Allies to inform the Soviet Union about the atomic bomb project?
Why did classical physics predict that Rutherford’s orbiting electrons would be unstable?
Why did the Bohr model successfully explain hydrogen’s spectral lines?
Why was element 72 named hafnium?
What was Niels Bohr’s most important discovery?
Who is C.V. Raman?
What did Marie Curie accomplish?
What awards did Marie Curie win?
Why was Marie Curie important?
What is Marie Curie most famous for?
What did Marie Curie discover?
How did Marie Curie die?
What is Richard Feynman famous for?
What is Michel H. Devoret known for?

Science Physics Physicists

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External Websites

Atomic Archive - Niels Bohr
LiveScience - Niels Bohr: Biography and Atomic Theory
NPR - Einstein, Bohr, And Ultimate Reality : 13.7: Cosmos And Culture
The Information Philosopher - Niels Bohr
IOPSpark - Bohr
Famous Scientists - Biography of Niels Bohr
BBC Sounds - Human Intelligence - Manhattan Project: Niels Bohr
The Nobel Prize- Biography of Niels Bohr
Molecular Expressions - Biography of Niels Henrik David Bohr
Jewish Virtual Library - Niels Bohr
PBS - A Science Odyssey : People and Discoveries - Niels Bohr
Niels Bohr Institute - Niels Bohr
AIP Publishing - Physics Today - Niels Bohr between physics and chemistry

Britannica Websites

Articles from Britannica Encyclopedias for elementary and high school students.

Niels Bohr - Children's Encyclopedia (Ages 8-11)
Niels Bohr - Student Encyclopedia (Ages 11 and up)

Niels Bohr

Danish physicist

Also known as: Niels Henrik David Bohr

Written by

Finn Aaserud

Director of the Niels Bohr Archive. Author of Redirecting Science: Niels Bohr, Philanthropy, and the Rise of Nuclear Physics.

Finn Aaserud

Fact-checked by

Britannica Editors

Encyclopaedia Britannica's editors oversee subject areas in which they have extensive knowledge, whether from years of experience gained by working on that content or via study for an advanced degree....

Britannica Editors

Last updated

Oct. 3, 2026 •History

Niels Bohr (born October 7, 1885, Copenhagen, Denmark—died November 18, 1962, Copenhagen) was a Danish physicist who is generally regarded as one of the foremost physicists of the 20th century. He was the first to apply the quantum concept, which restricts the energy of a system to certain discrete values, to the problem of atomic and molecular structure. For that work he received the Nobel Prize for Physics in 1922. His manifold roles in the...

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