Niels Bohr was one of the key physicists of the 1900s. With his creative ideas and positive attitude, he uncovered a new side of science.

Niels Henrik David Bohr was born on October 7, 1885, in Copenhagen, Denmark. Christian Bohr, his father, was a physiology professor at the University of Copenhagen. Ellen Adler Bohr, Niels’s mother, was from a rich Jewish family involved in Danish banking. ( 7 )

While Bohr was young, his scientific talent  was obvious. His family encouraged him to reach his full potential in this area. Niels's brother was very bright, also. Harald Bohr became a famous mathematician. ( 7 )

Niels entered the University of Copenhagen in 1903. He studied physics there. He also played soccer, like his brother. Niels’s brother won a silver medal with the Danish soccer team in the 1908 Olympics. ( 1 ) Niels Bohr also received a special award. He  won a gold medal from the Royal Danish Academy of Sciences and Letters for his theoretical analysis of the vibrations of water jets to determine surface tension.

In 1909 Bohr received his Master’s degree, and in 1911 he earned his doctorate. Shortly after, Bohr went to Cambridge, England, to study with J. J. Thompson. (Thompson discovered the electron 15 years before.) Thompson showed little enthusiasm in Bohr’s studies. Because of this, Bohr moved to Manchester, England, to do research with Ernest Rutherford. Bohr hoped to find out more about the properties of matter and atoms.

Ernest Rutherford suggested the electron cloud model of the atom. In this model, an electron cloud surrounds a denser nucleus. Bohr knew that the electrons should, theoretically, lose energy and spiral toward the nucleus until they collide with it. Bohr suggested that quanta should be a part of the model. The idea of quanta, suggested by Max Planck in 1901, is that electrons are at set energy levels. The amount of energy electrons have determines their distance from the nucleus. If electrons gain energy, they jump to a higher energy level, thus moving farther from the nucleus. If electrons lose energy, they move closer to the nucleus. The model below is a diagram of Bohr's model of the atom. Energy levels are represented as n=1 through n=7. The circle in the center represents the nucleus.

Bohr’s model of the atom proved essentially correct, and he won the Nobel Prize for his quantum theory studies in 1922. This made 37-year-old Niels Bohr famous. Because of Bohr's discoveries, the futures of theoretical atomic physics and quantum physics  were changed. Also, his discoveries essentially began the nuclear age.

Niels Bohr proposed several other important concepts. He suggested the theory of the nucleus as a liquid drop. He realized the importance of the atomic number and saw that the physical and chemical properties of elements depend on the electrons in individual atoms. Bohr studied the series of lines in the spectrum of light produced by hydrogen. He stated that atoms don’t radiate light while in a stable state—they only do when in between stable states. Bohr came up with “complementarity.” This is also called wave-particle duality, which states that certain waves, like light, exhibit characteristics of waves and particles. However, we can only study one aspect at a time. (Louis de Broglie also is given credit for the discovery of complementarity.)

Bohr married Margrethe Nørlund in 1912. The couple had six children. One of their sons, Aage, also became a Nobel Prize-winner for his achievements in physics.

Bohr then returned to the University of Copenhagen-- as a professor. In 1920 he founded the Institute for Theoretical Physics. He was director of this institute for practically the rest of his life.

While Hitler controlled Germany, Niels Bohr offered a place for other physicists to reside and continue their studies. He donated his Nobel Prize medal to the Finnish war effort. ( 1 ) In 1939, he was informed that the Germans were trying to split the atom. ( 1 ) (Knowing this made him want to learn  even more about atoms and matter.) He shared this information with the United States. The U.S. then began the Manhattan Project to make an atomic bomb.

When Denmark was captured by Germany, Bohr fled to Sweden due to his Jewish ties. He traveled in a fishing boat with Margrethe and several other family members. Next, Niels and Aage were taken to England by a British warplane. The father-son duo then helped U.S. physicists work on the atomic bomb in Los Alamos, New Mexico.

Niels Bohr was concerned about the effects of atomic bombs. Bohr wanted to share nuclear information  with the Soviet Union. He also wanted nuclear weapons to be regulated.

Bohr organized the Atoms for Peace Conference, held in Geneva in 1955. ( 1 ) He helped begin CERN, the European Council for Nuclear Research, and he received the first ever Atoms for Peace Award.

Niels Bohr died on November 18, 1962, in Copenhagen. In 1997 element 107, bohrium, was named after him. Bohr was truly remarkable. Because of his work ethics and dedication, physics was changed forever.