Niels Bohr Theory and its famous quotes

SCIENCE OF AERONAUTICSAND

ENGINEERING EDUCATIONAL TECHNICS

Presented by :-CH. PURUSHOTHAM

Aeronautical Engineering

Niels Bohr(7th Oct 1885 to 18 Nov 1962)

Born in Copenhagen, Denmark on 7th October 1885, Niels Bohr was the second of three children of Christian Bohr and his wife Ellen Adler Bohr. His father was a renowned professor of physiology at the University of Copenhagen who was nominated twice for the Nobel Prize. Neil’s elder sister Jenny became a teacher while his younger brother Harald became a mathematician and footballer. Harald Bohr was part of the Danish soccer team at the 1908 Summer Olympics which won a silver medal and defeated France 17–1, which remains an Olympic record.

Bohr Family introduction

Niels Bohr did his early education at the Gammelholm Latin School in Copenhagen. He joined the Copenhagen University in 1903 to study physics, astronomy and mathematics at the undergraduate level. In 1910, he acquired his master’s degree in Physics. He then elaborated his master’s thesis into his Doctor of Philosophy thesis, which was accepted in April 1911 and soon after he received his PhD degree. Bohr’s doctoral dissertation was ground-breaking but didn’t get the attention it deserved as it was written in Danish. In it Bohr had discovered the Bohr–van Leeuwen theorem but it only came into focus when it was rediscovered by Dutch physicist Hendrika Johanna van Leeuwen in 1919.

Studies and his thesis

On August 1, 1912, Niels Bohr married Margrethe Nørlund, the sister of the Danish mathematician Niels Erik Nørlund. The couple had six sons. They lost a son to a boating accident in 1934 while another died from childhood meningitis. One of their sons, Ernest played field hockey for Denmark at the 1948 Summer Olympics. In 1975, Neils’ son, Aage Bohr, a nuclear physicist, won the Nobel Prize in Physics making the Bohrs one of only six pairs of fathers and sons to have won the Nobel Prize.

Life partner

Bohr’s atomic model was initially unacceptable to most physicists but as it was able to account for an ever-increasing experimental data it gained in popularity. Although the Bohr model of the atom has been superseded, its underlying principles remain valid. In 1922, Niels Bohr was awarded the Nobel Prize in Physics “ for his services in the investigation of the structure of atoms and of the radiation emanating from them”. The award was recognition for both the Trilogy and his work in the emerging field of quantum mechanics. Other awards given to Bohr include the Hughes Medal in 1921, the Matteucci Medal in 1923, the Franklin Medal in 1926 and the Copley Medal in 1938.

Niels Bohr was awarded Nobel Prize in Physics

Bohr’s atomic modelNeils Bohr presented his

atomic model retaining the basic idea of Rutherford’s model. The important postulates are:

1. Electrons revolve around the nucleus in definite, closed, circular paths called orbits.

2. Each orbit is associated with a definite amount of energy therefore also called as energy level.

3. These orbits or energy levels are numbered 1,2,3,4….. or K,L,M,N…. from inside onwards. Bigger the orbit, greater is the energy associated with it.

They are also called principal quantum levels, represented by ‘n’.

4. More than one energy levels are possible for an electron. However, as long as an electron is in an energy level its energy remains constant.

5. When an electron gains energy it jumps from lower energy level to higher.

6. When it jumps back from higher energy level to lower, it loses energy in the form of light.

7. The energy released ( E )can be calculated by:

Where ‘h’ is Planck’s constant, ‘v’ is the frequency of light emitted.

With the advent of World War II, Germany occupied Denmark in April 1940. Leading German physicist Werner Heisenberg travelled to German-occupied Copenhagen in September 1941. Heisenberg had been a student of Niels Bohr and collaborated with him. They met privately in the evening on September 17 but their conversation remains a mystery with both giving differing accounts. Heisenberg, though not an anti-Semitic, was a loyal German national and leader of the secret German nuclear program. Bohr would go on to warn the Allied Nations of Germany’s intention of preparing an atomic bomb, leading to enhancement in their efforts to accomplish the same while Heisenberg would opine to the Germans that preparing an atomic bomb was not feasible at the time.

Niels Bohr had a famous meeting with Werner Heisenberg

He was part of the Manhattan ProjectFrom Sweden, Niels Bohr was taken to London and from there he travelled to the U.S. as part of the British Mission to work on the top-secret Manhattan Project, a research and development project to produce nuclear weapons. Bohr joined the project as he was concerned about a corresponding project in Germany. He later said that they didn’t need my help in making the bomb. However Robert Oppenheimer, the “father of the atomic bomb”, credited Bohr for his technical contributions including solving the puzzle of a device known as modulated neutron initiators; and for being “a scientific father confessor to the younger men.”



Niels Bohr Famous Quotes



CH. PURUSHOTHAMAeronautical Engineering

An expert is someone who knows some of the worst mistakes, which can be

made,in a very narrow field.

Niels Bohr(7th Oct 1885 to 18 Nov 1962)



Every valuable human being must be a radical and a rebel, for what he must aim at is to make things better than they

are.

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Niels Bohr



A physicist is just an atom's way of looking at itself.

Niels Bohr

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The opposite of every great idea is another

great idea.Niels Bohr

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Nothing exists until it is measured.

Niels Bohr

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Every great and deep difficulty bears in itself its

own solution. It forces us to change our thinking in order

to find it. Niels Bohr

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Prediction is risky, especially of the

future. Niels Bohr

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Never express yourself more clearly than you are

able to think.Niels Bohr

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Truth is something that we can attempt to doubt, and then perhaps, after much

exertion, discover that part of the doubt is not

justified. Niels Bohr



A visitor to Niels Bohr's country cottage, noticing a horseshoe hanging on the wall, teasing the eminent scientist about this ancient superstition. "Can it be true that you, of all people, believe it will bring you luck?' 'Of course not,' replied Bohr, 'but I understand it brings you luck whether you believe it or not.'

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Niels Bohr Theory and its famous quotes