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Neils Bohr.

posted Nov 23, 2016, 4:57 PM by Upali Salpadoru   [ updated Jul 21, 2019, 2:39 AM ]

Bohr.jpg


Neils Bohr

1885 -1962




A Danish stamp issued in 1963.


1885

Niels Bohr was born in Copenhagen, Denmark.

Father- Christian Bohr, a celebrated Physician.

Mother -Ellen Adler coming from a well educated rich family.


  Niels Bohr proposed a model for the hydrogen atom.
  He showed that the energy is transferred only in certain well defined quantities. 
  Electrons should move around  only in prescribed orbits. 
It was due to this that we know the properties of elements depend on the number of valency electrons.
  When jumping from one orbit to another with lower energy, a light is emitted. 
  Bohr's theory could explain why atoms emitted light in fixed wavelengths.

1891 Age 6 Yrs.

 Niel entered the Grammelholms school. In his class of about 20 students, he did well usually coming third or fourth..

1898 Age 12 Yrs.

His teacher found it difficult to cope up. He often found errors in his text books. It was his father who guided him in physics and mathematics more than the teachers.

“My interest in the study of physics was awakened while I was still in school, largely owing to the influence of my father”.

As a student he won a gold medal from the Academy of Sciences in Copenhagen for solving a physics problem.

1903 Age 18 yrs.  

Entered Copenhagen University.


1909 Age 24 yrs.  

Master's degree in Physics.

He was a passionate football player and used to play along with his brother Harald Bohr who represented the Danish national team.


1911Age 26 yrs.  

Obtained the PhD for his theoretical research on the    properties of the metals according to Max Planck's early quantum theory which described energy as tiny particles, or quanta.

On a post graduate scholarship he was selected to work at Cambridge, UK with Nobel Laureate J.J. Thomson. The association did not go according to expectations. He was not impressed by the research work there.   


1912 Age 27 yrs.

Bohr moved to Manchester to work with Sir Ernest Rutherford.



Fig.2.Bohr married Margrethe Nørlund.



He started working with Professor Rutherford  in Manchester and was able to make considerable improvements to the nuclear model of the atom.

The families of Bohr and Rutherford became intimate, life long friends.

1913 Age 28 yrs.  

Lecturer in Physics at Copenhagen University.


Fig.3.Courtesy: Encyclopedia Britannica.

According to him when the electrons absorb energy, they make an instant jump to a higher orbit. When they emit electromagnetic radiation they come down to a lower orbit.



The chemical element Bohrium , Bh, Atomic No. 107 was named after him.

This model came to be known as the Rutherford -Bohr model of the atom.                     

1914 Age 29 yrs.  

He became a lecturer at the  the Victoria University in Manchester.


1916 Age 31 yrs.

Became the  professor in theoretical physics at Copenhagen University.

1921 Age 35 yrs.

He founded The Institute of Theoretical Physics, which bears his name now.


1922 Age 37 yrs.

He was awarded the Nobel prize in Physics .

The Carlsberg brewery gave him a house, next to the brewery with a direct pipeline for free beer.


1926 to 1927  

Werner Heisenberg worked as an assistant to Bohr.

1927 Age 41 yrs.  

Along with Werner Heisenberg and other scientists he introduced  the quantum mechanics principle at an Italian conference.


He developed the concept of complementarity, a key principle in quantum mechanics. According to this certain properties cannot be observed or measured at the same time. A good example would be the nature of light which can be observed or measured as a wave or a particle but not at the same time.

Particles.jpg


Fig.4. Neils Bohr pondering over the thought experiments of Einstein.

Einstein was very reluctant to accept quantum mechanics. He continued to harass Bohr with thought experiments which Bohr used to answer defending the quantum theory.

He predicted the existence of a new element which was later found and named as hafnium , the latin name for Copenhagen.


1943 Age 58 yrs.   

He fled to Sweden and from there to  Britain as Nazis wanted to arrest him.

In Britain he worked on a nuclear weapons project and assisted the Manhattan project in America.         

MN.jpg
Fig.5. Mr and Mrs Bohr.

1954 Age 69 Yrs.

He played a major role in starting particle physics research facility, CERN.” Conseil Européen pour la Recherche Nucléaire.


1955 Age 70 Yrs.

He took a leading role at the ‘Atoms for Peace Conference.’

1957  Age 72 yrs.        

He got the “Atoms for peace award.”


1962 Age 77 Yrs.

Bohr died in Copenhagen.


1963

A Danish stamp honored Bohr on the 50th anniversary of his atomic theory.

Particles.jpg

Fig,6.

1975  

One of  his sons Aage Bohr, received the Nobel Prize.


The Nobel Prize in Physics was awarded jointly to Aage Niels Bohr, Ben Roy Mottelson and Leo James Rainwater "for the discovery of the connection between collective motion and particle motion in atomic nuclei and the development of the theory of the structure of the atomic nucleus based on this connection".


"During my early childhood, my parents lived at the Institute for Theoretical Physics (now the Niels Bohr Institute), and the remarkable generation of scientists who came to join my father in his work became for us children Uncle Kramers, Uncle Klein, Uncle Nishina, Unc  Uncle Heisenberg, Uncle Pauli, etc."







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