Niels Bohr

1
Niels Bohr

• -Niels Henrik David Bohr was bored in Copenhagen,
  Denmark on October 7, 1885 and died in Copenhagen
  on November 18, 1962

2
Family Heritage

• -Bohrs Father, Christian Bohr, was a professor of
  Physiology at the University of Copenhagen
• -Ellen Adler, his mother, came from a Jewish
  family
• -His brother, Herald, became a mathematician, and
  was thought to be a lot brighter then Niels in
  their younger years.
• -In August of 1912 Bohr married to Margrethe
  Norlund. They had six sons together, but two died
  at a very young age.

3
Bohrs Education Research

• -Bohr attended the University of Copenhagen in
  the year 1906.
• -On his first research project he won a gold
  medal from the Academy of sciences. His project
  involved precise measurement of the surface
  tension of water.
• -He received his PhD in the year 1911, and his
  dissertation was Studier over Metallerness
  Elektrontheori. Today it is still seen as a
  classic when it comes to the field of electron
  theory of metals.
• -A major bump in his education was the Cambridge
  Philosophical society rejected his dissertation.

4
Niel during the war

• -Niel remained in Copenhagen during the 40s when
  Hitler was in control. He left Denmark in the
  year 1943 and headed to Sweden.
• -During his stay in Sweden he helped many Jewish
  people from Hitlers gas oven.
• -He also came to the United States and worked on
  the atomic bomb at Los Alamos.

5
Bohrs work toward Quantum Theory

• -After his education he went to the Cavendish
  labs in Cambridge, England with hopes to work
  with J.J, Thompson, but J.J. Thompson had already
  lost interest.
• -After realizing J.J. Thompson had lost interest,
  Bohr moved to Manchester in the year 1912 to work
  with Rutherford.
• -Through his work with Ernest Rutherford they
  were able to lay the theory of atomic
  constitution.
• -Bohr and Rutherford used the solar system as a
  way to describe what the atom might look like
• -Rutherford had previously done an experiment in
  which he shot large alpha particles at a thin
  gold foil. When he did this he discovered that
  most of the light passed right through, but some
  actually went off at different angles (possibly
  deflected). This allowed him to conclude that
  most was made of empty space, but it did contain
  a space which was denser (where no alpha
  particles were able to pass through). Since this
  dense area deflected the positively charged alpha
  particles, he concluded this dense space had an
  overall positive charge.

6
Quantum Theory Cont

• -Bohr described how electrons would orbit around
  the nucleus, and how this represents different
  energy levels. He stated that an electron cannot
  exist between the energy levels, quantized energy
  levels. He said that the orbits which were closer
  to the nucleus had a lower energy then the orbits
  that were further from the nucleus.
• -Bohr also proposed that when energy is added to
  an electron , in the form of a photon, it can
  jump up to a higher energy level and moves
  further from the nucleus.
• -Bohr was able to explain how the electron went
  back down to a lower energy level , through
  photon emission. The difference in these energy
  levels would be the amount of energy released.
  The energy could be released in many different
  ways. It could be released in visible light,
  x-rays, or other parts of the electromagnetic
  spectra.
• -Bohrs idea of quantized energy levels fixed a
  major problem associated with the atom, but at
  the same time was slightly wrong with his idea of
  the amount of energy that is released when an
  electron drops energy levels. Bohrs idea seemed
  to work for hydrogen, but not for much larger
  atoms.
• -Erwin Schrodinger later proposed the idea that
  an electron could be both a wave and a particle.
  With this in mind he was able to find the
  probability of an electron being in a specific
  place.

7
Nobel Laureate

• -Bohr received the Noble Prize in the year 1922
  due to his work on atomic structure.