NIELS BOHR

                  Niels Henrik David Bohr  was a       Danish physicist who made foundational contributions to understanding atomic   structure and quantum theory, for which he received the Nobel Prize in Physics in 1922. Bohr was also a philosopher and a promoter of scientific research.

                 Bohr developed the Bohr model of the atom, in which he proposed that energy levels of electrons are discrete and that the electrons revolve in stable orbits around the atomic nucleus but can jump from one energy level (or orbit) to another. Although the Bohr model has been supplanted by other models, its underlying principles remain valid. He conceived the principle of complementarity: that items could be separately analysed in terms of contradictory properties, like behaving as a wave or a stream of particles. The notion of complementarity dominated Bohr's thinking in both science and philosophy.

In 1922, Niels Bohr was awarded the Nobel Prize in physics for his work to advance our understanding of atomic structure. Even though he is best known for the development of the Bohr model of the atom, he also accomplished many other things in his lifetime. He spent many years studying the atomic nucleus and how it could be fissioned to release energy. His research was used in the development of atomic weapons and nuclear energy, and he spent much of his later life working to promote the peaceful development of nuclear energy and addressing problems that arose from the development of atomic weapons during World War II. In recognition of his efforts for the responsible use of atomic energy, in 1957, Niels Bohr was awarded the Atoms for Peace Award.