1915+-+1950

**__Werner Heisenberg__ **  **-Born in Würzberg, Germany on December 5, 1901. -Died in Munich, W. Germany on February 1, 1976. Werner Heisenberg is a German physicist and philosopher. In 1920, he studied physics in the University of Munich. Under Neils Bohr, he was chosen Lecturer in Theorectical Physics at the University of Copenhagen in 1926. One year later, he was selected Professor of Theoretical Physics at the University of Leipzig. In 1929 he went abroad to Japan, United States and India to give lectures. He was appointed director of the Kaiser Wilhelm Institute for Physics as well as professor of physics at the University of Berlin in 1941. At the end of World War II, Heisenberg and other German physicists were taken to prison by the American troops. Then, they were sent to England. In 1946 he returned to Germany and with his colleagues, he reorganized the Institute for Physics at Gottingen, which was renamed the Max Planck Institute for Physics and Astrophysics. In 1925, Heisenberg discovered a way to formulate quantum mechanics in terms of matrices. He examined another feature of quantum mechanics that is missing in classical mechanics. He published his uncertainty principle which states that is not possible to know exactly at the same time, both the velocity and the position of a particle. This limitation applies for small particles such as electrons, but not for ordinary sized objects like cars. This discovery of matter paved the way for Erwin Schrödinger’s quantum mechanical description of electrons in atoms. Schrödinger’s theory includes the wavelike motion of matter as well as the uncertainty principle. On the other hand, Heisenberg made significant contributions to the theories of hydrodynamics of turbulent floes, ferromagnetism, the atomic nucleus, subatomic particles and cosmic rays. Heisenberg was involved in the preparation of the first West German nuclear reactor at Karlsruhe and a research reactor in Munich. Great argument surrounds his work on atomic research during WWII. **
 * __1915 - 1950__ **

 
 * __Erwin Schrödinger__**

**-Born on August 12, 1887 in Vienna, Austria -Died in Alpbach, Austria on Jan. 4, 1961 Erwin Schrödinger was a bright, experimental and theoretical physicist. During the first half of the 20th century, he worked in Vienna and Berlin. Schrödinger was a major contributor to the wave theory of matter (a form of quantum physics). He developed a mathematical equation of wave mechanics that has his name. Erwin’s investigation was interrupted by two world wars. However, he still made advances in both quantum and color theory. In 1926, Erwin Schrödinger developed a mathematical equation to describe the movement of electrons in atoms or the behavior of the electron in a hydrogen atom. His work leads to the electron cloud model. The current explanation of electrons in atoms, the quantum mechanical model, comes from the mathematical solutions to his equation. This model determines the allowed energies an electron can have and how prone it is to find the electron in diverse locations around the nucleus. **

__Electron Cloud Model__ **
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**The electron cloud model is a visual model of the probable place of electrons in an atom. The probability of finding an electron is higher in the denser regions of the cloud. The nucleus contains protons and neutrons. Werner Heisenberg’s uncertainty principle contributed to the idea of the electron cloud model. His principle states that it is not possible to obtain precise values of both velocity and position of a particle at the same time. Heisenberg determined that the only way to describe the location of an electron in an atom is through probability distribution. This principle forms the basis of the electron cloud model. Erwin Schrödinger also contributed to the electron cloud model. He developed mathematical equations to describe the motion of electrons in atoms. Hence, his work also leads to the electron cloud model.

 __James Chadwick__

-Chadwick was born on October 20 1891. He was born in England and when he had graduated, it was with honors from a school of physics in 1911. He was prisoner of WW1 for four years before he went back to England to find his mentor. He studied under Rutherford for 2 years and he worked on a lot of experiments on raidio activities. Chadwicke helped Rutherford in transmuting the element. In 1932 he becuame very femous becuase of his discovery for the neutron. in 1943-66 he worked with the USA as the hed of the british museaums in a mission attched to the Manattan Project for the develpment of atomic boms. after this, he went back to sdyuin en english. As his experimented less, he was constantly joining clubs and societies where he was recognized for his discoery and led to experimenting more. During that time of societies and clubs and recognition, he got married and had twins. his life was not to active after he married, he had more responsabilities nd e did not hve as much time as he had befor in the lab. Chadwick died on July 24, 1974.** **Chadwick's main change to the atomic theory was the discovery of the neutron particles in the nucleus of an atom. Rutherford had sugested that such thing like a neutron could exist yet he had not proven it. Chadwick had not really payed much attention to Rutherford's idea. At that time in Europe, Frederic and Irene- Joliot Curie were exprerimenting with tracking paarticle radiation and the way was dfferent so Chadwick decided to try it and that was when he discovered the neutron which was 0.1 % heavier than the regular proton.**