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Democritus
Democritus was born was born around 460 BC and died around 370 BC. He is creditied for discovering that all matter is made of atoms, although at the time no one paid attention to his theories. He was overshadowed by Arostotle, who believed that everything was made of either earth, water, wind, or fire. He discovered hyothesised atoms around 400 BC. -
John Dalton
He was born on September 6, 1766 and died July 27, 1844. He developed the first acceptable atomic theory in 1803. His theory consisted of 4 parts: 1) All matter is made of atoms. Atoms are indivisible and indestructible. 2) All atoms of a given element are identical in mass and properties. 3)Compounds are formed by a combination of two or more different kinds of atoms. 4) A chemical reaction is a rearrangement of atoms. -
J. J. Thomson
He was born December 18, 1856 and died August 30,1940. In 1897, he was the first person identify electrons as particles in atoms. Thomson and his team of scientists discovered that "cathode rays" were really unique particles and they are produced by all materials. Fun Fact Ernest Rutherford was a student of Thomson's at Cambridge. -
Marie Curie
Maire Curie and her husband, Pierre Curie, announced their discovery of a new element called "radium" on December 26, 1898. They named the element for its intense radioactivity. -
Radium
This element was discovered in 1898 by Marie and Pierre Curie. In 1909, Ernest Rutherford's experiment used radium as an alpha source to probe the atomic structure of gold. This experiment led to the Rutherford model of the atom and revolutionised the field of nuclear physics. -
Ernest Rutherford
He was born on August 30, 1871 and died October 19, 1937. He is known mostly for his infamous "gold foil" experiment. This proved that the nuclei of atoms are very dense, and that the vast majority of atoms is empty space. In addition, Rutherford discovered protons. -
Neils Bohr
Bohr was born on October 7, 1885, and died on November 18, 1962. His model of the atom is one we still use today, which includes up to 8 energy levels of electrons. He explained the structure of atoms as "successive orbital shells of electrons". -
Erwin Schrodinger
He was born August 12, 1887 and died January 4, 1961. He propsed the theory of an "electron cloud". This sort of built upon the ideas of Bohr, but in Schrondinger's model, there is not a specific place an electron will be at any time. The cloud is just a place surrounding the nucleus of probably places the electon may go. -
James Chadwick
He was born on October 20, 1891 and died on July 24, 1974. He discovered that there are neutrons in the nucleus of atoms, in addition to the protons. -
John Cockroft and Ernest Walton
Together, in 1932, they created a circuit design that performed the first artificial, nuclear disintegration is history. -
The Atomic Bomb
The atomic bomb was first tested on July 16, 1945. After years of extensive researched, scientist split atoms (First done by Cockroft and Walton) and figured out how to utilize the released energy to create massive explosions. The U.S. government ended World War 2 by dropping bombs on Hiroshima, Japan (August 6, 1945) and Nagasaki, Japan (August 15, 1945). -
Harold R. Kaufman
He was born in 1926. He is an American physicist, most famous for his development of the ion thruster in 1959, at the NASA Glenn facilities. The ion thruster use beams of ions to create thrust based on Newton's third law. This allows the thruster to use less fuel, yet still have more power. -
Deep Space 1
This was one of the most well-known missions to use the ion thruster. During a highly successful primary mission, it tested 12 advanced, high-risk technologies in space. In an extremely successful extended mission, it encountered Comet Borrelly and returned the best images and other science data ever from a comet.
