Κυριακή, 9 Μαΐου 2010

Δεκαοκτώ (37-54) από 54 διάσημους Φυσικούς, αλφαβητικά.

37) Lise Meitner (1878-1968) Birthplace: Vienna, Austria
Throughout the 1920s and early 1930s, Meitner worked in Berlin doing experimental research in nuclear physics, but went into exile in 1938 to escape the Nazis. In Sweden, she received information about work done by her former colleague Otto Hahn, who was continuing their research with what they considered to the transuranic elements. Meitner realized that the explanation instead was nuclear fission. The atomic age had began.

38) Albert Michelson (1852-1931) Birthplace: Strelno, Poland
(Nobel Prize: 1907)
The interferometer that this superb experimentalist invented has been a basic tool in many different investigations. Michelson used it to measure the standard meter in terms of the wavelengths of light, and to see if the speed of light depends on the motion of the Earth through the ether. Although the Michelson – Morley experiment is now considered one of the proofs of Einstein’s relativity theory, Michelson himself was never satisfied with its null result.

39) Robert Millikan (1836-1953) Birthplace: Morisson, IL
(Nobel Prize: 1923)
Robert Millican was an outstanding teacher and textbook author (the AAPT award for notable contributions to physics teaching is named for him). However, he is the best known for his series of experiments on charged oil drops by which he determined the electron charge. His other contributions to physics include the experimental verification of Einstein’s photoelectric equation and the determination of Planck’s constant. His studies of Brownian motion in gases put an end to all opposition to the atomic and kinetic theories of matter.

40) Isaac Newton (1642-1727) Birthplace: Lincolnshire, England
Inventor of the calculus, creator of laws of dynamics, framer of the law of universal gravitation, discoverer of many optical phenomena. And yet he said, “I do not Know what I may appear to the world, but to myself, I seen to have been only like a boy playing on the seashore and diverting myself in now and then finding a smoother pebble ar a prettier shell than ordinary, why the great Ocean of Truth lay all undiscovered before me.”

41) H. Kamerlingh Onnes (1853-1926) Birthplace: Groningen, The Netherlands
(Nobel Prize: 1913)
Kamerlingh Onnes was the first to liquify helium. He conducted extensive studies of the properties of materials at temperatures of 4K and lower. Among his discoveries was that at sufficiently low temperatures the electrical resistance of certain metals vanishes. In 1901, Albert Einstein attempted unsuccessfully to obtain a position at Kamerlingh Onnes’ laboratory.

42) Wolfgang Pauli (1900-1958) Birthplace: Vienna, Austria
(Nobel Prize: 1945)
Pauli was of the inventors and refiners of the quantum theory. His exclusion principle was the key to understanding the periodic table of elements. Typical of his acerbic but valuable style was his comment when he was 20 years old and attending a colloquium where Einstein was the speaker. Said Pauli, “What Professor Einstein has said is not all that stupid.” He was in a position to know; he had just written a definitive survey of Einstein’s special theory of relativity for an encyclopedia of mathematics.

43) Jean Baptiste Perrin (1870-1942) Birthplace: Lille, France
(Nobel Prize :1926)
In 1895 Perrin demonstrated that cathode rays of negatively charged particles. He later measured the vertical distribution of colloidal particles undergoing Brownian motion. His results were consistent with the theoretical results of Einstein and Smoluchowski on Brownian motion and provided proof of the existence of atoms.

44) Max Planck (1858-1947) Birthplace: Kiel, Germany
(Nobel Prize: 1918)
Max Planck developed a rather simple relationship of blackbody radiation over all wavelengths. The equation was based on the assumption that energy can only be emitted or absorbed in discrete amounts, which he called “quanta”. The energy of a quantum of electromagnetic radiation is proportional to the radiation frequency, and the proportionality constant later became known as Planck’s constant.

45) Jules Henri Poincare (1854-1912) Birthplace: Nancy, France
Poincare was equally at home in mathematics and physics. He invented the qualitative theory of differential equations, which is the foundation for today’s approach to nonlinear mechanics and “chaos”. In retrospect, some of his work seems to have anticipated Einstein’s special theory of relativity, though lacking the powerful simplicity of Einstein’s formulation.

46) Isidor I. Radi (1898-1988) Birthplace: Raymanov, Austria
(Nobel Prize: 1944)
From a childhood spent in the immigrant tenements of New York, Radi rose to be one of the dominant figures in American physics during the mid-20th century. He invented and exploited atomic beam techniques to measure fundamentals constants of nuclei, atoms, and molecules. His work is the foundation for such allpications as atomic clocks and nuclear magnetic resonance.

47) Lord Rayleigh (1842-1919) Birthplace: Essex, England
(Nobel Prize: 1904)
“Tell me why the sky’s so blue.” It’s Rayleigh scattering. John William Strutt, third Baron Rayleigh, skilled experiment and discovered of argon, explained a vast number of sound and light. Indded, many of his mathematical techniques apply to problems in quantum mechanics.

48) Ernest Rutherford (1871-1937) Birthplace: Nelson, New Zeland
(Nobel Prize: 1908, Chemistry)
Master of research with natural radioactivity. Discovered of atomic nucleus. “Lucky fellow,” a friend once said to him. “Always riding the crest of the wave.” “Yes,” answered Rutherford, “but I made the wave.”

49) Erwin Schrodinger (1887-1961) Birthplace: Vienna, Austria
(Nobel Prize: 1933)
The Schrodinger wave equation is the starting point of the most calculations in quantum mechanics. The “waves” are not the “particles,” nor do they describe the motion of the particles. Instead the solutions to the equation are probability functions that (properly combined) give the probability of the particle being in certain positions or having certain properties.

50) Leo Szillard (1898-1995) Birthplace: Budapest, Hungry
Soon after discovery of nuclear fission, Leo Szillard conducted experiments to determine if neutrons are released in the process. The positive result indicated that a nuclear fission chain reaction was possible. He and Fermi developed the first nuclear reactor and they were jointly awarded a patent for the design. It was Szilard who drafted Einstein’s famous letter to President F.D. Roosevelt that ultimately led to the initiation of the Manhattan Project.

51) Charles H. Townes (1915- ) Birthplace: Greenville, SC
(Nobel Prize: 1964)
Townes received the Nobel Prize in physics for his work in quantum electronics. He expanded the uses of atomic and molecular beams to produce masers, the forerunners of lasers and atomic clocks. As a pioneer in infrared astronomy, he discovered that there are many complex molecules in space.

52) Hermann Weyl (1885-1955) Birthplace: Elmshorn, Germany
Mathematician, physicist, philosopher, and teacher, Weyl wrote the books that introduced many physicists to quantum theory and relatively. His most famous work concerned symmetry in physics. He saw the relevance of gauge theory, which was later shown by others to underlie all present physical theory.

53) Eugene Winger (1902-1995) Birthplace: Budapest, Hungary
(Nobel Prize: 1963)
Winger was awarded the Nobel Prize “for his contributions to the theory of the atomic nucleus and the elementary particles, particularly though the discovery and application of fundamental symmetry principles.” He determined that the force that binds nucleons together is short – range and independent of the particles’ electric charge. He also developed the theory of neutron absorption, which was invaluable in the design of nuclear reactors.

54) Chien – Shiung Wu (1912-1997) Birthplace: Shanghai, China
Wu was a skilled experimenter in atomic and nuclear physics. Her specially concerned processes involving beta decay. When Yang and Lee proposed that parity is not conserved in weak interactions, Wu led a team to test the proposal. With a clever and delicate experiment involving low temperatures and nuclear detectors, she showed that parity was not conserved.

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