Archive from December, 2012

Albert Einstein

The German-born American physicist Albert Einstein (1879-1955) revolutionized the science of physics. He is best known for his theory of relativity.

In the history of the exact science, only a handful of men—men like Nicolaus Copernicus and Isaac Newton—share the honor that was Albert Einstein’s the initiation of a revolution in scientific thought. His insights into the nature of the physical world made it impossible for physicists and philosophers to view that world as they had before. When describing the achievements of other physicist, the tendency is to enumerate their major discoveries, when describing the achievements of Einstein, it is possible, to say, simply, that he revolutionized physics.

Albert Einstein was born on March 14, 1879, in Ulm, but he grew up and obtained his early education in Munich. He was not a child prodigy, in fact, he was unable to speak fluently at age 9. Finding profound joy, liberation, and security in contemplating the laws of nature, already at age 5 he had experienced a deep feeling of wonder when puzzling over the invisible, yet definite, force directing the needle of a compass. Seven years later he experienced a different kind of wonder: the deep emotional stirring that accompanied his discovery of Euclidean geometry, with its lucid and certain proofs. Einstein mastered differential and integral calculus by age 16.

Education in Zurich
Einstein’s formal secondary education was abruptly terminated at 16. He found life in school intolerable, and just as he was scheming to find a way to leave without impairing his chances for entering the university, his teacher expelled him for the negative effects his rebellious attitude was having on the morale of his classmates. Einstein tried to enter the Federal Institute of Technology (FIT) in Zurich, Switzerland, but his knowledge of nonmathematical disciplines was not equal to that of mathematics and he failed the entrance examination. On the advice of the principal, he thereupon first obtained his diploma at the Cantonal School in Aarau, and in 1896 he was automatically admitted into the FIT. There he came to realized that his deepest interest and facility lay in physics, both experimental and theoretical, rather than in mathematics.

Einstein passed his diploma examination at the FIT in 1900, but due to the opposition of one of his professors he was unable to subsequently obtain the usual university assistantship. In 1902 he was enganged as a technical expert, third-class, in the patent office in Bern, Switzerland. Six months later he married Mileva Maric, a former classmate in Zurich. They had two sons. It was in Bern, too, that Einstein, at 26, completed the requirements for his doctoral degree and wrote the first of his revolutionary scientific papers.

Academic Career
These papers made Einstein famous, and Universities soon began competing for his services. In 1909, after serving as a lecturer at the University of Bern, Einstein was called as an associate professor to the University of Zurich. Two years later he was appointed a full professor at the German University in Prague. Within another year and a half Einstein became a full professor at the FIT. Finally, in 1913 the well-known scientists Max Planc and Walter Nernst traveled to Zurich to persuade Einstein to accept a lucrative research professorship at the University of Berlin, as well as full membership in the Prussian Academy of Science. He accepted their offer in 1914, quipping:”The Germans are gambling on me as they would on a prize hen. I do not really know myself whether I shall ever really lay another egg.” When he went to Berlin, his wife remained behind in Zurich with their two sons; after their divorce he married his cousin Elsa in 1917.

In 1920 Einstein was appointed to a lifelong honorary visiting professorship at the University of Leiden. During 1921-1922 Einstein, accompanied by Chaim Weizmann, the future president of the state of Israel, undertook extensive worldwide travels in the cause of Zionism. In Germany the attacks on Einstein began. Philipp Lenard and Johannes Stark, both Nobel Prize-winning physicists, began characterizing Einstein’s theory of relativity as “Jewish physics”. This callousness and brutality increased until Einstein resigned from the Prussian Academy of Science in 1933. (He was, however, expelled from the Bavarian Academy of Science).

Career in America
On several occasions Einstein had visited the California Institute of Technology, and on his last trip to the United States Abraham Flexner offered Einstein—on Einstein’s terms—a position in the newly conceived and funded Institute for Advanced Studies in Princeton. He went there in 1933.

Einstein played a key role (1939) in mobilizing the resources necessary to construct the atomic bomb by signing a famous letter to President Franklin D. Roosevelt which had been drafted by Leo Szilard and E.P. Wigner. When Einstein’s famous equation E=mc2 was finally demonstrated in the most awesome and terrifying way by using the bomb to destroy Hiroshima in 1945, Einstein, the pacifist and humanitarian, was deeply shocked and distressed; for a long time he could only utter “Horrible, horrible.” On April 18, 1955, Einstein died in Princeton.

Theory of Brownian Motion
From numerous references in Einstein’s writings it is evident that, of all areas in physics, thermodynamics made the deepest impression on him. During 1902-1904 Einstein reworked the foundations of thermodynamics and statistical mechanics; this work formed the immediate background to his revolutionary papers of 1905, one of which was on Brownian motion.

In Brownian motion (first observed in 1827 by the Scottish botanist Robert Brown), small particles suspended in a viscous liquid such as water undergo a rapid, irregular motion. Einstein, unaware of Brown’s earlier observations, concluded from his theoretical studies that such a motion must exist. Guided by the thought that if the liquid in which the particles are suspended consists of atoms or molecules they should collide with the particles and set them into motion, he found that while the particle’s motion is irregular, fluctuating back and forth, it will in time nevertheless experience a net forward displacement. Einstein proved that this net forward displacement of the suspended particles is directly related to the number of molecules per gram atomic weight. This point created a good deal of skepticism toward Einstein’s theory at the time he developed it (1905-1906), but when it was fully confirmed many of the skeptics were converted. Brownian motion is to this day regarded as one of the most direct proofs of the existence of atoms.

 

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