Important historic dates in science

February 29: Bohr's nucleus
In 1936, Nature carried Niels Bohr's "bowl of balls" explanation for the effect of bombarding particles on a nucleus.

February 29: Lawrence's Nobel speech
In 1940, Ernest O. Lawrence delivered his Nobel Prize acceptance speech in Berkeley, California, having arranged to receive the prize there, rather than Sweden, so that he would not lose any time away from the task of fund raising for his cyclotron research.

February 28: Steven Chu
(Born February 28, 1948)
American physicist who (with Claude Cohen-Tannoudji and William D. Phillips) was awarded the 1997 Nobel Prize for Physics for their independent, pioneering research in cooling and trapping atoms using laser light. In their normal state the constant random thermal motion of atoms limits the precision of measurements of atomic states. Thus, physicists have sought to cool and slow atoms down as much as possible. Chu used six laser beams and worked with a hot gas of sodium atoms. He managed to cool and trap atoms in what he called "optical molasses." By 1985, he had cooled sodium atoms to a temperature of about 240 millionth of a degree above absolute zero. The atoms could be trapped in the laser beams for a period of about half a second.

February 27: Neutron
In 1932, the neutron was discovered by Dr. James Chadwick.

February 26: Radioactivity
In 1896, Henri Becquerel stored a phosphorescent uranium compound in a closed desk drawer on top of a photographic plate awaiting a sunnier day to test his idea that sunlight would make the phosphorescent uranium emit rays. It remained there several days. Thus by accident, he created a new experiment, for when he developed the photographic plate, he found a fogged image in the shape of the rocks. The material was spontaneously generating and emitting the energetic rays totally without the external sunlight source. This was a landmark event. The new form of penetrating radiation was the discovery of the effect of radioactivity.

February 25: Glenn T. Seaborg
(Born April 19, 1912: Died February 25, 1999)
American nuclear chemist. During 1940-58, Seaborg and his colleagues at the University of California, Berkeley, produced nine of the transuranic elements (plutonium to nobelium) by bombarding uranium and other elements with nuclei in a cyclotron. He coined the term actinide for the elements in this series. The work on elements was directly relevant to the WW II effort to develop an atomic bomb. It is said that he was influential in determining the choice of plutonium rather than uranium in the first atomic-bomb experiments. Seaborg and his early collaborator Edwin McMillan shared the 1951 Nobel Prize for chemistry. Seaborg was chairman of the US Atomic Energy Commission 1962-71. Element 106, seaborgium (1974), was named in his honour.

February 24: Uranium
In 1896, Henri Bequerel told the French Academy of Sciences of his investigation of the phosphorescent rays of some "double sulfate of uranium and potassium" crystals. He reported that he placed the crystals on the outside of a photographic plate wrapped in sheets of very thick black paper and exposed the whole to the sun for several hours. When he developed the photographic plate, he saw a black silhouette of the substance exposed on the negative. When he placed a coin or metal screen between the uranium crystals and the wrapped plate, he saw images of those objects on the negative. He does not know yet that he has accidentally discovered radioactivity, or that the sun is not necessary to initiate the rays.

February 23: Allan MacLeod Cormack
(Born February 23, 1924: Died May 7, 1998)
South African-born American physicist who formulated the mathematical algorithms that made possible the development of a powerful new diagnostic technique, the cross-sectional X-ray imaging process known as computerized axial tomography (CAT) scanning. He first described this in two papers in 1963 and 1964. X-ray tomography is a process by which a picture of an imaginary slice through an object (or the human body) is built up from information from detectors rotating around the body. For this work, he was awarded a share of the 1979 Nobel Prize. Cormack was unusual in the field of Nobel laureates because he never earned a doctorate degree in medicine or any other field of science.

February 22: Fritz Strassmann
(Born February 22, 1902: Died April 22, 1980)
German physical chemist who, with Otto Hahn and Lise Mietner, discovered neutron-induced nuclear fission in uranium (1938) and thereby opened the field of atomic energy used both in the atomic bomb for war and in nuclear reactors to produce electricity. Strassmann's analytical chemistry techniques showed up the lighter elements produced from neutron bombardment, which were the result of the splitting of the uranium atom into two lighter atoms. Earlier in his career, Strassmann codeveloped the rubidium-strontium technique of radio-dating geological samples.

February 21: George Ellery Hale
( Born June 29, 1868; Died February 21, 1938)
American astronomer known for his development of important astronomical instruments, including the Hale telescope (completed 1948), a 200-inch reflecting telescope at the California Institute of Technology's Palomar Mountain Observatory near Pasadena. He is known also for his researches in solar physics, particularly his discovery of magnetic fields in sunspots.

February 20: Artificial Radioactivity
In 1934, spurred by a report by Frédéric Joliot concerning the probability that many elements could become radioactive upon hydrogen ion bombardment, Ernest O. Lawrence and his team began bombarding nitrogen in their cyclotron. Sure enough, they produced a new radioactive substance, and realized how during years of prior research with the cyclotron Lawrence had invented, they had never checked for any radioactivity resulting from the products of hydrogen bombardment. Thus Joliot was the first to discover artificial radioactivity, and Lawrence's group confirmed it.

February 19: 1984 - USSR performs nuclear test at Eastern Kazakh/Semipalitinsk USSR

February 18: Isotope
In 1913, chemist Frederick Soddy introduced the term "isotope". Soddy was an English chemist and physicist who received the Nobel Prize for Chemistry in 1921 for investigating radioactive substances. He suggested that different elements produced in different radioactive transformations were capable of occupying the same place on the Periodic Table, and on February 18, 1913 he named such species "isotopes" from Greek words meaning "same place." He is credited, along with others, with the discovery of the element protactinium in 1917.

February 17: British Atom Bomb Announced
In 1952, Winston Churchill announced that Britain had developed its own atomic bomb. The test for the first British-made atomic bomb was planned at the Monte Bello Islands off the northwest coast of Australia. The formal postwar decision to manufacture a British atomic bomb had been made by Prime Minister Clement Attlee's government early in Jan 1947 during a meeting of the Defence Subcommittee of the Cabinet. On February 25, 1952, at Sellafield on the Irish Sea coast in Cumberland, the Windscale plutonium plant began operation. On 3 Oct 1952, the first British atomic weapons test, called Hurricane, was successfully conducted aboard the frigate HMS Plym. Britain was was the third nuclear power after the U.S. and Russia to include the atomic bomb in its armoury.

February 16: 1977 - USSR performs nuclear test at Sary Shagan USSR
1966 - France performs underground nuclear test at Ecker Algeria
1961 - China uses it's 1st nuclear reactor

February 15: Herman Kahn
(Born February 15, 1922; Died July 7, 1983)
American physicist, military analyst (1948-61) and futurist best known for his controversial studies of nuclear warfare. Kahn won recognition for his dispassionate analysis of nuclear war in his books On Thermonuclear War (1960) which still, in its detached analysis of various nuclear-war scenarios, retains the power to shock.and Thinking About the Unthinkable (1962) which predicted the probability and survivability of nuclear war. Later books included the optimistic The Year 2000 (1967) and Why ABM? (1969). In 1961 he founded the influential Hudson Institute in New York to make reasoned predictions on world affairs, from narcotics policy to global economics, energy, international trade, population, transportation, crime, medicine.

February 14: C.T.R. Wilson
(Born February 14, 1869; Died November 15, 1959)
Scottish physicist who, with Arthur H. Compton, received the Nobel Prize for Physics in 1927 for his invention of the Wilson cloud chamber, which became widely used in the study of radioactivity, X rays, cosmic rays, and other nuclear phenomena. His discovery was a method of rendering visible the tracks of such electrically charged particles. It is based upon the formation of clouds, which develop when sufficiently moist air is suddenly expanded, thus dropping the temperature below the dew-point. Thereafter, vapour condenses into small drops, formed round dust particles, or even, an electrically charged atomic particle. The formation of droplets is so dense that photographs show continuous tracks of particles travelling through the chamber as white lines.

February 13: French Atomic Bomb
In 1960, France detonated their first plutonium bomb from a 330-foot tower at the Reggane base in the Sahara in what was then French Algeria. On October 18, 1945, the Atomic Energy Commission (Commissariat à l'Énergie Atomique; CEA) had been established by General Charles de Gaulle with the objective of exploiting the scientific, industrial, and military potential of atomic energy. On July 22, 1958, de Gaulle, having resumed power as prime minister, had set the date for the first atomic explosion to occur within the first three months of 1960. His goal was to assert France's independence and its role on the world stage. Thus he set about building the country's nuclear capacity acquiring also nuclear-armed aircraft, missiles and submarines.

February 12: Pierre-Louis Dulong
(Born February 12, 1785; Died July 18, 1838)
Chemist and physicist who helped formulate the Dulong-Petit law of specific heats (1819), which proved useful in determining atomic weights.

February 11: Leo Szilard
(Born February 11, 1898; Died May 30, 1964)
Hungarian-born American physicist who, with Enrico Fermi, designed the first nuclear reactor that sustained nuclear chain reaction (2 Dec 1942). In 1933, Szilard had left Nazi Germany for England. The same year he conceived the neutron chain reaction. Moving to N.Y. City in 1938, he conducted fission experiments at Columbia University. Aware of the danger of nuclear fission in the hands of the German government, he persuaded Albert Einstein to write to President Roosevelt, urging him to commission American development of atomic weapons. In 1943, Major General Leslie Groves, leader of the Manhattan Project designing the atomic bomb, forced Szilard to sell his atomic energy patent rights to the U.S. government.

February 11: Atomic Fission
In 1939, the journal Nature published a theoretical paper on nuclear fission. The term was coined by the authors Lise Meitner and Otto Fritsch, her nephew. They knew that when a uranium nucleus was struck by neutrons, barium was produced. Seeking an explanation, they used Bohr's "liquid drop" model of the nucleus to envision the neutron inducing oscillations in a uranium nucleus, which would occasionally stretch out into the shape of a dumbbell. Sometimes, the repulsive forces between the protons in the two bulbous ends would cause the narrow waist joining them to pinch off and leave two nuclei where before there had been one. They calculated calculated the huge amounts of energy released. This was the basis for nuclear chain reaction.

February 10: Wilhelm Conrad Röntgen (discovery of X-rays)
(Born May 27, 1845; Died February 10, 1923)
(also spelled Roentgen) German physicist who was a recipient of the first Nobel Prize for Physics, in 1901, for his discovery of X rays, which heralded the age of modern physics and revolutionized diagnostic medicine.

February 9: Japanese nuclear accident
In 1991, Japan's worst nuclear accident happened at Mihama. A pipe in the steam generator burst, leaking 55 tonnes of radioactive primary (reactor) coolant water into the secondary steam-generating circuit. Some radioactivity was released to the atmosphere and the plant's emergency core cooling system was activated. MITI reported later that the accident was caused by human error, some anti-vibration bars being wrongly installed by workers and sawn off short to make them fit. The release of radiation into the atmosphere was kept to a small amount. No deaths resulted. Various measures were taken to prevent the recurrence of the accident, including the replacement of the steam generators.

February 8: Walther Bothe
(Born January 8, 1891; Died February 8, 1957)
Walther Wilhelm Georg Bothe was a German physicist who developed the coincidence method of detecting the emission of electrons by x-rays in which electrons passing through two adjacent Geiger tubes at almost the same time are registered as a coincidental event. He used it to show that momentum and energy are conserved at the atomic level. In 1929 he applied the method to the study of cosmic rays and was able to show that they consisted of massive particles rather than photons. This research brought him a share (with Max Born) in the Nobel Prize for 1954. In 1930, he observed a strange radiation emitted from beryllium when it was exposed to alpha particles, later identified by Chadwick as consisting of neutrons. He built Germany's first cyclotron (1943).

February 7: Neutron
In 1932, the "neutron" was described in an article in the journal Nature by its discoverer, James Chadwick, who coined the name for this neutral particle present in the nucleus of atoms.

February 6: Spanish chemist Fausto Elhuyer dies
(Born October 11, 1755; Died February 6, 1833)
Fausto (d') Elhuyar (y de Suvisa) was a Spanish chemist and mineralogist who in partnership with his brother Juan José was the first to isolate tungsten metal, or wolfram (1783), though not the first to recognize its elemental nature. It was in 1781 that the Swedish chemist, Carl Scheele discovered tungstic acid from a mineral now known as scheelite, but which had been known since about 1758 as tung sten (Swedish, heavy stone). The Elhuyar brothers found the tungstic acid in the ore wolframite, and extracted the metal by reducing this acid with charcoal. They achieved it at the Seminary of Bergara and, for the first time, the names of Basque persons would be written in annals of the history of science.

February 5: Nobel Prize recipient Robert Hofstadter was born
(Born February 5, 1915; dies November 17, 1990)
American scientist who was a joint recipient of the Nobel Prize for Physics in 1961 for his investigations in which he measured the size of the neutron and proton in the nuclei of atoms. He revealed the hitherto unknown structure of these particles and helped create an identifying order for subatomic particles. He also correctly predicted the existence of hte omega-meson and rho-meson. He also studied controlled nuclear fission. Hofstadter was one of the driving forces behind the creation of the Stanford Linear Accelerator. He also made substantial contributions to gamma ray spectroscopy, leading to the use of radioactive tracers to locate tumors and other disorders. (He shared the prize with Rudolf Ludwig Mössbauer of Germany.)

February 4: In 1936, the first radioactive substance to be produced in the U.S. synthetically was radium E, by bombarding the element bismuth with neutrons. This was achieved by Dr. John Jacob Livingood at the University of California at Berkeley.

February 3: William D. Coolidge- American engineer and physical chemist
(Born October 23, 1873; Died February 3, 1975)
William David Coolidge was an American engineer and physical chemist whose improvement of tungsten filaments (1913, patent No.1,082,933) was essential in the development of the modern incandescent lamp bulb and the X-ray tube. Coolidge's X-ray tube (1916, U.S. patent No. 1,203,495) completely revolutionized the generation of X-rays and remains to this day the model upon which all X-ray tubes for medical applications are patterned. He worked on many other devices such as high-quality magnetic steel, improved ventilating fans, and the electric blanket. During World War II he contributed research to projects involving radar and radar countermeasures. He was awarded 83 patents during his lifetime.

February 2: In 1951- The US performs nuclear test at Nevada Test Site.

February 2: In 1954 - President Eisenhower reports detonation of 1st H-bomb (done in 1952).

February 1: In 1951, the first X-ray moving picture process was demonstrated.

February 1: In 1951, the TV station KTLA broadcast of an atomic explosion was the first to be seen publicly on television. The event was captured by an NBC camera on Mount Wilson, 300 miles away from the test blast at Frenchman Flats, Nevada.

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