T.+Patton+Big+Time+Line+Project

=__Big Time Line Project : History of the Atom__=

By Thomas Patton
=__Historic Events__= Antient times: Great Pyrimids are built, Alexander the great conquers Persian empire, Chritianity becomes officail religion or roman empire 500-1800: Buddhism is introduced to japan, Islamic armies invade spain, Crusaders capture Jerusalem, Columbus reaches caribbean, american Revolutionary war 1800-1875: 1875-1900: Triple Aliance 1900-1915: Henri for builds model A, WWI starts, 1915-1950: end of WWI, The Depresion, Hitler comes to power,WWII 1950-present:

=__Atomic Models:__= The solid Model proposed by Democritus and dalton Plum pudding Model proposed by Thomson This is the solid centered model that was accepted as the definite model until the introduction of the Uncrtainty Principle. The modern day variation of the atomic model is the same as the planetary model except for the fact that at any given time you cannot know the exact location of the electron. Because of this the model is diplayed as solid nucleus siting in an electroncloud.

Leucippus (Around 500-400 BC)
Leucippus was the teacher of Democritus. Born in the early 400's BC, not much is known about him or his work. What is known is that he founded the ideas of atomism. Democritus later expanded on the ideas Leucippus had introduced to him. He stated the theory that without vacuum(non-being), there could be no motion, yet at the same time he concluded that that state of non-being could not exist. several other philosophers reference the works of Leucippus, but few pieces of his own work remain. the closest thing we can find to his work is that of Democritus, who based most all of his work on what he learned from Leucippus.

[[image:89765~Democritus-circa-460-circa-370-BC-1692-Posters.jpg width="155" height="210"]]
Democritus was the student of Leucippus and shared many if not all of the theories his teacher had. Democritus believed that all matter was composed of small pieces or atoma, meaning indivisible unit. Democritus's reaserch was not limited to chemistry and like many of the philosophers of the time he studied astronomy and mathematics. He even went so far as to propose the posability of life on other planets. like Leucippus, he believed in the void/vacuum theory pertaining to the way atoms interacted. the only difference in their theories was that in Democritus's theory the void consisted of absolutely nothing. he believed that atoms were solid and the area around them was empty.

Aristotle (384-322)
Aristotle was a philosopher with wide spread interests. He wrote on everything from physics to politics to zoology. He theorized the presence of five elements that made up the universe. These five elements were fire, earth, air, water and aether. fire and earth made up the dry elements, air and water were the wet elements and aether was a devine element that made up heavanly bodies, such as stars and the moon. He agreed on a few subjects with Democritus and Leucippus, but for the most part he had his own theories. Other than these beliefs he focused mostly on the physics of how the world worked.

John Dalton (1766-1844)
John Dalton was a chemist and all around scholarly person. He did his chemical reaserch on the atom using gases, inaccurate measuring tools and lots of mathematics. He is most famous for his work on the atomic theory. He developed several laws concerning the way atoms combine and interact with each other. his stated laws are: Elements are made of atoms, atoms of an element are exactly the same, atoms of one element are different from those of any other element, atoms of different elements can combine to make compounds and atoms cannot be divided or destroyed or created by means of chemical reactions. John Dalton believed that atoms were solid and had some way of linking together individually with other atoms, rather than simply existing in mass quantity together as Democritus had thought.

William Crookes(1832-1909)
William Crookes was famous for his reaserch with the crooks tube and his discovery of the electron as a particle. The crooks tube was a glass vacuum tube that had an anode at one end and a cathode at the other. when an electrical charge passed through the tube from the cathode to the anode, the side of the tube opposite the cathode would glow. when the tube was filled with non-reactive gases such as neon or argon, a beam would become visible and the gas too would glow. it was later determined by way of confusing mathematics and reaserch that the beam consisted of electrons which are part of the body of the atom and the tube gave off x-ray radiation. along with this reaserch he made several contributions to the field of science.

Wilhelm C. Roentgen (1845-1923)
Roentgen is mainly credited with the discovery of x-rays and there effect on matter. By useing what was esentaily a crooks tube and a high voltage power supply, he could produce a form of radiation that is now known as x-ray radiation. when absorbant films were used the imprint of the x-rays and anything that got in their way (flesh,metal,ect.) would be left vissable on the film. His discovery of this new radiation would leed him to write several papers on the subject, yet he refused to assosiate his name with his discovery for fear that his findings would be disproved and that he would be mocked. Roentgen was awarded the first ever Nobel Prize in Physics in 1901.

Henri Becquerel (1852-1908)
Henri Becquerel was a major player in the field of radiation. in fact he was the scientist responsable for its discovery in 1896. while prepareing a sample on uranium salts, he bundled the photography platers in with the sample, in a sock drawer. up to tha point it was beleived that uranium among a few other elements would only flourece when exposed to light. As we now know from his findings, this is wrong. When he wemt to retrieve the platers and sample, Becquerel discovered that his platers had some how been exposed. The only sensible conclusion was the uranium in the drawer with the platers, but there was no source of light. Becquerel later dicovered that uranium gave off a faint glow even when no light was available. This led him to discover radiation which he found to be emited from all materials that would later be defined as radioactive by Marie curie amd her husband. based on these discoveries it was found that Roentgen's X-Rays were also a form of radiation emited by the cathode in the form of a ray. Henri Becquerel won half of the Nobel prize in physics in 1903 for his discoveries. The other half was split between Pierre and Marie Curie.

J.J. Thomson (1856-1940)
Thomson took an early interest in chemistry, and did a lot of exparamenting as a young adult. Later in his life he devised three different exparaments, each one tested a theory that was either accepted as true or he had devised. in the first exparament Thomson atemptted to seperate the negative charge of the electrons from the cathode rays. When he used a magnetic field to try and pull the rays away from the electrons, the rays still had a charge. as a result of this exparament, he found that cathode rays are inseperable from the electron beam. His second exparament was designed to test the theory that the cathode rays could not be deflected by an electric field(a property of charged particles). To test this he built a new tube and made an almost perfect vacuum, to fix a flaw he believed to be part of otherr scientists exparament. during the exparament Thomson concluded that the cathode rays did infact bend by way of the electric field. His third exparament of this set was designed to test the carge to mass ratio in the cathode rays he concluded from this exparament that the carge to mass ratio was 1000 times greater than that of a proton. There were two posible conclusions that could be made from this: either the partical that made up cathode rays, which he named corpuscles, were very small or they had an enormous charge. he also theorized hi plum pudding model of the atom based on the results from this exparament. For all hi work he was awarded the 1906 nobel prize in physics.

Marie Curie (1867-1934) and Pierre Curie (1859-1906)
Marie Skłodowska Curie, born Marie Skłodowska, married Pierre Curie a fellow chemist in 1995. Marie schooled in Paris, was a chemist in the field of radiation study. In Paris, she focused physics, mathematics and chemistry. For her time it was very unusual for a female to study such subjects, it was even more odd durring that time for her to be working in a lab. She and her husband Pierre owned a small warehouse, un-suitable for the work they were doing, yet it didnt stop them. Pierre's work up until the 1890's was primarily focused on the effects of electricity and magnatism on varios materials under certain conditions. He did a lot of his early reasherch on the topics of [|ferromagnatism], [|paramagnatism], and [|diamagnatism]. During exparamentation, Pierre and his older brother discovered the piezoelectric effect on crystals, an effect that is thouroughly exploited in modern atomic clocks that rely on the crystals occilation to be exactly 60 hertz. After getting maried to Marie he shifted hi focus to teaching and helping Marie with her reaserch. The both of them later were credited with the discovery of polonium and radium, which they had painstakenly isolated by hand from several tons of pitchblend. despite the low yield of these two elements, Marie and Pierre's work led to break-through reaserch on what they called radioactivity. For their hard work they were jointly awared half of the 1903 nobel prize. The other half went to Becquerel, who's work had inspired them to do their own. Pierre later, while working with one of his students, made the first discovery of nuclear energy. This nuclear energy was identified by the constant relese of heat from a radium sample. from this particular peice of work Pierre also identifide alpha, beta, and gamma radiation emission. Pierre, was later killed in a street accident in 1906, when a cariage roled over his head. Marie Curie went on to win the nobel prize in chemistry in 1911 for her discovery of radium and the isolation method. She continued to do reasech with radium, focused on medical and theriputical work, which the USA suported with funding for her Warsaw Radium Institute, which she founded in 1925. she later died in 1934, from what is suspected to be prolonged radiation exposure. In 1935 her doughter, Irène Joliot-Curie, won the nobel prize in chemistry for her work on making aluminium radioactive among other things.

Robert Millikan (1868-1953)
Robert Millikan was responsable for finding the exact charge of the electron. To do this he used his falling drop method in which he used oil and two elecromagnetic plates. The first plate gave the oil drops a small charge, the oil then fell towards the second plate which had a negative charge, same as the oil so as to repel the oil. He could tune his set up so precisly that he could ge the oil drops to be suspended in mid-air, repeled be the electromagnetic feild of the second plate. Most of his reaserch was done on atomic physics and the photoelectric effect. It was his work this particular feild of reasech that got him the 1923 nobel prize in physics. The photoelectric effect is essentaily the anomaly that occurs when materials absorb mass amounts of high frequncy electromagnetic waves, such as X-rays and gamma rays. The effect of this is the release of the electrons belonging to the atoms of the target meterial. Work in this field led to the theorization of the wave-partical duality that applies to the way electrons and photons interact with other particals. Millikan, believing firmly in a good education, dedicated much of his later life to working in the California Institute of Technology.

Ernest Rutherford (1871-1937)
Ernest Rutherford, famous for his gold foil exparament, actualy focused mostly on topics other than the atomic structure. His work varried from working on the atomic model to catagorizing forms of radiation; he even worked on developing laws that described the properties of radioactive decay. His most famous exparament was the gold foil exparament involved a lead box containing a source of alpha partical radiation, which he fired into an inclosure. Inside this enclosure was a peice of gold foil which had been heated and hammered to a thickness of about 200 atoms, the inside walls of the enclosure was coated in reactive materials that signafied the impact of the alpha particles. After shooting the radiation strait at the foil, Rutherford was suprised to find that some (around 1:8000) of the alpha particals had been deflected by something solid in the foil. If Thomson's Plum puding theory had held true, the alpha particals would have passed striat through the foil and the only exposed area of the coating would be directly oposte the entry point of the radiation into enclousure. Instead, there were marks from exporure primarily in the expected area, but also at diferent trajectories such as striat back at the soure and off a different angles. This led Rutherford with the help of one of his students to the theory that the atom had a solid center with the electrons in orbit around the nucleus, in what was called the orbital model. In 1908 he won th nobel prize in chemistry for his work on radeoactive decay. In several exparaments, Rutherford demonstrated that the state of radioactivity was defined by the continuos and spontainios disintigration of the atom. He also developed ways of calculating the "half life" (the time it takes the atom to exponentialy decay to half of its origionaly measured radeoactive value) of atoms, including ways to use it to calculate the age of the earth, and now even things like how long someone has been dead. During exparaments in his later life he was able to rip apart nitrogen atoms and make them into oxygen atoms. This was the first recorded example of the intentional spliting of atoms. From the collection of all of his exparamens he theorized the Rutherford Model, an atomic model with a very small positivly nucleus and free floating electrons whose charges were equal yet oposite, so as to cancel each other out. He had at this point, theorized the existance of the neutrons, which would have made up for the unacounted for mass of the atom. The official discovery was left to James Chadwick in 1932.

Neils Bohr (1885-1962)
Neils Bohr developed the first model of the atom, in which the electrons had a set path. He had come this conclusion from studieing under Ernest Rutherford and faithfuly sharing the same ideas as his teacher. Bohr believed strongly that the electrons had set orbits though, which set his model apart from the others. He even went so far as to say that the chemical properties of atoms were based partaily on the placement of the electrons. After some amount of exparamenting Bohr also discovered that electrons could drop from a high orbit to a lower one, in which case the atom would relaese a photon of a certain color (frequncy) depending on how far and from where the electron droped. This particular aspect of his work on the atomic model played a big role in the founding of quantum mechanics. For this work he was awarded with the 1922 nobel prize in physics. But his list of acomplishments didnt end there. He was a professor at the University of Copenhagen, where he tought physics to young minds such as Werner Heisenberg. Heisenberg also became a major player in the development of quantom mechanics and the creation of the modern atomic model. Heisenberg and Bohr also colaberated as equals on the topic of the Copenhagen Interpretation, in which they attept to explain some problems with the quantum theory of the time. During WWII Bohr escaped to Sweden and later to London, where he helped in the Manhatten project in an attempt to beat Germany in the developement of the first nuclear wepons.

Erwin Schrödinger (1887-1961)
Erwin Schrödinger was a famous theoretical physisist who played a large role in the developement of quantum mechanics. He was influenced at an early age by Fritz Hasenöhrl, and eventualy developed a skill with the mathematics of the Quantum theories. By 1926 Schrödinger had created the Schrödinger Wave Equation, a partial differential equation that describes the evolution/change of the wavefunction over time. His understanding of the mathematics of the quantum theory led him to devise equations for everything he could. He created one equation in particular, that replaced Bohr's theory on how photons were generated by electrons in atoms with a more mathematical method. This led to his winning half of the 1933 nobel prize for physics. Schrödinger really was the king of quantum math and the laws that his math aplied to. In his later life, Schrödinger wrote on the posibility of a complex moecule that migh contian the instructions for the human body. It was only a theory then, now we call it DNA.

James Chadwick is primarily famous for his discovery of the neutron in 1932. This was a big deal because up until then nearly half the atomic mass of any given atom was un acounted for, Chawick essentaily discovered half the atom. The discovery of neutrons allowed for much simpler methods for spliting the atom. The mearly needed to bombard the atom with neutrons until it became unstable and ripped itself apart. Previos methods had involved the use of alpha particals which have an electrical charge and were repeled by larger atoms, such as gold, let alone uranium. Chadwick was awarded the 1935 nobel prize in physics for his discovery of the neutron and a method of effectivly splitting atoms. At one point Chadwick offered to share the prize with Hans Falkenhagen, a german scientist who had also discovered the neutron at the same time as Chadwick. Hans Falkenhagen denied the offer, leaving all credit for Chadwick. Because of Chadwicks work Fritz Strassmann and Otto Hahn, two german radeochemists, were able to discover nuclear fission. Chawick later joined the Manhatten Project durring WWII.

Werner Heisenberg (1901-1976)
Werner Heisenberg was one of the major founders of quantum mechanics, along with his teacher and lond time friend, Neils Bohr. Durring his work in the 1920-30's, Heisenberg developed his uncertainty principle. This principle basicaly said that at any given time you could never know exactly where an electron was because of a few things. First of because electrons acted as both waves and particals, secondly electrons are easily influenced (the process of locating one throws off the results of where it really is), and thirdly electrons can move, for the most part, pretty freely within the set orbital paths. As a result of these factors you can only theorize a list of probable locations as to where the electron might be. This is what the Uncertainty principle also helps you do. In 1932 he was awarded the nobel prize in physics for his contributions and co-founding of Quantu mechanics. During WWII, Heisenberg stayed with Nazi Germany to re-build the scientific comunity and to help in the nuclear project going on at the time in Germay.

==Bibliography: http://www.corrosion-doctors.org/Biographies/MillikanBio.htm http://www.wikipedia.org/ http://www.jergym.hiedu.cz/~canovm/osobnost/emenu.htm [|http://nobelprize.org] http://www.fordhamprep.org/gcurran/sho/sho/lessons/lesson32.htm==