Fall.2010.MMA.Neil.atomictimeline

ATOMIC HISTORY TIMELINE PROJECT﻿ By: Michael Neil

//﻿ Timeline: // Ancient Times
 * Empedocles (490-430 B.C.)[[image:http://www.nndb.com/people/832/000087571/empedocles-2-sized.jpg width="236" height="234" align="right"]]**

He was born at Acragas in Sicily around 492 BC and died at the age of sixty. He was the son of a certain Meton, and was from an important and wealthy local aristocratic family. The foundations of Empedocles’ physics lie in the assumption that there are four ‘elements’ of matter, or ‘roots’ as he calls them, using a botanical metaphor that stresses their creative potential: earth, air, fire and water. These are able to create all things, including all living creatures, by being ‘mixed’ in different combinations and proportions. Each of the elements however, retains its own characteristics in the mixture, and each is eternal and unchanging. [], (picture) []

Democritus was born at Abdera, about 460 BCE. His father was from a noble family and of great wealth. He maintained the impossibility of dividing things. From the difficulty of assigning a beginning of time, he argued the eternity of existing nature, of void space, and of motion. He was a Greek philosopher who developed the concept of the 'atom', Greek for 'indivisible'. Democritus believed that everything in the universe was made up of atoms, which were microscopic and indestructible. [], (picture) []
 * [[image:http://www.desy.de/f/hera/fig/general/Democritus.jpg width="178" height="236" align="left"]]Democritus (460 - 370 B.C.)**

Aristotle was born in 384 BCE at Stagirus. At age 17 his guardian, Proxenus, sent him to Athens, the intellectual center of the world, to complete his education. He joined the Academy and studied under Plato, attending his lectures for a period of twenty years. He emphasized that nature consisted of four elements: air, earth, fire, and water. He thought these are bearers of fundamental properties, dryness and heat being associated with fire, heat and moisture with air, moisture and cold with water, and cold and dryness with earth. He did not believe in discontinuous or separate atoms but felt that matter was continuous. Aristotle introduced the fifth element that he said all heavenly bodies (Sun, moon, and stars, etc.) were made of. He also said the fifth element could turn cheap metals into gold and cure disease and old age. [], [], (picture) http://mrsvesseymathematicians.wikispaces.com/Aristotle
 * Aristotle (384 - 322 B.C.)**

450-1700 **Pierre Gassendi (1592 – 1655)** The core of Gassendi's mature philosophy and natural philosophy is his atomist matter theory.The broadest atomist claims Gassendi makes are rooted in his background metaphysics and rejection of the infinite divisibility of matter. He grounds the finer points of his atomism—regarding the qualities of atoms and their aggregates—on observations, experiment, and interpretations of the same, as well as his assessments of alternative perspectives on matter theory. To establish that atoms are the primary principles or elements of matter, Gassendi draws deeply on the well of ancient atomist argument. [], (picture) [] qqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqq qqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqq qqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqq qqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqq

**Robert Boyle (1627-1691)** He was born at Lismore Castle, Munster, Ireland. Through his early years he was tutored at home. At the time of the restoration of the British monarchy in 1660, Boyle played a key role in founding the Royal Society to nurture this new view of science. Although Boyle’s chief scientific interest was chemistry, his first published scientific work, //New Experiments Physico-Mechanicall, Touching the Spring of the Air and Its Effects// (1660), concerned the physical nature of air, as displayed in a brilliant series of experiments in which he used an air pump to create a vacuum. The second edition of this work, published in 1662, delineated the quantitative relationship that Boyle derived from experimental values, later known as “Boyle’s law”: that the volume of a gas varies inversely with pressure. [], (picture) Born at Woolsthorpe, near Grantham in Lincolnshire, where he attended school, he entered Cambridge University in 1661. He found white light to be a mixture of infinitely varied coloured rays (manifest in the rainbow and the spectrum), each ray definable by the angle through which it is refracted on entering or leaving a given transparent medium. He correlated this notion with his study of the interference colours of thin films (for example, of oil on water, or soap bubbles), using a simple technique of extreme acuity to measure the thickness of such films. He held that light consisted of streams of minute particles. He sought understanding of the nature and structure of all matter, formed from the "solid, massy, hard, impenetrable, movable particles" that he believed God had created. Also, in his work, Newton described universal gravitation and the three laws of motion. [], (picture) []
 * Sir Isaac Newton (1642-1727)**

﻿ 1700-1800 Also known as the "Father of Modern Chemistry." Antoine ﻿Laurent Lavoisier was born on the Augest 26, 1743. He was the son of Jean-Antoine Lavoisier, a prominent advocate, and his wife and Emilie Punctis, the daughter of an advocate of the Parliament. Emilie died three years after the birth of his little sister Marie. Antoine was 5 years old at the time. Lavoisier proved that oxygen played the major role in the differences in weight associated with combustion, disproving the accepted view of the Phlogiston Theory. He proved the Law of Conservation of Mass, showing that the mass of the reactants had to equal the mass of the products. Lavoisier and a small group of other scientists created the Method of Chemical Nomenclature in which they classified the distinctions between elements. Lavoisier also clarrified the distinction between elements and compounds. [], [], (picture) []
 * Antoine Lavoisier (1743-1794)[[image:http://www.homeoint.org/morrell/articles/photo/lavoisier.jpg width="201" height="195" align="right"]]**

Henry Cavendish was born on October 10, 1731 in Nice, France, where his family was living at the time. His mother was Lady Anne Gray, daughter of the Duke of Kent and his father was Lord Charles Cavendish, son of the second Duke of Devonshire. The family traces its lineage across eight centuries to Norman times and was closely connected to many aristocratic families of Great Britain. Cavendish attended Cambridge University from 1749 to 1753, but left without a degree. He was a British scientist noted for his discovery of hydrogen or what he called "inflammable air." He also described the composition of water and made the first accurate measurement of the density of the Earth. [], [], (picture) []
 * [[image:http://www.nndb.com/people/030/000083778/henry-cavendish-1.jpg width="131" height="164" align="left"]]Henry Cavendish (1731-1810)**

Amedeo Avogadro was born August 9, 1776 and died July 9, 1856. He was born and died in Turin, Italy. Amedeo Avodagro, conte di Quaregna e Ceretto, was born into a family of distinguished lawyers. Following in his family's footsteps, he graduated in ecclesiastical law at the age of 20 and began to practice law. Avogadro's law states that equal volumes of gases, at the same temperature and pressure, contain the same number of molecules. Avogadro's hypothesis wasn't generally accepted until after 1858 (after Avogadro's death). Avogadro believed that particles could be composed of molecules and that molecules could be composed of still simpler units, atoms.The number of molecules in a mole (one gram molecular weight) was termed Avogadro's number (sometimes called Avogadro's constant) in honor of Avogadro's theories. Avogadro's number has been experimentally determined to be 6.023x1023 molecules per gram-mole. [], (picture) []
 * Amedeo Avogadro (1776-1856)[[image:http://static.newworldencyclopedia.org/3/3c/Amedeo_Avogadro2.jpg width="118" height="174" align="right"]]**

1800-1875 He was born into a modest Quaker family in Cumberland, England, and earned his living for most of his life as a teacher and public lecturer, beginning in his village school at the age of 12. After teaching 10 years at a Quaker boarding school in Kendal, he moved on to a teaching position in the burgeoning city of Manchester. His atomic theory, stated that elements consisted of tiny particles called atoms. He said that the reason an element is pure is because all atoms of an element were identical and that in particular they had the same mass. He also said that the reason elements differed from one another was that atoms of each element were different from one another; in particular, they had different masses. He also said that compounds consisted of atoms of different elements combined together. Compounds are pure substances (remember they cannot be separated into elements by phase changes) because the atoms of different elements are bonded to one another somehow, perhaps by hooks, and are not easily separated from one another. Compounds have constant composition because they contain a fixed ratio of atoms and each atom has its own characteristic weight, thus fixing the weight ratio of one element to the other. In addition he said that chemical reactions involved the rearrangement of combinations of those atoms. He proceeded to calculate atomic weights from percentage compositions of compounds, using an arbitrary system to determine the likely atomic structure of each compound. [], [], (picture) []
 * [[image:http://atomicideas.pbworks.com/f/dalton.gif width="144" height="191" align="left"]]**
 * John Dalton (1766-1844)**

[], (picture) []
 * [[image:http://www.chem.shef.ac.uk/chm131-2002/cha02ts/henri_bacquerel.jpg width="177" height="207" align="right"]]Henri Becquerel (1852-1908)**He was born in Paris on December 15, 1852, a member of a distinguished family of scholars and scientists. His father, Alexander Edmond Becquerel, was a Professor of Applied Physics and had done research on solar radiation and on phosphorescence, while his grandfather, Antoine César, had been a Fellow of the Royal Society and the inventor of an electrolytic method for extracting metals from their ores. Becquerel's earliest work was concerned with the plane polarization of light, with the phenomenon of phosphorescence and with the absorption of light by crystals (his doctorate thesis). Becquerel showed that the rays emitted by uranium, which for a long time were named after their discoverer, caused gases to ionize and that they differed from X-rays in that they could be deflected by electric or magnetic fields.

He was born on March 27, 1845, at Lennep in the Lower Rhine Province of Germany, as the only child of a merchant in, and manufacturer of, cloth. He then entered the University of Utrecht in 1865 to study physics. Not having attained the credentials required for a regular student, and hearing that he could enter the Polytechnic at Zurich by passing its examination, he passed this and began studies there as a student of mechanical engineering. Rontgen's first work was published in 1870, dealing with the specific heats of gases, followed a few years later by a paper on the thermal conductivity of crystals. Rontgen's name, however, is chiefly associated with his discovery of the rays that he called X-rays. In 1895 he was studying the phenomena accompanying the passage of an electric current through a gas of extremely low pressure. On the evening of November 8, 1895, he found that, if the discharge tube is enclosed in a sealed, thick black carton to exclude all light, and if he worked in a dark room, a paper plate covered on one side with barium platinocyanide placed in the path of the rays became fluorescent even when it was as far as two metres from the discharge tube. [], (picture) []
 * [[image:http://1.bp.blogspot.com/_GF_X5q0eY90/SkC1g84rrkI/AAAAAAAABMg/YXyy3TVvLi8/s400/Wilhelm_C_Roentgen_1.jpg width="211" height="246" align="left"]]Wilhelm C. Roentgen (1845-1923)**

1875-1900 She was born in Warsaw on November 7, 1867, the daughter of a secondary-school teacher. She received a general education in local schools and some scientific training from her father. Her early researches, together with her husband, were often performed under difficult conditions, laboratory arrangements were poor and both had to undertake much teaching to earn a livelihood. The discovery of radioactivity by Henri Becquerel in 1896 inspired the Curies in their brilliant researches and analyses which led to the isolation of polonium, named after the country of Marie's birth, and radium. Curie developed methods for the separation of radium from radioactive residues in sufficient quantities to allow for its characterization and the careful study of its properties, therapeutic properties in particular. [], (picture) http://www.chem.shef.ac.uk/chm131-2002/cha02ts/discovery_of_radiation.html
 * [[image:http://www.chem.shef.ac.uk/chm131-2002/cha02ts/marie_and_pierre_curie.jpg width="177" height="174" align="right"]]Marie Curie (1867-1934)**

He was born on August 30, 1871, in Nelson, New Zealand, the fourth child and second son in a family of seven sons and five daughters. His father James Rutherford, a Scottish wheelwright, emigrated to New Zealand with Ernest's grandfather and the whole family in 1842. His mother, //née// Martha Thompson, was an English schoolteacher, who, with her widowed mother, also went to live there in 1855. Rutherford's first researches, in New Zealand, were concerned with the magnetic properties of iron exposed to high-frequency oscillations. In 1898 he reported the existence of alpha and beta rays in uranium radiation and indicated some of their properties. At Manchester, Rutherford continued his research on the properties of the radium emanation and of the alpha rays and, in conjunction with H. Geiger, a method of detecting a single alpha particle and counting the number emitted from radium was devised. In 1910, his investigations into the scattering of alpha rays and the nature of the inner structure of the atom which caused such scattering led to the postulation of his concept of the "nucleus", his greatest contribution to physics. According to him practically the whole mass of the atom and at the same time all positive charge of the atom is concentrated in a minute space at the center. [], (picture) []
 * [[image:http://schools-wikipedia.org/images/72/7239.jpg width="225" height="281" align="left"]]Ernest Rutherford (1871-1937)**

He was born on the 22nd of March, 1868, in Morrison, Ill. (U.S.A.), as the second son of the Reverend Silas Franklin Millikan and Mary Jane Andrews. His grandparents were of the Old New England stock which had come to America before 1750, and were pioneer settlers in the Middle West. He led a rural existence in childhood, attending the Maquoketa High School (Iowa). His earliest major success was the accurate determination of the charge carried by an electron, using the elegant "falling-drop method"; he also proved that this quantity was a constant for all electrons (1910), thus demonstrating the atomic structure of electricity. The discovery of his law of motion of a particle falling towards the earth after entering the earth's atmosphere, together with his other investigations on electrical phenomena, ultimately led him to his significant studies of cosmic radiation (particularly with ionization chambers). [], (picture) []
 * Robert Milikan (1868 - 1953)[[image:http://www.newfield.cl/newsletter/images_news/millikan.jpg width="160" height="191" align="right"]] **

1900-1915 He was born in Cheetham Hill, a suburb of Manchester on December 18, 1856. Thomson returned to America in 1904 to deliver six lectures on electricity and matter at Yale University. They contained some important suggestions as to the structure of the atom. He discovered a method for separating different kinds of atoms and molecules by the use of positive rays. He discovered the electron in a series of experiments designed to study the nature of electric discharge in a high-vacuum cathode-ray tube, an area being investigated by numerous scientists at the time. [], [], (picture) []
 * [[image:http://www.manep.ch/img/photo/challenges/nanotubes/thompson.jpg width="359" height="229" align="left"]]JJ Thomson (1856-1940) **

He was born in Copenhagen on October 7, 1885, as the son of Christian Bohr, Professor of Physiology at Copenhagen University, and his wife Ellen, //née// Adler. Niels, together with his younger brother Harald (the future Professor in Mathematics). he succeeded in working out and presenting a picture of atomic structure that, with later improvements (mainly as a result of Heisenberg's ideas in 1925), still fitly serves as an elucidation of the physical and chemical properties of the elements. A liquid drop would, according to this view, give a very good picture of the nucleus. This so-called //liquid droplet theory// permitted the understanding of the mechanism of nuclear fission. He said that electrons existed at set levels of energy, that is, at fixed distances from the nucleus. If the atom absorbed energy, the electron jumped to a level further from the nucleus; if it radiated energy, it fell to a level closer to the nucleus. [], [], (picture) []
 * Neils Bohr (1885-1962)[[image:http://www.freeinfosociety.com/media/images/1186.jpg width="167" height="198" align="right"]] **

He was born on August 12, 1887, in Vienna, the only child of Rudolf Schrodinger, who was married to a daughter of Alexander Bauer, his Professor of Chemistry at the Technical College of Vienna. With Hitler's coming to power (1933), however, Schrödinger decided he could not continue in Germany. He came to England and for a while held a fellowship at Oxford. He began explaining the movement of an electron in an atom as a wave. By 1926 he published his work, providing a theoretical basis for the atomic model that Niels Bohr had proposed based on laboratory evidence. The equation at the heart of his publication became known as Schrodinger's wave equation. [], [], (picture) []
 * [[image:http://scienceblogs.com/builtonfacts/2008/09/28/sch width="129" height="176" align="left"]]Erwin Schrodinger (1887-1961)**

1915-1950 He was born in Cheshire, England, on 20th October, 1891, the son of John Joseph Chadwick and Anne Mary Knowles. In 1932, Chadwick made a fundamental discovery in the domain of nuclear science: he proved the existence of //neutrons// - elementary particles devoid of any electrical charge. In contrast with the helium nuclei (alpha rays) which are charged, and therefore repelled by the considerable electrical forces present in the nuclei of heavy atoms, this new tool in atomic disintegration need not overcome any electric barrier and is capable of penetrating and splitting the nuclei of even the heaviest elements. Chadwick in this way prepared the way towards the fission of uranium 235 and towards the creation of the atomic bomb. James Chadwick proved the existence of neutrons, the elementary particle without any electrical charge and a fundamental building block of the atom's nucleus. During World War II he came to America, where he contributed to the Manhattan Project that developed the world's first atomic weapons. [], [], (picture) []
 * James Chadwick (1891-1974)[[image:http://www.nndb.com/people/728/000099431/james-chadwick-1-sized.jpg width="169" height="237" align="right"]]**

He was born on 5th December, 1901, at Würzburg. He was the son of Dr. August Heisenberg and his wife Annie Wecklein. His father later became Professor of the Middle and Modern Greek languages in the University of Munich. At the end of the Second World War he, and other German physicists, were taken prisoner by American troops and sent to England, but in 1946 he returned to Germany and reorganized, with his colleagues, the Institute for Physics at Göttingen. This Institute was, in 1948, renamed the Max Planck Institute for Physics.Heisenberg's name will always be associated with his theory of quantum mechanics, published in 1925. Later Heisenberg stated his famous //principle of uncertainty//, which lays it down that the determination of the position and momentum of a mobile particle necessarily contains errors the product of which cannot be less than the quantum constant //h// and that, although these errors are negligible on the human scale, they cannot be ignored in studies of the atom. In 1932 he explained the principle of isotopic spin (isospin), a quantum number which arises from regarding different members of a charge multiplet as different states of a single particle. During World War II he led Germany's failed efforts to develop an atomic bomb. [], [], (picture) []
 * [[image:http://www.edge.org/3rd_culture/heisenberg07/images/Lecture-pic.jpg width="359" height="350" align="left"]]Werner Heisenberg (1901-1976)**

A British chemist, Henry Moseley studied under Rutherford and brilliantly developed the application of X-ray spectra to study atomic structure; Moseley's discoveries resulted in a more accurate positioning of elements in the Periodic Table by closer determination of atomic numbers. Henry Moseley published the results of his measurements of the wavelengths of the X-ray spectral lines of a number of elements which showed that the ordering of the wavelengths of the X-ray emissions of the elements coincided with the ordering of the elements by atomic number. With the discovery of isotopes of the elements, it became apparent that atomic weight was not the significant player in the periodic law as Mendeleev, Meyers and others had proposed, but rather, the properties of the elements varied periodically with atomic number. When atoms were arranged according to increasing atomic number, the few problems with Mendeleev's periodic table had disappeared. Because of Moseley's work, the modern periodic table is based on the atomic numbers of the elements. [], [], (picture) []
 * Henry Moseley (1887-1915)[[image:http://scienceworld.wolfram.com/biography/pics/Moseley.jpg width="136" height="219" align="right"]]**

//**Models:**// Small, Spherical, Solid, Indivisible Model Democritus postulated the existence of invisible atoms, characterized only by quantitative properties: size, shape, and motion. Imagine these atoms asindivisible spheres, the smallest pieces of an element that still behave like the entire chunk of matter. []

 Electron Cloud Model The electron cloud model is an atom model wherein electrons are no longer depicted as particles moving around the nucleus in a fixed orbit. Instead, as a quantum mechanically-influenced model, we shouldn’t know exactly where they are. []

 Plum Pudding Model In Thomson’s "Plum Pudding Model" each atom was a sphere filled with a positively charged fluid. The fluid was called the "pudding." Scattered in this fluid were electrons known as the "plums." Thomson suggested that the positive fluid held the negative charges, the electrons, in the atom because of electrical forces. []

<span style="display: block; font-family: 'Times New Roman',Times,serif; font-size: 180%; text-align: center;"> Rutherford-Bohr Model The modern model of the atom is based on quantum mechanics.The Bohr Model is a planetary model in which the negatively-charged electrons orbit a small, positively-charged nucleus. Electrons orbit the nucleus in orbits that have a set size and energy. [] <span style="display: block; font-family: 'Times New Roman',Times,serif; font-size: 180%; text-align: center;">

Planetary Model Very similar to the Rutherford-Bohr Model concept. James Chadwick further discovered the atom. Chadwick discovered a previously unknown particle neutron in the atomic nucleus. []