422-004+S.+Lombardi+&amp;+B.+Feak+BigTimeLine+Project

__**History of the Atom**__


 * -[|600 BCE]: Rome -** The Etruscans, believed to be natives of Asia Minor, establish cities stretching from northern to central Italy. Their major contributions to the Romans are the arch and the vault, gladiatorial combat for entertainment and the study of animals to predict future events. The Greeks establish city-states along the southern coast of Italy and the island of Sicily. Their contributions to the Romans are the basis of the Roman alphabet, many religious concepts and artistic talent as well as mythology.


 * -[|509 BCE]: Rome -** The Roman monarchy is overthrown and replaced with a republic. For more than two centuries following the establishment of the Roman Republic, Rome is constantly at war with the other inhabitants of Italy (the Etruscans and the Greeks).

__//-Leucippus// **500-450** **BC**. //Greek//__ Leucippus was one of the very first known philosophers and physicist he was most influenced by the teachings of Zeno of Elea. He is credited with the invention of atomism. But because his teaching have been folded over in his student, Democritus and his writings it is in-distinguishable to identify what views in which they disagreed upon. He is considered the originator of the theory that of which,[ the universe consists of two different elements, which where called, ‘the full’ or ‘solid’ and ‘the empty’ or ‘void’, both of which are thought to be infinite, and between them constitutes the elements of everything]. //_ __Democritus **470-370** **BC**__// __Greek__ Democritus, student of Leucippus, who systematized his views on the atom, and expanded the atomic theories of Leucippus’ as well. He is considered co- originator of atomism. He believed all matter is made up of various imperishable, indivisible elements “Atoma” = indivisible unit. He also argued the eternity of existing nature, void space, and of motion. _ __//Aristotle **384-322** **BC**// Greek__ Aristotle: mostly a psych philosopher. He to believed everything was made up of elements, but that they could be changed, molded into different matter. He also thought up the first scientific method relating to perspective; logic to reason out, of gaining the knowledge of and object, which include ‘substance, quantity, quality, relation, place, time, situation, condition, action, and passion.


 * -[|264 BCE]: Rome -** Rome initiates the Punic Wars with Carthage, an oligarchic empire stretching from the northern coast of Africa to the Strait of Gibraltar. The primary cause of these Wars is Carthaginian expansion into the Greek cities of Sicily. Carthage is forced to surrender its control over the western region of Sicily, which marks the end of the First Punic War.

The Enlightenment was the product of a vast set of cultural and intellectual changes in Europe during the 1500s and 1600s—changes that in turn produced the social values that permitted the Enlightenment to sweep through Europe in the late 1600s and 1700s. One of the most important of these changes was the Scientific Revolution of the 1500s and 1600s. During the Scientific Revolution, European thinkers tore down the flawed set of “scientific” beliefs established by the ancients and maintained by the Church. To replace this flawed knowledge, scientists sought to discover and convey the true laws governing the phenomena they observed in nature.
 * -1700's The Enlightenment**

__//-Joseph Priestley **1733-1804**// English__ Joseph Priestly – was best remembered for the discovery of oxygen, proving the air itself was not an element. He was mostly known for his political philosophies.


 * -1745-,** confrontation that led to the French conquest of Flanders during the //**__War of the Austrian Succession__**//. It was the most famous victory of the French marshal Maurice, Count de Saxe[|**.**] The battle was fought 5 miles (8 km) southeast of Tournai (in modern Belgium), between 52,000 French troops under de Saxe and about 50,000 Allied troops (composed of English, Hanoverian, Dutch, and Austrian units) …
 * -1755-**The //**__French and Indian War__**//, as it was referred to in the colonies, was the beginning of open hostilities between the colonies and Gr. Britain. England and France had been building toward a conflict in America since 1689. These efforts resulted in the remarkable growth of the colonies from a population of 250,000 in 1700, to 1.25 million in 1750. Britain required raw materials including copper, hemp, tar, and turpentine. They also required a great deal of money, and so they provided that all of these American products be shipped exclusively to England (the Navigation Acts). In an effort to raise revenue and simultaneously interfere with the French in the Caribbean, a 6 pence tax on each gallon of molasses was imposed in 1733 (the Molasses Act: The Sugar Act). Enforcement of these regulations became difficult, so the English government established extensive customs services, and vice-admiralty courts empowered to identify, try, and convict suspected smugglers. These devices were exclusive of, and superior to, the colonial mechanisms of justice.

The Declaration is considered to be a preceding founding document of the later formed United States of America, where July 4 is celebrated as Idependence Day. At the time the Declaration was issued, the American colonies were "united" in declaring their independence from Great Britain. The Industrial Revolution was a period in the late 18th and early 19th centuries when major changes in agriculture, manufacturing, and transportation had a profound effect on socioeconomic and cultural conditions in Britian and subsequently spread throughout the world, a process that continues as industrialisation. The onset of the Industrial Revolution marked a major turning point in human social history, comparable to the invention of farming or the rise of the first city-states; almost every aspect of daily life and human society was eventually influenced in some way.
 * //-United States Declaration of Independence Signed (1776)//**
 * //-//Industrial Revolution (1800’s)**

__//-Sir Humphry Davy **1778-1829**.// English__ Sir Humphry Davy- studied the medical value of various gasses. He was a superintendent of the Medical Pneumatic Institution of Bristol. There he studied oxides of Nitrogen and discovered the physiological effects of Nitrous Oxide “Laughing Gas”, later to be used as an anesthetic. He later experimented with electrolysis and alkali metals and soon found out that when he passed electrical currents through some substances; these substances would decompose, a progress later known as electrolysis. He identified Chlorine and Iodine to be elements. _ __//John Dalton **1766-1844**// English__ John Dalton- Gave a foundation of the modernized atomic theory, included with theoretical and chemical proof and experiments.

1. All matter is made up of atoms. Atoms are indivisible and indestructible. 2. All atoms of a given element are identical in mass and properties. 3. Compounds are formed by a combination of two or more different kinds of atoms. 4. A chemical reaction is a rearrangement of atoms.

Texas was part of the Spanish colony of New Spain, they revolted and fought. The texian forces wonn and became part of the U.S. __//-Wilhelm Conrad Röntgen **1845-1923**// German__ 1895 – He was the first scientist to discover, observe, and record X-rays. He was fiddling with a set of cathode ray instruments and found a flickering image was cast. Later he observed a nearby piece of Barium Platinocynide gave off light when the cathode ray was operating. He then theorized that when the cathode- rays struck the glass wall of the tube, some unknown radiation was formed that traveled across the room, struck the chemical, and caused the fluorescence. Further investigation revealed that paper, wood, and aluminum, among other materials, are transparent to this new form of radiation. He found that it affected photographic plates, and, since it did not noticeably exhibit any properties of light, such as reflection or refraction, he mistakenly thought the rays were unrelated to light. In view of its uncertain nature, he called the phenomenon X-radiation, though it also became known as Röntgen radiation. He took the first X-ray photographs, of the interiors of metal objects and of the bones in his wife's hand.
 * The Alamo** (1836)

__//-Henri Becquerel **1852-1908**// French __ He worked with Potassium Uranyl Sulfate, which he exposed to sunlight, placed on photographic plates wrapped in black paper. When developed the plates revealed an image of uranium crystals. Initially he concluded the suns energy was being absorbed by the Uranium, which then emitted X-rays. On a rainy day he stuck the Uranium covered plates in a draw. He expected a faint image would appear but after developing the plates he was surprised to find clear and strong vivid images. Therefore he concluded that the uranium emitted radiation with out an external source of energy. With that he had discovered “radioactivity”- the spontaneous emission of radiation by a material.

__//-J. J. Thompson **1856-1940**// English__ J.J. studied cathode-rays and discovered electrons in 1897. He concluded that electrons were small negatively charged points in the atom. As an example he chose a plum pudding to refer to his atomic model. The model was then referred to as the plum -pudding model.


 * American Civil War** (1861-1865)- The American Civil War was a very chaotic era for the United States. It occured between the years of 1861-1865. The basis of this war was slavery, freedom, and natural rights. The North and South of the country were divided because the North was opposed to slavery and the South was for it. The North believed that all men should be created equal and the South believed they had a right to slavery. The Norths population immensely out numbered the Souths so they had an advantage. After many years of fighting, battles, and bloody warfare, the North over powered the South and won the war. The results were freedom nationally and the country fell into a period of reconstruction. And after a short relief period, the country was booming again, although we will never live it down that we once, at least partially, psupported slavery.

__//-Marie Curie **1867-1934**// Polish__ She and her husband Pierre Curie began investigating the phenomenon of radioactivity, recently, at that time, discovered in Uranium by Henri Becquerel, but the term radioactivity was coined by Marie. They extracted uranium from the ore, that in which they discovered to be more “active”. She concluded that the ore included, in addition to uranium, new elements that were also highly radioactive. This led to the discoveries of the elements of Polonium and Radium in 1898. But it took them approximately four more years to obtain enough isolated element to determine the chemical properties of each element. They both received Nobel prizes of physics, and after Pierre’s unfortunate death Marie Curie received the Nobel in chemistry, she was the first person t achieve that level of appreciation.

__//-Robert Millikan **1868-1953**// American__ Discovered the universal constat charge of the electron. The Oil-Drop Experiment Apparatus "The scheme of the experiment is as follows: An atomizer sprayed a fine mist of oil droplets into the upper chamber. Some of these tiny droplets fell through a hole in the upper floor. Millikan first let them fall until they reached terminal velocity due to air resistance. Using the microscope, he measured their terminal velocity, and by use of a formula, calculated the mass of each oil drop. Next, Millikan applied a charge to the falling drops by irradiating the bottom chamber with x-rays. This caused the air to become ionized, which basically means that the air particles lost electrons. A part of the oil droplets captured one or more of those extra electrons and became negatively charged. By attaching a battery to the plates he created an electric field between the plates that would act on the charged oil drops; he adjusted the voltage till the electric field force would just balance the force of gravity on a drop, and the drop would hang suspended in mid-air. Some drops have more captured electrons than others, so they will require a higher electrical field to stop. Particles that did not capture any of that extra electrons, were not affected by the electrical field and fell to the bottom plate due to gravity. When a drop is suspended, its weight m · g is exactly equal to the electric force applied, the product of the electric field and the charge - q · E. The values of E, the applied electric field, m the mass of a drop, and g, the acceleration due to gravity, are all known values. So it is very easy to obtain the value of q, the charge on the drop. Millikan repeated the experiment numerous times, each time varying the strength of the x-rays ionizing the air, so that differing numbers of electrons would jump onto the oil molecules each time. He obtained various values for q. The charge q on a drop was always a multiple of 1**.**59 x 10-19 Coulombs. This is less than 1% lower than the value accepted today: 1**.**602 x 10-19 C."

__//-Ernest Rutherford// **1871-1931** New Zealander__

He discovered and identified alpha particles as the nuclei of the atom. The most recognized experiment was his Gold-Foil Experiment. In which by using a radioactive source he shot or directed the rays (alpha particles) at gold and other metallic foils, expecting for the beam to go through with out much difficulty, based on JJThomson’s model of the atom. Surprised to find that rarely the alpha particles would be deflected into a strange angle or almost directly back. Leading Rutherford to conclude that there must have been a dense positively charged ( nuclei) center were, when as a beam was passing through the element, rarely that beam would be deflected by hitting that center.



__//-Niehls Bohr **1885-1962**// Danish__ He is best known for Bohr’s Atomic Model, which shows a positively charged Nuclei surrounded by orbiting electrons that have electrostatic attracting forces. Unfortunately, doubt of the truthfulness of Bohr’s model arose when it was pointed out by the classic mechanics that say, slowly the electromagnetic forces release as the electron orbits around the nucleus –which means slowly the electrons would fall into the nucleus, therefore proving that all atoms and matter is unstable. Bohr then concluded that the electrons travel in orbits that have discrete quantized speeds and therefore quantized energies. That is not every orbit is possible but only certain specific ones, at certain specific distance. Electrons don’t continuously lose energy as the they travel they can only gain or lose energy by jumping from one allowed orbit to another.

__//-Erwin Schrödinger **1887-1961**// Austrian__ Explained the movement of an electron, providing a theoretical basis for the atomic model that Neil Bohr had proposed based on laboratory evidences. Erwin described the movement of the electron as a wave, his theory became known as Shrodinger’s wave equation. Later followed Heisenberg’s Matrix mechanics, which was strictly mathematical. Erwin soon showed that the two theories were identical, only expressed differently.


 * -1905 - Bloody Sunday** was an incident on 22 january, 1905 in Sst.Petersburg, Russia, where unarmed, peaceful demonstrators marching to present a petition to Tsar nicholas ll were gunned down by the Imperial Guard. The event was organized by Father Gapon, who was suspected of being paid by the Okahron, the Tsarist secret police, and thus considered to be its agent provocateur. Bloody Sunday was a serious blunder on the part of the Okhrana, and an event with grave consequences for the Tsarist regime, as the blatant disregard for ordinary people shown by the massacre undermined support for the state. Despite the consequences of this action, the Tsar was never fully blamed, because he was not in the city at the time of protest.

World War I, also known as the First World War, the Great War and the War To End All Wars, was a global military conflict which took place primarily in Europe from 1914 to 1918. Over 40 million casualties resulted, including approximately 20 million military and civilian deaths. The conflict had a decisive impact on the history of the 20th century.
 * -World War I** (1914-1918)

__//-James Chadwick **1891-1974**// English__ 1932- credited with the discovery of the neutron, the third basic but essential component of the nucleus. It increased the mass of the element without adding electrical charge. This not only changed our view of the nucleus, but also provided a new means of probing the nucleus. Because the neutron was relatively massive but neutral, it was scarcely affected by the cloud of electrons surrounding the nucleus or by the positive electrical barrier of the nucleus itself. His discovery and data later helped for the creation of the atomic bomb. The neutron is so essential because they help stabilize the nucleus, they help to reduce repulsion between protons.

Electron Cloud Model- http://www.lionden.com/heliuman.gif

Plum Pudding Model- http://ganymede.nmsu.edu/tharriso/ast301/Thomson1.jpg Rutherford-Bohr Model- http://www.newsandevents.utoronto.ca/bios/askusimages/atomsm.jpg Planetary Model- http://cache.eb.com/eb/image?id=72118&rendTypeId=35 ( neutrons shouldnt be there because they were discovered 50 years later by Chadwick)

BIBLIOGRAPHY

http://plato.standford.edu/entries/leucippus/ http://plato.standford.edu/entries/democritus/ http://www.historyguide.org/intellect/priestley.html http://www.iep.utm.edu/a/aristotl.htm http://www.woodrow.org/teachers/chemistry/institutes/1992/Davy.html http://www.ushistory.org/declaration/related/frin.htm http://content.answers.com/main/content/wp/en/thumb/e/e9/180px-A_New_System_of_Chemical_Philosophy_fp.jpg http://en.wikipedia.org/wiki/John_Dalton http://nobelprize.org/nobel_prizes/physics/laureates/1901/rontgen-bio.html http://imagine.gsfc.nasa.gov/docs/people/Wilhelm_Roentgen.html http://www.britannica.com/eb/article-9083885/Wilhelm-Conrad-Rontgen http://www.accessexcellence.org/AE/AEC/CC/historical_background.html http://www.juliantrubin.com/bigten/millikanoildrop.html http://images.google.com/imgres?imgurl=http://cache.eb.com/eb/image%3Fid%3D22475%26rendTypeId%3D4&imgrefurl=http://concise.britannica.com/ebc/art-18080/The-Rutherford-gold-foil-experiment-In-1911-physicist-Ernest-Rutherford&h=310&w=380&sz=29&tbnid=XVztnuGJv23tJM:&tbnh=100&tbnw=123&prev=/images%3Fq%3Dernest%2Brutherford%26um%3D1&start=3&sa=X&oi=images&ct=image&cd=3 http://nobelprize.org/nobel_prizes/physics/laureates/1935/chadwick-bio.html http://www.visionlearning.com/library/module_viewer.php?mid=50 http://chemcases.com/nuclear/nc-01.htm http://eawc.evansville.edu/chronology/ropage.htm