Camperchioli.Chisholm.atomichistorytimeline.fall.2010

__// Ancient Times: //__


Leucippus- Very little is known about Leucippus or his findings in atomist theory. He was born in the 5th Century and is considered to be the founder of atomism. His relationship with Democritus was a subject of great controversory in the nineteenth century scholarship. ---



Democritus is considered to be the father of the atomic theory. He and his mentor Leucippus were among the first to speculate on the nature of the world around them. He was most well known for his idea that everything in the world was made up of smaller things of the same type. For instance, a tree was made up of millions of tiny trees. Perhaps not so surprising in the dog-eat-dog world of ancient Greece, there were many who did not like and even hated Democritus and everything he stood for. Plato, the well-known philosopher, was one who felt particularly stongly that Democritus' values were the ravings of a lunatic. He is said to have denounced Democritus on street corners and even had his books burned. One would think that a philosopher of all people would be open to different ideas.

Democritus believed that atoms were tiny, solid spheres. There were no electrons or nuleus' in his model. What you see is what you get. ---



Lucretius was a Roman philosopher/thinker who came years after Democritus. Not much is known about him besides the fact that he died at 44 years of age. In a text that he wrote: //De Rarum Natura//, he introduced the idea that atoms were held together by tiny hooks like so many pieces of Velcro (TM).

--- __// 1700-1800 //__




 * Antoine Lavoisier was born in 1743 to an upper class family in France. As a member of the social elite he was given a first class education.**
 * It was through his schooling that he found a love for chemistry. In his adult life, Lavoisier discovered that water is made up of Hydrogen and Oxygen.**
 * He also was the first to dicover the Law of Conservation of Mass, which states that elements in a chemical reaction are neither created nor destroyed,****but only rearranged into different compounds. These feats of fiery intellect led Lavoisier to be called the father of modern chemistry.**
 * At the height of the French Revolution, in 1794, Lavoisier was gilloutined to a cheering crowd. They must have all failed chemistry in high-school.**


 * Joseph Proust was the man we can all thank for the concept of stoichiometry.****He said that compounds contain proportions of elements by weight.**
 * He came up with this stroke of brilliance in 1799- a mere 4 decades after Lavoisier's Law of Conservation of Mass.**



just kidding, that's the John Dalton who played in the popular British band of the 60's and 70's //The Kinks//

This is the real John Dalton here. His atomic theory is considered the theoretical foundation of chemistry.He started out a modest english chemist with a quaker background. Dalton's atomic theory had four basic parts: all matter is made up of atoms, which are indivisible and indestructable. All atoms of the same element are the same in mass and properties. Compounds are formed by a combination of two or more kinds of elements. A chemical reaction is a rearrangement of atoms. Dalton organized the elements into the first crude periodic table. Some of it was wrong and all of it was based on circumstantial evidence, but then again some of it was right too. As you can see, the compounds at the bottom of the table are clearly bonded together. However, as Dalton didn't know electrons existed, he seemed unsure of how to go about joining them.

=__// 1800-1875 //__=



Michael Faraday- Michael Faraday was the inventor of the electric motor. He was also the inventor of the induction ring which became the first electric transformer. He attached two wires through a sliding contact to a copper disc. He did significant work in electrochemistry stating the first and second laws of electrolysis. At a young age, Faraday was a curious boy, always feeling the urge to learn more. When he was thirteen years of age, he was an errand boy for a bookbinding store in London.


 * Julius Plucker- University of Bonn 1 year of working with vacuum tubes. He found that the discharge caused a fluorescent glow to form on the glass**
 * walls of the vacuum tube, and that the glow could be made to shift by applying** **an electromagnet to the tube, thus creating a magnetic field.**
 * It was later shown** **that the glow was produced by cathode rays.**

=__// 1875-1900 //__= =  =
 * Dmitri Mendeleev-was the first to organize the elements into what is now the periodic table.**
 * Mendeleev published his periodic table of all known elements and predicted** **several new elements to complete the table.**
 * Mendeleev also investigated the composition of oil fields, and helped to found** **the first oil refinery in Russia.**
 * In 1893, he was appointed Director of the Bureau of Weights and Measures. It was** **in this role that he was directed to formulate new state standards**
 * for the** **production of vodka.**

// Marie Sklodowska Curie was the most badass chemist ever. // // She discovered radioactivity (a term that she herself coined) at a time when women were frowned upon in a male-dominated society. // // She and her husband Pierre, whom she met in school through a mutual interest in the magnetic properties of various steels, // // discovered three different radioactive metals: Polonium, Radium, and Thorium. The Curie's found these by separating them // // out from a ton of pitchblende. Literaly a ton. Of course, at that time no one knew that radiation could kill you. Marie Curie died of // // radiation poisoning at a relatively young age. And how did Pierre die? In a horse and buggy accident of course. And before the // // advent of the Euro, the Curies graced the face of the 500 Franc note. And then the Euro came and built up the European economy // // by unifying all those countries and making it very expensive for American tourists to visit their ancestor's homeground and other // // historic landmarks. //

//Ernest Rutherford:// Was one of the first to design highly original experiments with high-frequency, alternating current. His papers were published in 1896, his second one was called "Magnetic Viscosity." He also worked with Thomson with the behavior of ions observed in the gases that were treated with x-rays. His first researches were in New Zealand where he wrote "Magnetization of iron by high frequency discharges," which was his thesis. He was knighted in 1914, and was appointed to the order of the merit in 1925. He was also created first Baron Rutherford of Nelson, New Zealand and Cambridge in 1931. He was awarded several medals in the field of science for his contributions including the Nobel Prize in 1908.

Niels Bohr proposed the Bohr Model of the Atom in 1915. Since the Bohr Model is slightly different from the earlier Rutherford Model, some people call Bohr's Model the Rutherford-Bohr Model. The modern model of the atom is based on quantum mechanics. The Bohr Model contains some flaws, but it is important because it describes most of the accepted features of atomic theory without all of the high-level math of the modern version. Unlike similar prior models, the Bohr Model explains the Rydberg formula for the spectral emission lines of atomic hydrogen. // - --//

// Henri Becquerel is really in this timeline by accident. He exposed photographic plates to a sample of uranium. This, by the radioactive properties //// of the element, developed the plates without the presence of the sun. He called the emissions of radiation "xrays." For the life of me I can not //// figure out why. // // - //

William Rontgen was probably the most unlucky of the scientists in this wiki. He accidentally discovered xrays while reasearching the glow produced by cathode rays. The experiments he conducted took place in a dark room and he happened to see a bottle glowing on the shelf. Of course he immediately called his wife into the room and made her hand glow- first with the light of the xray and then with the radiation burns the xrays produced. The reason he is unlucky is because of what his wife no doubt put him through in the aftermath of his little "mistake." After all, how was he to know xrays would burn skin? -- =__// 1900-1915 //__=


 * Neils Bohr- liquid droplet theory permitted the understanding of the mechanism of** **nuclear fission, when the splitting of uranium was discovered by Hahn and** **Strassmann, in 1939, and formed nobelprize.org coppenhagen university.**
 * This is called the electron cloud model. It illustrates a positively charged nucleus surrounded by negatively charged particles.**



The atomic Planetary Model was devised by Ernest Rutherford. Although the model did not make great strides in explaining the electron structure of the atom, it did lead to Rutherford's Gold foil experiment. This model found that the electron cloud of the atom does not influence alpha particle scattering. Large numbersof the atom's charges, up to a number equal to about half the atomic mass in hydrogen units, are concentrated in very small volume at the center of the atom. These deflect both alpha and beta particles.




 * Robert Millikan- During his early years at Chicago he spent much of his time preparing** **textbooks and simplifying the teaching of physics**
 * occupied himself with work concerning the hot-spark spectroscopy of the elements** **(which explored the region of the spectrum between the ultraviolet and X-****radiation.**


 * J J Thomson is possibly the most important modern atomic scientist of them all. While working in the lab one day with cathode ray tubes, J. J. Thomson dicovered the electron. That's right, this guy found and validated the existence of a paticle tiny enough to be assigned a relative weight of 0. He must have had some really strong glasses. Really strong glasses.**


 * J.J. Thomson developed what we now call the plum pudding model. The positively charged material is the pudding, and the negative electrons are like plums, floating around here and there. This was replaced by the electron cloud model of Bohr.**
 * Citations: about.com**
 * nobelprize.com**
 * google.com (google images)**
 * wikipedia.com**
 * wikipedia.com**