Daniel.pye.atomichistory.fall.2009

=====The History of an Atom=====

Atomic history timeline by Daniel Pye

- 460 BC to 370 BC - - Democritus was born around 460 BCE- - Born in Abdera, Greece- - Discovered atoms- Democritus was one of the founders of the ancient atomist theory. He was an atomist that believed that there are small indivisible materials that everything is composed of. He believed that atoms come in various a number of sizes that are perfectly solid. Atoms themselves are eternal and many of Democritus’s discoveries were tested and analyzed by Aristotle. http://plato.stanford.edu/entries/democritus/
 * Ancient Times **
 * Democritus **

** Plato ** - 429 BC - 347 BC - -Born in Greece definite place unknown- -Discovered Small Particles 360 BC- Plato was a student of Socrates who helped lay the foundation of natural philosophy. He was a classical Greek philosopher that took in all the wisdom of Socrates. Plato was not fully credited for the discovery of small particles although his wisdom on that area of science became well known.

-384 BC to 322 BC - Born in Stageira, Greece Discovered reality in Ideas or eternal forms- Through Aristotle’s experiences he saw the reality of physical objects and what they composed of. He knew that matter and the shape of organisms played a significant role in what we see. Much of Aristotle’s wisdom came from Plato, along with many of his beliefs and theories. [] -1728-1799- - Bordeaux April 16th, 1728- -Discovered fixed air- Black discovered that gas could combine with a solid. His discoveries mainly fixed air contributed to the science of atoms. All matter and how different types combine, led to a better understanding of the chemical nature of gases. [] -(1766 -1844 )- -Born in England- -Discovered Atomic Theory- John Dalton was an English meteorologist who was intruiged by chemistry because of his visions upon the atmosphere. He proposed the Atomic Theory in 1803 which stated that (1) all matter was composed of small indivisible particles termed atoms, (2) atoms of a given element possess unique characteristics and weight, and (3) three types of atoms exist: simple (elements), compound (simple molecules), and complex (complex molecules). [] -(1743 -1794)- -Born in France - -Discovered the role of oxygen in combustion- Laviosier changed chemistry from a qualitative to a quantitative science. He freed society from the disillusionment of the phlogiston theory by showing that the mass of the products in a reaction are equal to the mass of the reactants.
 * Aristotle **
 * 1700-1800 **
 * Joseph Black **
 * John Dalton **
 * Antoine Laurent Lavoisier **

-( 1845 - 1940 )- -Born in Germany- -Discovered the X-ray- Roentgen was born in 1845 in north-western Germany. “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. During subsequent experiments he found that objects of different thicknesses interposed in the path of the rays showed variable transparency to them when recorded on a photographic plate. When he immobilised for some moments the hand of his wife in the path of the rays over a photographic plate, he observed after development of the plate an image of his wife's hand which showed the shadows thrown by the bones of her hand and that of a ring she was wearing, surrounded by the penumbra of the flesh, which was more permeable to the rays and therefore threw a fainter shadow. This was the first "röntgenogram" ever taken. In further experiments, Röntgen showed that the new rays are produced by the impact of cathode rays on a material object. Because their nature was then unknown, he gave them the name X-rays. Later, Max von Laue and his pupils showed that they are of the same electromagnetic nature as light, but differ from it only in the higher frequency of their vibration.” (nobelprize.org)
 * 1800-1875 **
 * Wilhelm C Roentgen **

-(1785 –1850)- -Born in Glousechshire- -Discovered atomic weights- Discovered that the atomic weights of all chemical elements are whole-number multiples of the atomic weight of hydrogen. Prout suggested that hydrogen might be the primary matter from which all other "elements" were formed. http://www.clinchem.org/cgi/content/full/49/4/699
 * William Prout **

-( 1832 - 1919 )- -Born in England- -Discovered the Crookes Tube- In 1861, while conducting a spectroscopic examination of the residue left in the manufacture of sulphuric acid, he observed a bright green line which had not been noticed previously, and by following up the indication thus given he succeeded in isolating a new element, thallium, a specimen of which was shown in public for the first time at the exhibition of 1862. From there he was led to his famous researches on the phenomena produced by the discharge of electricity through highly exhausted tubes known as Crookes tubes.
 * William Crookes **


 * 1875-1900- **

-(1856 -1940 )- -Born in England- -Discovered the Electron in 1898- Thomson was experimenting with electric discharge in a high-vacuum cathode-ray tube when he discovered the electron. In 1904 he suggested a model of the atom as a sphere of positive matter in which electrons are positioned by electrostatic forces. Thomson used a plumb pudding model to finally prove that electrons existed. http://www.chemheritage.org/classroom/chemach/atomic/thomson.html
 * Joseph J Thomson **

-( 1867 - 1934 )- -Born in France- -Discovered Polonium 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. Her discoveries led to the promotion of radium to alleviate suffering during World War One. Curie was awarded numerous awards for her discoveries and the importance of them.
 * Marie Curie **

[] ** Henri Becquerel ** -( 1852 - 1908 )- -Born in France- -Discovered Radioactivity- Becquerel received the Nobel prize in 1903 for his discoveries of radioactivity. His technique was to wrap a photographic plate in light tight black paper, position the mineral on the plate, and leave the experiment on his window sill where sunlight would stimulate the mineral to glow, discovering radiation. Many of his main researches included optics, magnetic fields, infer red, and the absorption of light, with these researches, Becquerel obtained his doctorate from the Faculty of Sciences of Paris. http://www.vigyanprasar.gov.in/scientists/AntoineHenriBecquerel.htm

-( 1868 - 1953 )- -Born in the USA- No resemblance to Bruce Springsteen -Discovered the Charge of an Electron- Millikan made many discoveries mainly in the fields of electricity, optics, and molecular physics. One of his first and major discoveries was the charge of an electron using the **falling drop method**. He also proved that this quantity was a constant for all electrons and could demonstrate the atomic structure for electricity. [] -( 1885 - 1962 )- -Born in Denmark- -Discovered the Bohr Atom – Bohr is best known for the study of atomic structure and also for work on radiation. He studied the structure of atoms on the basis of Rutherford's discovery of the atomic nucleus. By introducing conceptions borrowed from the Quantum Theory. Bohr created the Bohr model. In the Bohr Model the neutrons and occupy a dense central region called the nucleus, and the electrons orbit the nucleus much like planets orbiting the Sun. [] -( 1871 - 1937 )- -Born in England- -Discovered the nuclear theory of an atom- Emigrated from New Zealand Rutherford was a hard worker and a good student. Once in college he met J.J. Thomson, who encouraged him to study atomic physics. He showed that every radioactive element decreases in radioactivity over a unique and regular time, or half-life, ultimately becoming stable. In 1901 and 1902 he worked with Frederick Soddy to prove that atoms of one radioactive element would spontaneously turn into another, by expelling a piece of the atom at high velocity. http://www.pbs.org/wgbh/aso/databank/entries/bpruth.html -1915-1950-
 * 1900-1915 **
 * Robert Millikan **
 * Niels Bohr **
 * Ernest Rutherford **

-( 1877 - 1961 )- -Born in Austria- -Discovered electromagnetism – Schrodinger was a student at the University of Vienna from 1906 to 1910. Through his studies he published many papers on the problem of unifying gravitation and electromagnetism. After his retirement he returned to an honored position in Vienna. He died on the 4th of January, 1961, after a long illness.
 * Erwin Schrodinger **

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