Fall.2008.MMA.Pimentel.Timeline

History of The Atom!

Armand Pimentel Dr. Jesse Reich Chemistry 1 - 10:45 October - November 2008

Democritus (460 - 370 B.C.) Plato (428B.C. -347 B.C.) Aristotle (384 - 322 B.C.) William Crookes (1832-1919) Wilhwlm Roentgen (1845 - 1923) John Dalton (1766-1844) JJ Thompson (1856-1940) Marie Curie (1867 - 1934) Henry Bequerel (1852 - 1908) Albert Einstein (1879-1955) Robert Millikan (1868 - 1953) Ernest Rutherford (1871 - 1937) Niels Bohr (1885 - 1962) Erlwin Schrodinger (1877 - 1961) James Chadwick (1891 - 1974) Wermer Heisenburg (1901 - 1976)
 * __ATOMIC HISTORY TIME - LINE UP!__**

__**Democritus (460-370 B.C.)**__ Year of Discovery: 410 B.C.__**
 * __Greece



Democritus was all famous for his production of the Atomic Theory. This theory stated that atoms were indestructable and the smallest particles of life. Atoms is devised from the word "Atomos", meaning indivisible in the Greek language.

//Pictures from:// http://www.nndb.com/people/790/000087529/democritus-1-sized.jpg and ... http://darkwing.uoregon.edu/~ch111/images/democritus.gif

Greece Year of Discovery: 360B.C.__**
 * __Plato

Plato who didnt agree wth Democritus, moved on to study more about atoms, that everything had to be made of something smaller. He then moved on to study the five Platonic Solids. "Plato was mightily impressed by these five definite shapes that constitute the only perfectly symmetrical arrangements of a setof (non-planar) points in space, and late in life he expounded acomplete "theory of everything" (in the treatise called Timaeus) based explicitly on these five solids." (http://www.mathpages.com/home/kmath096.htm) __pictures:__ (http://myhero.com/images/guest/g41359/hero36342/g41359_u38898_plato.jpg) (http://people.bu.edu/wwildman/WeirdWildWeb/media/galleries/philosophy/ancient/Plato2.jpg)

Aristotle (384-322 B.C.) __Year of Discovery:__ 347-322B.C.  **
 * __Greece__

Aristotle didn't like Democrates' theory. He claimed that there was no smallest part of matter and that different substances were made up of proportions of fire, air, earth, and water. As there were of course no experimental means available to test either view, Aristotle's prevailed mainly because people liked his philosophy better. http://improbable.org/era/physics/atom.html

Pictures from: http://www.critix.co.uk/img/Businessman-Aristotle.gif and ... http://www.cs.utk.edu/~Mclennan/BA/AGEDE/images/elemsquare.gif

__**John Dalton (1766-1844) England Year of Discovery: 1798 **__

John " Jesse Reich" Dalton was a English Chemist who came up with his Atomic Theory.

 ==__**Dalton's Atomic Theory**   __1) All matter is made 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. ==

(Dr. Reich, presentation. Fall 2008, week 4 lesson 1.)

Pictures : http://www.elektromania.net/images/96D9_john_dalton7.jpg and.. http://www.uh.edu/engines/jdsymbols.jpg

England Year of Discovery: 1870__**
 * __William Crookes (1832 - 1919)



William Crookes was respnsible for his invention of the Crookes Tube. The tube was in face at a vacume state with one end of the glass tube attached to a enectrical source. When charged there was turned on a greeen ligh was noticed shining inside the tube. The ray was soo known as a "cathode ray'. Crookes looked deeper into his expirment and held a magnet up to the beam of light, and watch as the cathode ray deflected away from its strait course. Crooks concluded that the cathode ray was made up of particles, and that the particles carried some sort of electrical charge. (http://bhs.cusd220.lake.k12.il.us/Chemistry_Web/Chem%20history/crookes/crookes.htm)

pictures: http://www.chem.ox.ac.uk/icl/heyes/lanthact/biogs/crookes.html

Germany Year of Discovery: 1874
 * __Wilhelm Roentgen (1845 - 1923)

__**

Willhelm Roentgen is responsible for his most important discovery of the Xray. On November 8, 1895 Roentgen found 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 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 called his 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. (http://nobelprize.org/nobel_prizes/physics/laureates/1901/rontgen-bio.html) picture: http://img504.imageshack.us/img504/41/404be8.jpg (http://web.ct.infn.it/~rivel/Archivio/roentgen.jpg)

France Year of Discovery: 1896 __** Henri Bequerell is a famous French scientist who is most famous for his "mistake" during his study of radiation. After leaving radiated salt in his drawer for a period of time, after he got them developed he notice the images of the salts to be very clear and strong. This stated that uranium emmited radioactivity without a outside source such as the sun. "Becquerel decided to investigate whether there was any connection between X-rays and naturally occurring phosphorescence. He had inherited a supply of uranium salts, which phosphoresce on exposure to light. When the salts were placed near to a photographic plate covered with opaque paper, the plate was discovered to be fogged. The phenomenon was found to be common to all the uranium salts studied and was concluded to be a property of the uranium atom. Later, 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. For his discovery of spontaneous radioactivity Becquerel was awarded half of the Nobel Prize for Physics in 1903," (http://nobelprize.org/nobel_prizes/physics/laureates/1903/becquerel-bio.html) (Dr. Reich, fall 2008, week 4 lesson 1)
 * __Henri Bequerell (1852 - 1908)

__pictures:__ __**(**__http://www.mlahanas.de/Physics/Bios/images/HenriBecquerel.jpg__)__ (http://i206.photobucket.com/albums/bb103/ken_winstonitoh/Becquerel_plate.jpg)

Year of Discovery: 1898__**
 * __JJ Thompson (1856 - 1940)__**
 * __England

J.J Thompson took chemistry to a brand new level after his discovery of the electron particle. The brand new idea of a negatively charged particle smaller than an atom stunned almost all. Thompson Deveopled a model, known as the Plum Pudding Model, showing that negatively charged electrons are held together in a sphere of positive charge. Scientists of the time were dead set on atoms being the smallest particles of life, Thompson on the other hand, proved them to be very wrong. (info from page 93 of Introductory Chemistry, Nivaldo Tro)

France Year of Discovery: 1898__**
 * __Marie Curie (1867 - 1934)

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. Mme. 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. She was awarded half the nobel prize in 1903. (http://nobelprize.org/nobel_prizes/physics/laureates/1903/marie-curie-bio.html) pictures: (http://myweb.dal.ca/lt531391/curie.jpg) (http://www.famous-scientists.net/images/MarieCurie.jpg)

__**Albert Einstien (1879-1955) Germany Year of Discovery:** **1905** __ "Einstein, his major contribution was the recognition that the speed of light in a vacuum is constant and an absolute physical boundary for motion. This does not have a major impact on a person's day-to-day life since we travel at speeds much slower than light speed. For objects travelling near light speed, however, the theory of relativity states that objects will move slower and shorten in length from the point of view of an observer on Earth. Einstein also derived the famous equation, //E = mc2,// which reveals the equivalence of mass and energy" (http://www.allaboutscience.org/theory-of-relativity.htm) His reasearch soon led to the creation of the Atom bomb, which is known as the greatest mistake of his life. (http://www.doug-long.com/einstein.htm)

__pictures:__ (http://hunternuttall.com/blog/wp-content/uploads/2008/07/albert-einstein.jpg) (http://www.xtraordinarypeople.com/media/images/celebrity/full/Albert-Einstein.jpg)

Robert Millikan (1868 - 1953) United States Year of Discovery: 1908

[|**http://www.youtube.com/watch?v=XMfYHag7Liw&feature=related**] **--** A short clip showing Millikan's Oil Droplet Experiment in action (sorry sound doesnt work) Robert Millikan is most famous for his discovery of the charge of an electron. He did this by builing an inclosed container and spraying a fine mist of oil into it, then charging a positive and negative metal plate until the charged droplets seemed as if to be hanging in mid air. he verified experimentally Einstein's all-important photoelectric equation, and made the first direct photoelectric determination of Planck's constant h (1912-1915). In addition his studies of the Brownian movements in gases put an end to all opposition to the atomic and kinetic theories of matter. (http://corrosion-doctors.org/Biographies/MillikanBio.htm) (http://www.juliantrubin.com/bigten/millikanoildrop.html)

pictures: (http://www.uh.edu/engines/robertmillikan.jpg) (http://people.clarkson.edu/~ekatz/scientists/millikan_scheme2.jpg)

Ernest Rutherford (1871 - 1937) England
 * __Year of Discovery: 1909__**

http://www.youtube.com/watch?v=5pZj0u_XMbc __//-- A short clip showing the Gold Foil Expirment in Action.//__

Rutherford researched on the properties of the radium emanation and of the alpha rays, a method of detecting a single alpha particle and counting the number emitted from radium was devised. 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 centre. He discovered all of this through his "Gold Foil Expiriment." He shot alpha particles at a peice of gold foil, but every once and while one would bounce a different way, showing there was a denser part of the gold atoms, the nucleus. (http://nobelprize.org/nobel_prizes/chemistry/laureates/1908/rutherford-bio.html)

__pictures:__ (http://www.astrosurf.com/luxorion/Physique/rutherford-ernest.jpg) (http://www.geo.arizona.edu/xtal/nats101/7_3.jpg)

Denmark Year of Discovery: 1913__**
 * __Neils Bohr (1885 - 1962)



Recognition of his work on the structure of atoms came with the award of the Nobel Prize for 1922. he succeeded in working out and presenting a picture of atomic structure that, with later improvements, still fitly serves as an elucidation of the physical and chemical properties of the elements. Bohr's planetary model of the atom shows a serious of protons and electrons, spinning around a dense circle called the nucleus. (http://nobelprize.org/nobel_prizes/physics/laureates/1922/bohr-bio.html) (http://csep10.phys.utk.edu/astr162/lect/light/bohr.html)

Picture: (http://www-outreach.phy.cam.ac.uk/camphy/nucleus/side7_nucleus.jpg) (http://physics.wustl.edu/cmw/318quantum/Niels_Bohr.jpg)

Austria Year of Discovery: 1926__**
 * __Erwin Schrödinger (1877 - 1961)

Schrödinger introduced a theory described wave equation that is now known as the Schrödinger equation. The solutions to Schrödinger’s equation are wave functions that can only be related to the probable occurrence of physical events. In 1933 he shared the Nobel Prize for physics with Paul Dirac for his contributions to atomic theory. He continued his studies of the application and statistical interpretation of wave mechanics, the mathematical character of the new statistics, and the relationship of these statistics to statistical thermodynamics. He also worked on problems of general relativity and cosmology and on a unified field theory. Late in his life Schrodinger studied the foundations of physics and their implications for philosophy (http://www.britannica.com/EBchecked/topic/528287/Erwin-Schrodinger) (http://library.thinkquest.org/15567/bio/schrodinger.html)

pictures: (http://www.hmi.de/bereiche/SF/SF7/PANS/english/nobel/Schroedinger/Schroedinger_01.jpg)

England Year of Discovery: 1932__**
 * __James Chadwick (1891 - 1974)

"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 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. For this epoch-making discovery he was awarded the Hughes Medal of the Royal Society in 1932, and the Nobel Prize for Physics in 1935" (http://nobelprize.org/nobel_prizes/physics/laureates/1935/chadwick-bio.html)

pictures: (http://wwwlapp.in2p3.fr/neutrinos/neutimg/nacteurs/chadwick.jpg) (http://www.chemistryexplained.com/images/chfa_01_img0179.jpg)

__**Wermer Heisenburg (1901 - 1976) Germany**__
 * __Year of Discovery: 1939__**

"Heisenberg's name will always be associated with his theory of quantum mechanics. For this theory and the applications of it which resulted in the discovery of forms of hydrogen, Heisenberg was awarded the Nobel Prize for Physics for 1932. His new theory was based only on what can be observed, on the radiation emitted by the atom. We cannot, he said, always assign to an electron a position in space at a given time, nor follow it in its orbit, so that we cannot assume that the planetary orbits postulated by Niels Bohr actually exist. Mechanical quantities, such as position, or velocity, should be represented, not by ordinary numbers, but by abstract mathematical structures called "matrices" and he formulated his new theory in terms of matrix equations. 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." (http://nobelprize.org/nobel_prizes/physics/laureates/1932/heisenberg-bio.html)

pictures: http://www.germannotes.com/archive/images/heisenberg.jpg