Famous scientist who contributed to structure of atom!


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Famous scientist who contributed to structure of atom!

  1. 1. Background  Lived from September 6, 1766 – July 27, 1844  English chemist, Meteorologist, And Physicist.  Born into a Quaker family at Eaglesfield in Cumberland, England.  At age of 15 helped his older brother run a Quaker school in nearby Kendal  Dalton was heavily influenced in early life by Elihu Robinson, who was a meteorologist and instrument maker. This got him started into mathematics and meteorology.
  2. 2. Contributions  Color blindness- He lead a lot of research in the area of color blindness and because of it the common term for color blindness became “Daltonism” in his honor.  He was one of the first to even formally publish about color blindness at the time.  He followed this essays with many on different topics such as reflection and refraction of light.  (Fun Fact): He Himself was color blind  Daltons law- The law of partial pressures. Statue of Dalton in Manchester Town Hall
  3. 3. Contributions (cont.)  Daltons Atomic Theory  This theory had five main points  The atoms of a given element are different from those of any other element; the atoms of different elements can be distinguished from one another by their respective relative atomic weights.  All atoms of a given element are identical.  Atoms of one element can combine with atoms of other elements to form chemical compounds; a given compound always has the same relative numbers of types of atoms.  Atoms cannot be created, divided into smaller particles, nor destroyed in the chemical process; a chemical reaction simply changes the way atoms are grouped together  Elements are made of tiny particles called atoms.
  4. 4. Justice  He didn’t actually find or figure out color blindness he just built off other peoples work and did research but it still became commonly known as “Daltonism”  He also didn’t come up with the base of most of his theories for example “Daltons law” (law of Partial Pressures) was really based off Charles’s law (Gay-Lussac’s law)
  5. 5. Early Childhood  Faraday was born in 1791  Grew up near London in slums known as Newington Butts  His father was a blacksmith  Family was poor  Had very little education  Physically weak
  6. 6. fe as A book Binder  Physical handicap led him to bookbinding  Apprentice to master Georges Reibau  Reading and bookbinding  Encyclopedia Brittannica and Conversations on Chemistry  Successor Of Sir Humphry Davy
  7. 7. Discoveries  Electromagnetic Induction  Electrical field and electrical currents  How could he continuously create this phenomena?
  8. 8. Importance Of His Discoveries  The electric generator allowed for electric energy to be produced without the consumption of chemical energy  Using turbines to produce electricity  Using water, steam, coal, oil, wind to power turbines  Electricity on a larger scale
  9. 9. Introduction  Sir Joseph John "J. J." Thomson (18 December 1856 – 30 August 1940) was a British physicist and Nobel laureate.  He is credited with discovering electrons and iso topes, and inventing the mass spectrometer.  Thomson was awarded the 1906 Nobel Prize in Physics for the discovery of the electron and for his work on the conduction of electricity in gases.
  10. 10. What Did He Prove?  Thomson, in 1897, was the first to suggest that the fundamental unit was over 1000 times smaller than an atom, suggesting the sub-atomic particles now known as electrons. Thomson discovered this through his explorations on the properties of cathode rays.
  11. 11. Picture of Cathode Ray Experiment
  12. 12. His Other Works  In 1905 Thomson discovered the natural radioactivity of potassium.  In 1906 Thomson demonstrated that hydrogen had only a single electron per atom. Previous theories allowed various numbers of electrons.
  13. 13. Awards  Royal Medal (1894)  Hughes Medal (1902)  Nobel Prize for Physics (1906)  Elliott Cresson Medal (1910)  Copley Medal (1914)  Franklin Medal (1922)
  14. 14. Introduction  Eugen Goldstein (September 5, 1850 – December 25, 1930) was a German physicist. He was an early investigator of discharge tubes, the discoverer of anode rays, and is sometimes credited with the discovery of the proton.
  15. 15. Background  Born: October 20 1891  Died: July 24 1974  Orgin: Bollington, Cheshire, England  Proffesor of physics at University of Liverpool in 1935
  16. 16. Education  Chadwick attended Manchester high school, he graduated from the Honours School of Physics in 1911. He spent two years under proffesor Rutherford in the Physical Laboratory in Manchester were he worked on radioactivity problems and gained his M.sc degree in 1913.
  17. 17. Discoveries  He discovered the neutron  He also discovered the nucleus of the atom Theories James Chadwicks’ theory that electrons rotate around the nucleus in Disproven defintie pathes was disproven Electrons actually form a cloud around the nucleus
  18. 18. In what period of time did he live and what is his country of origin? August 30, 1871and he died on October 19, 1937 in Brightwater, New Zealand.  …Rutherford born on
  19. 19. When did he conduct his experiment?  He conducted his experiment on……… 1911by Hans Geiger and Ernest Marsden at the suggestion of Ernest Rutherford. Geiger and Marsden expected to find that most of the alpha particles travel to straight trough the foil with little deviation, with a remainder being deviated by a percent or two.
  20. 20. What was he trying to prove w/ his experiment?  Rutherford proving about the existence of …….. Neutrons. It was named by James Chadwick.  Which could somehow compensate for the repelling effect of the positive charges of protons by causing an attractive “nuclear force” and thus keep the nuclei from flying apart from repulsion between protons.
  21. 21. Summarize his experiment (what he did and what he discovered) Gold Foil Experiment
  22. 22.  The gold foil experiment consisted of a series of tests in which positively charged alpha particles (helium nuclei) were fired at a very thin sheet of gold foil. If Thomson's Plum Pudding model was to be accurate, the big alpha particles should have passed through the gold foil with only a few minor deflections. This is because the alpha particles are heavy and the charge in the "plum pudding model" is widely spread.
  23. 23.  In detail, a beam of alpha particles, generated by the radioactive decay of radon, was directed normally onto a sheet of very thin gold foil in an evacuated chamber. A zinc sulfide screen at the focus of a microscope was used as a detector; the screen and microscope could be swivelled around the foil to observe particles deflected at any given angle. Under the prevailing plum pudding model, the alpha particles should all have been deflected by, at most, a few degrees; measuring the pattern of scattered particles was expected to provide information about the distribution of charge within the atom.
  24. 24. Why was he surprised by his experimental results?  Bec. On his experiments, many of the alpha particles did pass through as expected, many others were deflected at small angles while others were reflected back to the alpha source.
  25. 25. How did his results fit w/ Thomson’s view of the atom?  Since none of Thomson's negative "corpuscles" (i.e. electrons) contained enough charge or mass to deflect alphas strongly, nor did the diffuse positive "pudding" or cloudlike positive charge, in which the electrons were embedded in the plum pudding model. Instead, Rutherford suggested that a large amount of the atom's charge and mass is instead concentrated into a very physically small (as compared with the size of the atom) region, giving it a very high electric field. Outside of this "central charge" (later termed the nucleus), he proposed that the atom was mostly empty space.
  26. 26. Describe his model of the atom a number of tiny electrons circled the nucleus like the particles then hypothesized to make up the ring around Saturn. By implication, Rutherford's concentration of most of the atom's mass into a very small core, made some type of planetary model an even more likely metaphor than before, as such a core would contain most of the atom's mass, in an analogy to the Sun containing most of the solar system's mass.
  27. 27. WERE His beliefs accepted by the society at that time?  His beliefs were accepted until one scientist made an experiment regarding Rutherford’s experiment. He is Niels Bohr.
  28. 28. Born On : 7th October 1885 Death : 18th November 1962 Nationality : Danish Field : Physics
  29. 29. In 1912 he married his wife, Margrethe Norlund. He had six childeren, two of them died. One of their sons, Aage Bohr grew up to be an important physicist who recieved the Nobel Prize in 1975.
  30. 30. In 1912 he met and later joined Ernest Rutherford at Manchester University. In 1922, Bohr was awarded the Nobel Prize in physics. Bohr had adapted Rutherford's nuclear structure .
  31. 31. Bohr model of the atom(part I) 1.The electrons can only travel in certain orbits. 2.The electrons of an atom revolve around the nucleus in orbits. Bohr model of the atom(part II) Bohr introduced the idea that an electron could drop from a higher-energy orbit to a lower one, in the process emitting a photon(light quantum) of discrete energy.
  32. 32. Thank You =‘)