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How science changes


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How science changes

  1. 1. How Science Changes Leslie Prohaska Florida State University SCE5943 Field Lab Internship Dr. Alejandro Gallard October 19, 2009
  2. 2. The story of Pangea <ul><li>Remember how the theory of plate tectonics developed </li></ul><ul><li>Alfred Wegener proposed his idea of continental drift in his 1915 book, The Origin of Continents and Oceans </li></ul><ul><li>His evidence included fossils of the same lizard and same plant being found on the eastern side of South America and western side of Africa </li></ul><ul><li>This was not enough though… </li></ul>
  3. 3. More evidence needed <ul><li>When technology improved after World War II, scientists were able to map the floor of the ocean </li></ul><ul><li>Magnetic stripes were found on the sea floor which proved that the sea floor was spreading </li></ul><ul><li>The theory of plate tectonics was finally accepted in the 1960’s because of this evidence </li></ul>
  4. 4. This is how science works <ul><li>Scientists continue to experiment, to make observations, take data, and collect evidence </li></ul><ul><li>As technology improves, there are new ways to experiment and to make these observations </li></ul><ul><li>If this new information does not fit with the old explanations or, then scientists will make new theories to explain their findings </li></ul><ul><li>Yes, scientists can change their minds! </li></ul>
  5. 5. Science is about improving our understanding <ul><li>The history of science reveals both evolutionary and revolutionary changes. With new evidence and interpretation, old ideas are replaced or supplemented by newer ones. (NSTA Board of Directors, 2000) </li></ul><ul><li>Progress in science consists of the development of better explanations for the causes of natural phenomena. (Teaching about Evolution and the Nature of Science, 1998, p.42) </li></ul><ul><li>Explanations that we discuss today may continue to change. </li></ul>
  6. 6. Other examples… of the nature of science… that we have Discussed before
  7. 7. The Atomic Theory <ul><ul><li>Democritus, ‘atomos’ </li></ul></ul><ul><ul><li>Dalton, 1808, all matter is made of atoms </li></ul></ul><ul><ul><li>JJ Thomson, 1897, plum pudding model </li></ul></ul><ul><ul><li>Rutherford, 1909, gold foil experiment, most of the atom is open, empty space </li></ul></ul><ul><ul><li>Bohr, 1913, orbits and energy levels </li></ul></ul><ul><ul><li>Modern atomic model, wave mechanics model, 1926 </li></ul></ul>
  8. 8. The Cell Theory <ul><li>Robert Hooke, 1665, first saw cells in microscope and thought they looked like little rooms he called cells </li></ul><ul><li>Matthias Schleiden –1837, all plants are composed of cells </li></ul><ul><li>Theodore Schwann – 1839, all animals are composed of cells </li></ul><ul><li>Modern Cell Theory – 1858, 1) cells are the basic unit of life, 2) all organisms are composed of one or more cells, 3) all cells arise from preexisting cells </li></ul>
  9. 9. History of classification <ul><ul><li>Aristotle – 350 B.C. 2 large groups, plants and animals </li></ul></ul><ul><ul><li>Carolus Linnaeus – 1753, kept two kingdoms but broke them into smaller groups and had everyone use Latin </li></ul></ul><ul><ul><li>Five kingdom system, 1959, Animal, Plant, Fungi, Protists, Moneran, Whittaker </li></ul></ul><ul><ul><li>Six kingdom system proposed/Three domains???? Still not resolved </li></ul></ul>
  10. 10. Things continue to change <ul><li>As scientific knowledge evolves, major disagreements are eventually resolved… (National Science Education Standards, 1996, p. 171) </li></ul><ul><li>This is part of scientific inquiry </li></ul>
  11. 11. References <ul><li>American Association for the Advancement of Science. (1990). Chapter 1: The Nature of Science. Retrieved October 17, 2009, from </li></ul><ul><li>National Science Education Standards observe, interact, change, learn. (1996). Washington, DC: National Academy Press. </li></ul><ul><li>NSTA Board of Directors. (2000, July). Nature of Science Position Statement - NSTA Position Statements. Retrieved October 17, 2009, from </li></ul><ul><li>Teaching about evolution and the nature of science . (1998). Washington, DC: National Academy Press. </li></ul>