GST 2420: Atoms and Stars
An Historical Introduction to Astronomy, Physics, and Scientific Discovery.
Fall 2002, Section 983, Call Number 16050
Agenda 11 for 11/13

  1. Announcements:
    1. Day scheduled as a Friday (noAtoms and Stars class) - November 27
    2. Course web site: http://www.cll.wayne.edu/isp/drbowen/aasf02 (also links from Pipeline). New today: supplementary information for GST 1990 (now vocabulary for Chapter 7 of God and Nature).
    3. Online Life at WSU updated and with live links at http://www.cll.wayne.edu/isp/drbowen/OnlineLife.
    4. Fliers for ISP 5660 / GIS 3340 (Creativity: Building the New) online. How do online courses work? For a general description, see Online Live at WSU, above. To see this course the last time it was taught (when it was AGS 3360) go to http://www.cll.wayne.edu/isp/drbowen/crtvyw02.
    5. For Essay 2, article by Bronowski starts on Reader Pg 254, article by Nissani on Pg 261. Read these for next week.
  2. Personal remarks
    1. Agency
    2. Science as a social process
    3. Are there scientific revolutions? Some people say no - the changes are too gradual
    4. Telescope experiment
  3. Science in the news
    1. What makes us decide that a line or edge is straight? Weight. Equivalence of acceleration field and gravitational field. Advance of the perihelion (point of closest approach to sun, opposite the aphelion or point of greatest distance) of Mercury.
    2. Some other big ideas in Physical Science that will not be much covered here:
      1. Thermodynamics and Statistical Mechanics - irreversibility - the amount of disorder or entropy always increase. For example, putting a container of hot water and a container of cold water in good contact with each other always results in warm water. The warm water never separates back into hot and cold, although energy considerations alone would not forbid this. The impact is that energy can never be recycled the way matter ("stuff") can. Thermodynamics is the field that first established this; Statistical Mechanics is the field that explains why. The why is that there is a very much larger number of ways for the molecules in the water to be arranged with the water warm than there are for it to be separated into hot and cold.
      2. Plate Techtonics, also known as "Continental Drift" - the continents, heated from below, move around the earth's surface like a skin on boiling milk or pudding.
  4. Final exam
    1. New questions for list - fields coming together, example of light, carry over from old
      1. Describe one case in which two expanding fields of science met. What happened within each field. What happened outside of these fields?
      2. (#10 from Midterm list) Compare the contributions of Aristotle and Archimedes to modern science. How did their approaches or methods differ? How does each compare with modern approaches to science?
    2. What should be on info sheet? My goal here.
    3. Start review.
  5. Readings: Atomic theory of Matter. "Second Scientific Revolution"
    1. Steps:
      1. Invention of classical chemistry and Antoine Lavoisier (1743 - 1794, pronounced lah vwahz YAY). Up until this time, chemistry was almost entirely a black art. It was important economically, but chemistry was mainly done through recipes.
        1. The idea of an element - cannot be broken down, other substances are made up of it, but it is not made up of anything else. Still the Aristotelian elements - air, earth, fire and water.
        2. Stephen Hale, 1727 - could heat many substances and drive off large quantities of "air" (we would call it gas today) - air was not a single substance.
        3. William Cullen and Joseph Black - evaporation cooled the liquid left behind. Supposed to be liquid dissolving in air, but this happened even in a vacuum, with no air in which to dissolve.
        4. Turgot - quality of air to fill the container. Happened because fire attached to the air. Water could take on solid, liquid and gaseous states, even in contact with each other.
        5. Black heated chalky substances and drove off air, by weighing materials left behind, found that this air had weight. Air was fixed in the solid before, released by heat, also by acid. This air, however, stopped flames (CO2).
        6. Joseph Priestly collected many different airs, heated calx. Calx - compounds of a metal with oxygen, can heat the metal and drive off some of the oxygen or heat it with carbon and be left with the pure metal and a gas ("air"). Calx weighed more than metal. Phlogiston theory of combustion, released during combustion, can be returned by heating with charcoal to form pure metal again. But did phlogiston have a negative weight?
        7. Lavoisier collected air from heated calx, did not support combustion, so must be "fixed air." But calcination will not take palce in an atmosphere of fixed air. Heated in closed containers, weighed same after as before, so fire or heat did not carry off any matter. Could heat calx of mercury without charcoal and it would turn into mercury metal and air, supported combustion. Could reduce volume by adding nitrous oxide ("nitrous air"), acted like common air, but he could have added more air and gotten a greater reduction. Priestly added more and got a further reduction. Also extremely good air (e.g. mouse lived a very long time).
        8. Lavoisier hypothesized that common air was actually a mixture, called it oxygen ("acid former").
        9. "Inflammable air" (hydrogen) - Cavendish sparked this with common air, formed a dew later found to be water (so water was not an element).
        10. Oxygen theory of combustion, new set of names for chemicals based on this. Changed "air: to "gas" and used "air" for former common air.
        (Idea of an atom. Very small, gas is mostly empty space. At same temeprature and pressure, all gases have the same number of atoms in each volume, different densities are due to the different weights of the atoms.In a solid, atoms are fixed rigidly to each other, in a liquid the atoms stay close together but can slide around. Atoms have different weights and shapes, but mostly just blobs. 90 naturally occurring types, these are the elements.)
      2. Atomic model, for gases. John Dalton (1766 - 1844)
        1. (From Gerald Holton, Introduction to Concepts and Theories in Physical Science, 1973) Dalton apparently became convinced of the existence of atoms through a misreading of Newton's Principia. Dalton was interested in why gases did not stratify by density in the atmosphere, and thought that Newton wrote that atoms in a gas attracted each other gravitationally, and that this is what kept them up.)
        2. General "Law of Definite Proportions." Chemical reactions always involved fixed proportions, supported the diea of atoms.
        3. Noticed that running a current through water gave off twice as much hydrogen as oxygen, assumed (correctly) that this was because of the number of atoms of each; water had two atoms of hydrogen for every atom of oxygen. But oxygen weighed more, so oxygen atoms weighed more than hydrogen atoms. In this way, worked out the atomic compositions of many chemicals, and the relative weights of atoms., without ever detecting an atom directly.
      3. Ludwig Boltzmann, end of 19th century. Physicist had never accepted idea of atoms, did not believe in them. Boltzmann, a physicist, was one of the first. Worked out Newtonian mechanics for a gas of atoms and molecules - Statistical Mechanics, together with J. Willard Gibbs. Found that it gave the same results as Thermodynamics, but also explained how those results came about. But physicists sharply rejected these ideas, and this may have contributed to Boltzmann's suicide in 1906. But now Boltzmann is honored as a pioneer, ideas are very important, although significantly modified by Quantum Mechanics.
    2. Global warming from the early elements C, H, O, N.
      1. Fossil fuels are C and H, air is O and N. C and 2 O's combine to give CO2, carbon dioxide, H and O combine to give H2O, water. Everything else, such as N and O forming NO2, is a poison or severely degrades the environment. But CO2 is a greenhouse gas, traps heat in atmosphere, warms up the earth. Sunlight and heat radiation (infrared) are both electromagnetic radiation, but light can penetrate the atmosphere, while infrared (given off by warm objects) cannot, and gets reflected back to earth.
      2. Facts:
        1. CO2 will do this.
        2. The earth is warming.
        3. Strong scientific consensus that man-made CO2 is causing the warming. There is a serious question about how much heating is going on.
      3. If second and third world industrialize to our level (and it is their announced intention to do this, and our announced intention to help them do it), then levels of CO2 will rise to six times current levels.
      4. We know enough about the physical world to know that significant warming will occur.
      5. We do not know enough about biological world to predict what the effects will be, but there will be many.
      6. Also, we do not know enough about our society, including our economy, to predict what those effects will be.
  6. Video - Newton's Laws; The Apple and the Moon.
  7. Lab X on circular motion.
    1. Formula. a = v2/r. F = ma so F = mv2/r for circular motion. Cornering. angular velocity w = v/r, so a = w2r, F = mw2r
    2. Perihelion of Mercury
    3. No springs, no standard stretches, just swing the weights. Do this outside or in the corridor. Make sure the knots are tight , the strings tight around the bottle necks, and hold tightly, your fellow students will have to make the observations.