GST 2420: Atoms and Stars
An Historical Introduction to Astronomy, Physics, and Scientific Discovery.
Fall 2002, Section 983, Call Number 16050
Agenda 13 for 12/4

  1. Announcements:
    1. Final is in two weeks, on 12/18. Next week is the last regular class.
    2. Lab tonight is V. Next week is VI. There will be time in class next week to complete the writeup for that lab, so that you will have only the Final to worry about during the week before the Final.
    3. Student Evaluation of Teaching (SET) tonight.
    4. I have some ISP course schedules with me. The WSU office has some of the full schedules.
    5. Course web site: http://www.cll.wayne.edu/isp/drbowen/aasf02 (also links from Pipeline).
    6. Online Life at WSU with links at http://www.cll.wayne.edu/isp/drbowen/OnlineLife.
    7. Online grade reports are working. To enable yours, give me a password on the small slips of paper provided. Go to the course web site (see B above) to get an online grade report.
      1. There may be glitches with the University online grade reporting system (yes, it COULD happen, unlikely as it may seem). In the past, employers have accepted printouts of the above type of course grade report.
      2. I will update these reports to show the GST 1990 postings to the ListServ.
    8. The State of Michigan will be cutting its budget to meet a shortfall. Almost all of the cut is expected to come from Higher Education (this will be announced tomorrow, 12/5). This may result in canceling more classes than would normally be the case. If this occurs, we will try to keep the ISP course listing on the ISP web site up to date, and this may be the most up-to-date listing available, in the event of a large number of late changes. For this listing, go to www.isp.cll.wayne.edu/isp, click on the "COURSES" button and then on the link "Courses Offered Winter 2003." You may also want to keep in touch with DIS/ISP Student Services at 313-577-0832.
  2. Set up demonstration of diffusion of food dye in water.
  3. Discussion of Lab XI - swinging bottles.
    1. Centripetal force is on the bottle, inward towards the center of the circle, exerted by the swinger on the bottle. The centrifugal force is exerted by the bottle on the swinger and is outward away from the center (swinger has to pull inwards to counter it). By Newton's third law (action = reaction but in opposite direction) these are equal in size but opposite in direction.
    2. The string experiences both forces, on opposite ends.
      centrifugal <======== string ========> centripetal
      (Remember that Newton's Third Law of action and reaction says that the string is also exerting as well as experiencing forces. The string is how the centripetal force gets transmitted from the swinger to the bottle, and how the centrifugal force gets transmitted from the bottle to the swinger.)
    3. Force on bottle to keep it in circle: F = ma and a = v2/r, so F = mv2/r, and force is affected by m, v, and r. If the force is smaller than required, the mass moves outwards (large r is smaller force), while if the force is greater, the mass moves inwards (smaller r is larger force).
      1. In a fraction, if the numerator (top) gets larger, the fraction gets larger, while if the denominator (bottom) gets larger, the fraction gets smaller. Increasing m and/or v increases the force, while increasing r decreases the force. If more than one of these is changing, then their relative impacts determine whether the force increases or decreases. Since v is squared, it has roughly twice the impact of m and r.
        What happens to the fraction? gets bigger then gets smaller then Overall
        If the numerator (top) Fraction gets bigger Fraction gets smaller What you expect
        If the denominator (bottom) Fraction gets smaller Fraction gets bigger The opposite
      2. Example. What happens to the value of a fraction as the numerator (top) and denominator (bottom) change?
        Action Original = 100/20 ­100 to 200 (200/20) ­20 to 50 (100/50) ¯100 to 50 (50/20) ¯20 to 10 (100/10)
        Value of fraction 5 10
        (bigger)        		 2
        (smaller)        		 2.5 (smaller) 10
        (bigger)
    4. Swinging pendulum - force diagram

      The upwards component of the force exerted by the string cancels the downward gravitational force, leaving the uncancelled part of the force exerted by the string as the centripetal (inward) force to keep the mass moving in a circle. Since there is no net upwards or downwards force, the mass moves in a level plane.
  4. Interim observation of food dye diffusion. Density gradient.
  5. 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. Draft of info sheet for Final (handout)
    3. Continue review.
  6. SET
  7. Discussion of reading
    1. What exactly was decided?
    2. Decision reversed by election of new candidates for School Board on August 1 2000, one year after the initial decision
  8. Colliding circles of knowledge, relationship between science and technology
    1. Hierarchies of knowledge. We can arrange knowledge in levels, say by the complexity of the subject system, perhaps in terms of the number of elementary particles involved. Other schemes are possible, and no such scheme is entirely satisfactory (the one here does not include the , but this one would go, starting from the bottom:
      1. Humankind, including the past
      2. Society
      3. Family
      4. Individual human being
      5. Living beings (plants and animals)
      6. Organs
      7. Tissues
      8. Living cells
      9. Larger molecules
      10. Smaller molecules
      11. Atoms
      12. Elementary particles, such as electron, proton and nuetron and the one from my Ph.D. thesis, the K meson
      13. Sub-elementary particles such as the quark, the parton and the gluon

      Here is the point - we know a very great deal about the lower-middle middle levels, 9 through 11, and less as we move away from here, either up or down. In these lower-middle levels, the expanding circles of knowledge have expanded to cover everything, or at least almost everything.

      So? It has been said more than once in this course that, prior to the twentieth century, technology normally drove science (science rarely was the basis for new technologies, while technology often was the basis for new science [witness Torricelli]), while during the twentieth century the two became more even. I believe that it has even reversed, and that new technologies are now based on science. Many of the core technologies of the twentieth century were in fact predicted on the basis of science at least ten years before they were developed (nuclear energy whether military or civilian, lasers, computers, digital chips and microprocessors, the Internet, and so forth). Why now? Perhaps because the expanding circles expanded to fill almost all of the space.

    2. Will science continue as it has?
      1. Less interest in school
      2. Religious fundamentalism - moves towards creationism or intelligent design continue
      3. Increasing interest in mystical thought
      4. Decreasing government funding - can science be science in a proprietary setting?
      5. Increasing (?) post-modernist attacks on science as just another belief system
      6. Possible limitation of science to industrial society, while we are moving beyond industrial society
      7. etc.
    3. Will there be consequences if science does not continue as it has? Some possibile consequences: US leadership, economic, progress
  9. 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 act as a greenhouse gas. (Interesting aside. Everybody assumes that H2O is benign, but clouds do have a warming effect.)
      2. The earth is warming.
      3. We are putting enough CO2 into the atmosphere to have an effect.
      4. 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. Can we let it happen and adapt? My take on this.
      1. We know enough about the physical world to know that significant warming will occur.
      2. We do not know enough about biological world to predict what the effects will be, but there will be many.
      3. Also, we do not know enough about our society, including our economy, to predict what those effects will be.
      4. Therefore, we cannot make a rational decision about this, since we do not know how much it will cost to adapt.
  10. Food dye diffusing in water. Modern explanation.
  11. Lab V, pages 16 - 20.