4/12/06 Atoms and Stars, Class 13 1

Atoms and StarsIST 2420

and IST 1990

Class 13Winter 2006

Instructor: David BowenCourse web site: www.is.wayne.edu/drbowen/aasw06IST 1990 Moodle: techtools.culma.wayne.edu/moodle

My new cell-phone number: 248-376-9848

(the number to call during 5 – 6 PM office hours)

4/12/06 Atoms and Stars, Class 13 2

Agenda

• Assignments, passbacks, initial signin sheet• Pick up:

o Notes for Class 13o Final Where-Is

• Upcoming assignmentso Windows Calculator for Final

• Review of readings• Emphasizing main points one more time• Updates: natural disasters & bird flu• Lab 11: The Orbiting Bottle

4/12/06 Atoms and Stars, Class 13 3

Changes in Lab Schedule

• Changes to Syllabus lab schedule: o Lab 11 tonighto We will not do Lab 4 (we went over the content

last class)

4/12/06 Atoms and Stars, Class 13 4

Upcoming …

• April 19 (last regular class)o Essay 2 dueo Review for Final Exam

• April 26: nothing that night but the Final Exam

• Opportunities for extra help:o 5 – 6 PM next week (April 19)o Review Session next week during classo 5 – 6 PM before Final (April 26)o Telephone, email, set up a time

4/12/06 Atoms and Stars, Class 13 5

Semester is Ending!

• If you have been relying on being able to turn work in late, it is time to get goingo Alternatives: D, E, I, X, drop – see counselor!

• Getting ready for Final:o Read Information Sheet carefully – a lot of

information thereo Look at Final Topics carefullyo Use Review Session!

• Final Where-Is probably April 12

4/12/06 Atoms and Stars, Class 13 6

16ths on the Final

• Options for doing the math for converting 16ths (inches, ounces) to decimal (inches, pounds)o Windows calculatoro Lab calculator (I will pass from person to

person)

4/12/06 Atoms and Stars, Class 13 7

Windows Calculator

• Start Programs Accessories Calculator• If it looks very different,

click View Standard• Click on keys or use

Keypad or Numeric Keypad on right of keyboardo Make sure Num Lock

is lit before using NumericKeypad

4/12/06 Atoms and Stars, Class 13 8

Experiment 11• Most reports did say that the formula for the

ellipse was trusted more than the experimental measuremento The power of authorityo Also, not trusting your techniqueso But in this case, the authority was not trustworthy

• Many said no use in repeating measurementso Results would be the same

• No! Every technique has a limit, will have variations when you push that limit

• It is never easy, but scientists will eventually come down on the side of experiment

4/12/06 Atoms and Stars, Class 13 9

Experiment 7

• Should find V of block V of displaced water (Archimedes was correct)o Can be large error because of small height of

displaced water• Should find S.G of wood % below water

o Large error in estimating % below water• Dumbbell – should find

W in air W in water + W displaced watero Errors were larger than I thought, may be a

problem

4/12/06 Atoms and Stars, Class 13 10

Later Evidence for Atoms (Q10d)

• 1895 Boltzmann and Gibbs with Statistical Mechanics – success of Atomic Theory

• But Atoms still seen as perhaps just a theoretical convenience, perhaps no actual existence

• 1905 Einstein analyzed Brownian motion to find density of atomso Experimentally confirmedo More convincing

4/12/06 Atoms and Stars, Class 13 11

Later Evidence for Atoms (Q10d)

• 1911, Rutherford discovered electron and nucleus, components of atomso Atomic Theory adoptedo But atoms are not elemental (they have parts),

even though atoms are still called elements• Similar definitive evidence since then• Individual atoms seen in 1970s (~)

4/12/06 Atoms and Stars, Class 13 12

Readings – Big Bang

Emails on Big Bang• #1 from George Gale (1999)

o Kansas school board rejected Big Bang and radioactive dating along with evolution

o “Young earth creationists” – 6,000 years in past for age of earth Vs 4.5 billion years from radioactive dating (Q14)

o (DB) 6,000 years ago is a reasonable scientific date for writing and the development of records

4/12/06 Atoms and Stars, Class 13 13

Evidence for Big Bang

• #2, Neil De Grasse Tysono “Theories” instead of “Laws” – humble nowo 1929 Edwin Hubble, galaxies receding, further

galaxies receding fastero Gravitational lenses – focused object receding

faster than focusing object (further away)o “Time dilation” from Einstein’s Special Theory

of Relativity – time slows down if motion faster

4/12/06 Atoms and Stars, Class 13 14

Evidence for Big Bango “Time dilation” from Einstein’s Special Theory

of Relativity – time slows down if motion faster• Distant supernovae do explode and age more slowly

compared to near ones (Big Bang says moving faster)o Cosmic Microwave Background predicted ,

discovered 1965• A peak location and spectrum (shape of intensity Vs

wavelength) that matches measurements• Has a distant source – we see it heated when passes

through matter

4/12/06 Atoms and Stars, Class 13 15

Evidence for Big Bang

o Cosmic Microwave Background predicted , discovered 1965 (cont’d)

• Molecular “thermometers” show background radiation hotter from distant (older) galaxies

o Also consistent with mix of atomic species• Consistent with accelerator laboratory experiments

o But background radiation too uniform• “Inflationary universe” explains this, and more• (DB: some non-uniformity observed this year)

4/12/06 Atoms and Stars, Class 13 16

Evidence for Big Bango But required mass is missing

• (DB: dark matter is being discovered – see update)

• #3: Gregg Esterbrooko Modern science chance-based, seems not to

require God, also predicts death of the universeo 1999 conference at Berkeley CA

• Astronomer Allan Sandage: majesty of Big Bang helped make him a believer

• Ian Barbour: physical law seems to favor life (Anthropic Principle)

4/12/06 Atoms and Stars, Class 13 17

Evidence for Big Bang• #3: Gregg Esterbrook (cont’d)

o Consilience by E.O.Wilson: can reconcile technical and spiritual, along with other books

o Creation “ex nihilo” consistent with latest Big Bang theories

o (Q14) Parallel between God creating existence from “waters” with H being most abundant element

• (DB) Water necessary for life (at least life like us), life on earth did come from life in water

o “Existence may be … prewired … for life”o If we came late, still may be early in time span

of universe

4/12/06 Atoms and Stars, Class 13 18

Evidence for Big Bang

• #4: Thomas Dianao More and more can be explained without the

action of Godo Ancients had gods, each with own areao Geocentric theory – we were at center of

universeo Now we are displaced from central positiono Quantum Mechanics lets Big Bang be created

from empty space (quantum fluctuations)

4/12/06 Atoms and Stars, Class 13 19

Evidence for Big Bang

• #4: Thomas Diana (cont’d)o At one point, science said life impossible

without extraordinary coincidences in physical constants (Anthropic Principle)

• Now inflationary theory of universe makes this less necessary

o How to retain belief? (Q14)• Not a belief in anthropomorphic God, but one that

transcends as science transcends the ordinary• Scientific mastery of universe results in separation

4/12/06 Atoms and Stars, Class 13 20

Evidence for Big Bang• #4: Thomas Diana (cont’d)

o How to retain belief? (Q14)• Scientific mastery of universe results in separation• Separation has led some to seek immanent God

– “immanent” (Theology): present throughout the universe, as opposed to transcendent (existing apart from the universe)

• We can achieve this – experience power greater than ourselves

– Rituals– Gazing at starlit sky – experience not diminished by

knowledge

4/12/06 Atoms and Stars, Class 13 21

The Big Bang…

Big Bang, expansion of universe• 3-D analogy to a rising loaf of raisin bread

o Expansion with no center (but this bread has edges, unlike the universe)

o http://www.is.wayne.edu/drbowen/aasw05/BigBangAnalogies.htm

• 2-D analogy to the surface of an expanding balloono http://www.astro.ucla.edu/~wright/Balloon2.html

4/12/06 Atoms and Stars, Class 13 22

The Big Bang…

Big Bang, expansion of universe

• 3-D analogy to a rising loaf of raisin breado Expansion with no

center (but this bread has edges, unlike the universe)

4/12/06 Atoms and Stars, Class 13 23

The Big Bang…

• 2-D analogy to the surface of an expanding balloono No edge but cannot go off

the balloon surface• (DB) (Q14) Universe

originally light, no mattero Had to cool off for matter to

exist

4/12/06 Atoms and Stars, Class 13 24

Brain Candy…Wormhole• A theoretical possibility within Einstein’s

General Theory of Relativity (1916)o A shortcut through 4-D space-time that could

dramatically speed travel between points connected by the wormhole, and into the future

o Requires an undiscovered form of exotic matter with negative energy density – a “white hole,” contrasts with a black hole

o Wormhole could collapse on the traveler• http://en.wikipedia.org/wiki/Wormhole

4/12/06 Atoms and Stars, Class 13 25

Wormhole

From Wikipedia (see link on previous slide)

4/12/06 Atoms and Stars, Class 13 26

Update• Inflation: Universe

expanded “exceeding quick” in first trillionth of a second, to size of grapefruit• Produces “Anthropic

Principle”• Now expansion of

universe is acceleratingo Einstein’s

cosmological constant

4/12/06 Atoms and Stars, Class 13 27

Readings: Black Holes (Hewitt) (Q3)

• Black hole: escape velocity at surface > speed of light, so cannot escape (Black Hole is dark)o Space collapses nearby, draws in anything nearby

• DB: can see light as indrawn objects are destroyedo Can also be seen by gravitational effect on neighborso DB: Burned-out star collapses, forms Black Hole

• Nuclear fuel burns out, star collapses• Black Hole can draw in other matter

• Theoretically possible for reappearance of this matter as white hole, but this is unknown

4/12/06 Atoms and Stars, Class 13 28

Readings: Global Warming (Q12)

• Light comes in to earth from suno Some absorbed on surface, warming eartho Rest reflected, exits to spaceo Greenhouse gases in upper atmosphere trap

reflected light, some returned and further heats earth

• Amount of warming now about 1ºF but projected to rise rapidlyo By 2100, projections = 2.5ºF to 10.4ºF

4/12/06 Atoms and Stars, Class 13 29

Atmosphere, Climate and Change by Thomas Graedel and Paul Crutzen, Scientific American Library, 1997.

4/12/06 Atoms and Stars, Class 13 30New York Times, “Computers Add Sophistication, but Don’t Resolve Climate Debate,” Science Times Pg D3 8/31/04

4/12/06 Atoms and Stars, Class 13 31

Global Warming (cont’d)

• Largest effect in Antarctico Snow reflects most,

sea water leasto Arctic ice

disappearingo Polar bears in dangero Eskimos suing US The New Yorker, cover, 12/12/05

4/12/06 Atoms and Stars, Class 13 32

Global Warming (cont’d)

• What to do? Options:o Nothing. Live with it. (Physical and ecosystem

consequences not known)• Humans can adapt quickly, natural world cannot –

evolution is slow, but humans are free of evolutiono Cosmetic actions. Cite uncertainty, call for

more research• Will never have 100% certainty

• Options:o “Invisible hand” of market

• Trade CO2 permits

4/12/06 Atoms and Stars, Class 13 33

Global Warming (cont’d)

• Options (cont’d):o Limit CO2 production

• Increase energy efficiency, use waste energy, switch to low-carbon fuels (natural gas) away from coal and petroleum

o Remove CO2 once it is generated• Sequestration – pressurized underground or under

deep ocean• (DB) Recent poll says US thinks scientists

are confused about Global Warming. NOT!o Deliberate confusion caused by industry groups

opposed to controls – citing 2 or 3 out of 2,500

4/12/06 Atoms and Stars, Class 13 34

Readings: Icecaps and Hurricanes

Evidence for Global Warming:• Thawing icecaps• Coral bleaching• Hurricanes• Melting glaciers• Desertification• Rising sea levels

4/12/06 Atoms and Stars, Class 13 35

DB: That’s not all…

• Many worldwide resource issues – “the human footprint”o Water (drinking, irrigation, industrial), food,

farmland, population (6 billion 9 billion), living in unsafe places, petroleum, trash, development

• Managing the human footprint will be a major, continuing issue

4/12/06 Atoms and Stars, Class 13 36

Re-emphasizing Main Points

• Two pillars of scienceo Experiment: makes science reliable

• Scientists led astray by logic (Aristotle) and belief (Inquisition)

• Experiments base science on direct experienceo Theory: makes science valuable

• Once you have a reliable theory, it tells you the answer in advance, can use it as technology

• Two quotes from Copi, Reader Pg 8

4/12/06 Atoms and Stars, Class 13 37

Re-emphasizing Main Points

• I want experiments in course to:o Give you direct experienceo Illustrate experiments in classo Illustrate social nature of science within the lab

groups

4/12/06 Atoms and Stars, Class 13 38

Updates

• Bird flu:o Some concern over transmission via domestic

pets in rich countries• Natural disasters:

o Hurricane season of 2005: with better measurements, more hurricanes

o In addition to hurricanes, warm Gulf of Mexico also important in tornado formation

• Tornadoes generated when warm air from Gulf meets cold air from Northwest

4/12/06 Atoms and Stars, Class 13 39

Updates (cont’d)

• Plate tectonics:o Determines location of mineral resources and

fossil fuels• Mineral resources brought near surface by old zones

of rising magma• Fossil fuels generated when organic matter covered

over before it rots, “cooked” when drawn down to warmer depths (but not hot – like baking a turkey) then brought back near surface so we can find it

– Temperatures increase going down into the earth• Plate tectonics does both of these

4/12/06 Atoms and Stars, Class 13 40

Updates (cont’d)• Tenth planet?

o In Class 5, mentioned “tenth planet” 2003 UB313 nicknamed “Xena,” larger than Pluto

o That size based on inference from brightnesso New direct measurement says Xena about the

same size as Plutoo Inference from brightness fooled because Xena

is highly reflectiveo Now, Pluto and Xena will probably be accepted

as planets or demoted, as a pairo Meaning of “planet” still being debated

4/12/06 Atoms and Stars, Class 13 41

Uncertainty Principle (Repeat)

• No practicaleffect atmacroscopic levelo A philosophical problem with The Mechanical

Universe and with “The God’s eye view” or The Clockwork Universe over age of universe

• Important at atomic and molecular levelo Uncertainties are large on atomic scaleo What underlies our reality is strange

4/12/06 Atoms and Stars, Class 13 42

Lab 11: Orbiting Bottle• Swing bottle on string

o Measure distance from finger to middle of water, convert to decimal feet (÷ inches by 12)

o Measure weight of bottle, convert to decimal pounds

o Time ten “orbits” or circles (count from zero!)o Measure angle down from horizontalo Use formulae

• Large hand motion to get bottle moving, then small hand motions to sustain motion during measurements

4/12/06 Atoms and Stars, Class 13 43

Orbiting Bottle

• String pulls in two directions, H and V

• Two formulae for FH

1. FV (up) balances W (down), then angle determines FH

2. Inward force to move bottle in circular orbit

• Two should agree, roughly

4/12/06 Atoms and Stars, Class 13 44

SET

• Course information:• Me: David Bowen• Courses:

o IST 2420, Atoms and Stars, 4 Credits, Section 001, CRN 24609

o IST 1990, Science and Religion, 2 or 4 Credits, Section 004, CRN 24607

• Lab afterwards