Atoms and Stars
IST 2420
and IST 1990
http://www.is.wayne.edu/drbowen/aasW05
Class 12: April 6
Turning Work In
• All essays on diskettes
• Lab reports due the week after the lab
session
• Making up a Lab session:
o
Get a photocopy of a handwritten data sheet
only from someone in your group – FAX OK
• Put that person’s name on the copy of the data sheet
o
Write your own report on the basis of that data
sheet.
• Credit for turning in someone else’s work?????
4/6/05
Atoms and Stars, Class 12
2
Lab Reports
• Lab Reports that have only a data sheet get
a grade of “D.”
• Lab Reports without an original data sheet
get a maximum grade of “C”
4/6/05
Atoms and Stars, Class 12
3
Status of Newton’s Three Laws
• Range of authority for Newton’s Laws:
Objects moving slower than about three million
miles per hour
o Objects weighing more than about
0.000,000,000,000,000,000,01 pounds (19 zeroes)
o Objects weighing less that about (31 zeroes)
40,000,000,000,000,000,000,000,000,000,000 lb
o
• Within this range of authority, Newton’s Laws
are extremely reliable precise
4/6/05
Atoms and Stars, Class 12
4
Status of Newton’s Three Laws
• Newton’s Laws have passed stringent tests
Predicting mass and orbit of Neptune and Pluto
from their effect on the orbit of Uranus
o Control of spacecraft
o Use in design and control of countless machines
o
• For very small masses (molecular), Quantum
Mechanics is needed instead
• For very large and/or fast objects, Relativity
is needed instead
4/6/05
Atoms and Stars, Class 12
5
Retrograde Motion
http://jove.geol.niu.edu/faculty/stoddard/JAVA/ptolemy.html
http://jove.geol.niu.edu/faculty/stoddard/JAVA/ptolemy.html
• Motion is relative to “the fixed stars” – the
signs of the zodiac, in the plane of our
Galaxy (the Milky Way)
http://cassfos02.ucsd.edu/public/tutorial/MW.html
http://cassfos02.ucsd.edu/public/tutorial/MW.html
• The Milky Way
4/6/05
Atoms and Stars, Class 12
6
Expanding Circles
Review:
• Greek and later science developed isolated
areas of knowledge
Air and water pressure
o Speed of light
o Falling and sliding objects
o Motions of the planets and stars
o
• Areas expanded and met (Newton)
o
4/6/05
Improved each area, plus a bonus
Atoms and Stars, Class 12
7
Expanding Circles
New example:
• Greeks : Electricity and magnetism
separate
o
o
•
Electricity: static electricity
Magnetism: compasses
1775 – 1890 they became practical
o
o
o
4/6/05
Electric (E) and Magnetic (B) fields
Generators, motors, some E-B interaction
Volta, Ampere, Ohm, Joule, Hertz (and our
own Benjamin Franklin)
Atoms and Stars, Class 12
8
Expanding Circles
• 1865 James Clerk Maxwell wrote equations
for electricity and magnetism
• Noticing that the laws as known then said
that a changing B could produce an E but
not the reverse, Maxwell boldly added a
term so that a changing E could produce a B
• Then a changing E could produce a
changing B which produced an E again
4/6/05
Atoms and Stars, Class 12
9
Expanding Circles
•
(0 & 0 previously known)
• But the equation of a wave was known to be:
• So electricity and magnetism must coexist in
waves with speed
= 186,000 miles per second
4/6/05
Atoms and Stars, Class 12
10
Expanding Circles
• Maxwell confirmed in all respects
• In other words, we now know that light was
electromagnetic waves
Thomas Young had shown light to be waves in
1801, not particles as Newton had said
o Speed known since Roemer in 1676
o
• Maxwell (a) hypothesized complete laws
for electricity and magnetism (b) showed
what light was
4/6/05
Atoms and Stars, Class 12
11
Expanding Circles
•
One more example of expanding circles
coming next week
One more theoretical effect: as scientific
knowledge expanded to encompass most
areas, science and technology overlapped
more, especially during and after WWII
•
o
o
4/6/05
Technology now driven by science
nuclear energy (both military and civilian),
radio & TV, lasers, transistors, computers,
digital chips and microprocessors, the Internet
Atoms and Stars, Class 12
12
Readings
Jacob Bronowksi, Knowledge or Certainty
• Absolute certainty is impossible in science
Looking at an object with infrared, then visible,
then x-rays should yield greater detail. Infrared
is very blurry, visible is pretty good, but x-rays
are too high energy to be focused. Perfect detail
of “God’s-eye” view is impossible
o Statistical uncertainty in measurements - Gauss
o
4/6/05
Atoms and Stars, Class 12
13
Knowledge or Certainty
• 1795
• Science is discussion and argument
preceding knowledge
• Also Uncertainty Principal 1927 Werner
Heisenberg – cannot locate particle exactly
4/6/05
Atoms and Stars, Class 12
14
Knowledge or Certainty
• No practical
effect at
macroscopic level, but a philosophical
problem with The Mechanical Universe and
with “The God’s eye view”
• But certainty leads to tragedy – Nazis
• (DB) Certainty and power combined
4/6/05
Atoms and Stars, Class 12
15
Readings
Moti Nissani, What Is Science?
• Difficult or impossible to give a dictionarytype definition for science
• (DB) Working scientists rarely think about
the history or philosophy of science
• Start with philosophy of Thales – free
inquiry
4/6/05
Atoms and Stars, Class 12
16
What Is Science?
• Then hypothesis and experiment (Torricelli)
• Falsifiability – reason and logic are not
sufficient to discover truth
But contradiction by experiment does not
always mean rejection of hypothesis – can lead
to reexamination of experiment or modification
of hypothesis
o Scientists “on the trail” have personal concerns
o
4/6/05
Atoms and Stars, Class 12
17
What Is Science?
o
Scientists “on the trail” have personal concerns
• Argument and community lead to progress
o
Semmelweiss and deaths in maternity ward
•
•
•
•
•
•
4/6/05
Neighboring ward far safer
Did priest’s visit scare patients?
Washing hands – doctors did dissections beforehand
This fixed the problem
Profession slow to accept this change
Even scientists can be closed-minded, resist change
Atoms and Stars, Class 12
18
What Is Science?
• Theories unify many hypotheses and
experiments
o
Price is often inaccessibility to non-scientists
• Scientists usually not concerned with these
issues or with philosophical uncertainty
• Science many not be perfect, but it can still
be very good
• Many use technology but not the scientific
foundation
4/6/05
Atoms and Stars, Class 12
19
Common Writing Problems
• Functional grammar
o
o
o
o
o
o
4/6/05
Rules of grammar have a purpose – to transmit
meaning
Rules of grammar are always changing
Different grammars for different groups
Get too far from the group’s grammar and you
are not understood (must change with changes)
The further you get from the group’s grammar,
the harder it is to understand you
Being able to use good standard grammar is
like dressing well for a job interview
Atoms and Stars, Class 12
20
#1 Reason for Writing
• To organize your own thinking
#1 Way to Good Writing
• Have something you want to say
More Examples and Details
• www.is.wayne.edu/olgt or The Everyday Writer
4/6/05
Atoms and Stars, Class 12
21
Organization
• Many possibilities for organization
Historical
o Logical
o Specific to general, or general to specific
o Combination
o
• Signal transitions from one topic to another
o
4/6/05
Paragraphs help here
Atoms and Stars, Class 12
22
Quick-and-Easy Organization
• Write body first
• One you have figured out what you are
going to say (the Body), write the
Introduction and Conclusion afterwards
• Body should have general statements and
specific examples and quotes
4/6/05
Atoms and Stars, Class 12
23
Sentences
• A sentence:
Verb (easiest to find - action)
o Subject (did the action)
o Complete thought
o (starts with capital, period at end)
o
• (Y/N) Because he hit the ball.
• (Y/N) John hit the ball.
4/6/05
Atoms and Stars, Class 12
24
Sentences
• Is it a sentence? Consider it all by itself.
• Common sentence problem #1:
o
Sentence fragment – something that starts with
a capital and ends with a period but is not a
sentence
• Because he hit the ball. John ran to first base.
• Fix by joining to main thought with a comma (,)
– Because he hit the ball, John ran to first base.
4/6/05
Atoms and Stars, Class 12
25
Sentences
• Is it a sentence? Consider it all by itself.
• Common sentence problem #2:
o
Run-on sentence – two or more sentences
written as one
• John hit the ball he ran to first base.
• Fix by breaking into two sentences
– John hit the ball. He ran to first base.
• Or by joining with semicolon (;) to show causality
– John hit the ball; he ran to first base
4/6/05
Atoms and Stars, Class 12
26
Number (singular/plural)
• Both subject and verb have number
o
If these are not the same, signals conflict
• Members join the club
• A member joins the club
• “One s”
• Without a reason, do not change number
from sentence to sentence
o
4/6/05
(Bad) People should take care of their health.
You should take your vitamins.
Atoms and Stars, Class 12
27
Tense (past, present, future)
• Without a reason, do not change tense from
sentence to sentence
Citations
• “Scientific investigation is not, as many
people seem to suppose, some kind of
modern black art.” (Huxley, 1)
• Cite the source even if you are paraphrasing
o
4/6/05
Ideas: very important in academia, trace them
Atoms and Stars, Class 12
28
Punctuation
• Apostrophe (‘)
o
o
Contraction
Possession (‘s or s’)
• Some words inherently possessive, no ‘ (e.g. theirs)
o
Never for pluralization (in 1600s, not in 1600’s)
• Lists
Separate list items with commas (last one is
optional)
o If any list has a comma inside an item, separate
items with semicolon
o List can be singular even if many members
o
• This group of authors travels by bus.
4/6/05
Atoms and Stars, Class 12
29
Wrong Word
• Some words are commonly confused –
memorize or use list or dictionary
o
o
o
o
o
o
4/6/05
its Vs it’s
whose Vs who’s
their Vs there
too Vs to
accept Vs except
Many, many more
Atoms and Stars, Class 12
30
Last Week - Lab 10
• Measure focal length in mm
o
4/6/05
Measuring focal length
for reducing lens
Atoms and Stars, Class 12
31
Lab 10A – Telescope
• Tonight, Lab 10, Exercise III:
Two lenses are objective (closer to object) and
eyepiece
o Good telescope – focal length for objective is
f obj
longer than for eyepiece o
M 
o
f eye
Good idea to make screen for objective: cut
hole in card, slightly smaller than lens, tape lens
to card, bend card to stand lens up
• Do not do the WRITING ASSIGNMENT
4/6/05
Atoms and Stars, Class 12
32
For Next Week
• Reader: 61 – 73 (emails concerning the
connection between astronomy and
evolution)
• Lab Manual: Experiment 11, Pp 64 - 77 on
Centripetal Forces and Gravitational
Motions
• Turn in Lab 10A report
4/6/05
Atoms and Stars, Class 12
33
Future Due Dates
• Essay 2 due April 13
o
The Everyday Writer (DIS standard) and
writing web site http://www.is.wayne.edu/olgt,
link to Writing Guide
• Last regular class April 20
o
Work turned in after this date may not be
included in regular grade
• April 27 Final Exam (NOT April 23)
4/6/05
Atoms and Stars, Class 12
34
IST 1990
• Essays based on set questions, taking
readings into account
Get a set from me
o Tell me which question you are answering,
before title
o
4/6/05
Atoms and Stars, Class 12
35
End
Lab starts now, for everyone!