If this is your first day in class come to the front desk and pick up material including a sheet that must be filled out and returned today.

1

• If this is your first day in class come to the
  front desk and pick up material including a sheet
  that must be filled out and returned today.
• Labs will be passed out in class today. You must
  fill out the first page of the lab sheet before
  coming to lab next week or lose points.
• I have responded to all emails I received up to
  class time.
• If you did not send me an email, please do so a
  soon as possible. (see syllabus)

2

• Chapter one test and review due next Friday (next
  week).
• There is an error on the Ch 1 review, the
  questions are on page 25.
• The multiple choice questions are on page 24 and
  the answers on page 25

3
Review of where you should be

• Read syllabus, ask questions
• Purchase textbook
• Purchase calculator
• Get assignments from web page
• Look at Chapter 1 tests on the web page
• Begin working on Chapter 1 Review
• Begin work of first page of Metric Measurements
  Lab
• Ask questions Friday and Monday
• Send email to gaultj_at_moval.edu

4
Converting units first labText pages 30-33

• English system
• Feet
• Yards
• Miles
• Inches
• Pounds
• Slugs
• Poundals
• seconds

5
Metric system

• Meter length
• Kilogram mass
• Second time
• 1 kilometer 1000 meters kilo
• Kilogram, kilobyte, kilosecond
• 1 centimeter 1/100 meter centi
• 1 millimeter 1/1000 meter milli
• (Know these three for the first test)

6
Going from one system to another (English to
metric)

• 2.54 cm l inch 2.54 cm/in
• 2.21 pounds 1 kilogram 2.21 lbs/kg
• How many cm in 50 inches?
• 50 in x 2.54 cm/in 127 cm
• Be sure the units you dont want in the answer
  (inches in our case) cancel and leave only the
  units we want (cm).

7
Another example

• How many inches in 50 cm?
• In this case the cm cancel and we are left with
  inches in our final answer.

8
Example with feet and inches

• Change 1.78 m to ft and inches.
• Begin by changing 1.78 m to 178 cm.
• Then change the cm to inches
• We now need to change the inches to feet and
  inches.
• 5 ft 5ft x 12 in/ft 60 in
• 70.1 in 5 ft 10.1 inches

9
Complete the first page of your lab before Monday
and ask questions if you have difficulty.

• When you enter the lab on either Tuesday or
  Thursday, the first page of your lab will be
  checked and you will lose points if it is not
  complete.
• You may ask questions in class Friday or Monday
• You may ask me for help with these problems.
• You may get help in the learning center.

10
Physical Science

• Chapter 1
• What is Science?
• How did our ideas about our Solar System Develop?

11
How can we explain the way the sky looks, how it
changes?

• The way the sun moves
• Every day
• Changes over the course of the year
• The way the moon moves
• Every day
• Over the monthly cycle
• The stars
• Every night
• Over the course of the year
• The planets (moving stars)

12
How do the stars and moon move across the sky at
night?
13
Early Ideas about the Solar System, what makes
things move

• The gods (or spirits) control their movement
• Greeks (Hipparchus) had a theory that the sun,
  moon and stars moved around the earth
• Ptolemy of Alexandria (A.D. 150) developed these
  ideas into a mathematical model.
• Science works by one person modifying the ideas
  of another.

14
Ptolemaic model
STARS
Saturn
Earth
moon
Venus
Mars
Mercury
sun
Jupiter
stars
15
Ptolemaic Model

• Based on circles
• Geometry was the basis of all nature
• A pure idea, the real world was secondary
• Earth was at the center Stationary
• Sun, moon and planets moved around the Earth
• Orbit times were determined by cycles
• Epicycles were necessary for the planets' motions
  to be correct (in the entire model there were 80
  cycles and epicycles)
• Stars were on a large sphere that rotated around
  the Earth.

16
Successes of the Ptolemaic model

• Explained the motions of the heavenly bodies
• Allowed prediction as to where the planets would
  be, when eclipses would occur, etc
• First model to allow mathematical calculation
• You could calculate where the planets would be a
  year from next June. How the sky would look.
• Important for astrological calculations
• Lasted for 1400 years

17
Problems with the Ptolemaic model

• Difficult to use (to do the calculations)
• Over large periods of time, it was seen to give
  the wrong answers.

18
How can we know that the Earth is moving and not
the sun?

• You have 5 min to form a group of 3-6 people with
  those around you.
• Write your names on a sheet of paper and write on
  it your best suggestion for knowing that it is
  the Earth that is moving and not the sun and the
  stars.
• There are 5 bonus points people in groups that
  get it right.
• Use ideas that were available before telescopes,
  space shuttles, etc.

19
Nicolaus Copernicus (1473-1543) Studied Law and
Medicine Observed the moon eclipse a star Held
many offices in the church
20
Nicolaus Copernicus (1543)

• Sun was at the center of the solar system
• Earth (and other planets) moved in circles about
  the sun
• Earth spins
• Moon circles the Earth.
• Stars are far away
• This means the Earth is
• no longer at the center
• of the Universe!

21
Copernican model of the solar system
STARS
moon
Earth
sun
Mercury
Venus
Jupiter
Mars
Saturn
22
The Copernican model

• Still depended on circles
• Did away the the epicycles
• Was easier to use than Ptolemys
• Did not give any more accurate results than
  Ptolemys
• Had little effect on people in general but was a
  catalyst for future development
• He broke part of the old prejudices
• Earth standing still
• Earth at the center of the Universe

23
Tycho de Brahe (1600)

• Born to a rich Danish family
• Kidnapped by Uncle
• Uncle dies saving the King
• Tycho becomes a spoiled rich brat.
• Nose cut off in fight

24
Tycho de Brahe (cont)

• Sees eclipse and nova (new star)
• Appointed Royal Mathematician
• Given Haven
• Given generous financial support
• Makes accurate measurements of stars and
  planets positions
• Makes measurements often

25
Tycho de Brahe (cont)

• Did not have telescope
• Measured to 1/100 of a degree
• Liked parties and liquor
• Died as the result of one such party

26
Johannes Kepler (1620) Modern scientistMedieval
Astrologer
27
Johannes Kepler (1620) Modern scientistMedieval
Astrologer

• Born poor in a family that had once been rich
• Educated in the church (Lutheran)
• Became obsessed with a theory of the location of
  the planets
•  

28
Regular solids
octahedron (8 faces, 6 vertices).
dodecahedron (12 faces and 20 vertices)
an icosahedron (20 faces and 12 vertices)
cube, or hexahedron (6 faces and 8 vertices
tetrahedron (4 faces, 4 vertices).
29
Johannes Kepler

• Writes book about his theory
• Becomes Tycho Brahes assistant
• Brahe dies, Kepler takes his data
• Kepler uses data to prove his theory about the
  planets
• Error of 1/8 of a minute shows Kepler the old
  ideas are wrong

30
Keplers Laws

• Required 30 years of very tedious calculations
• One calculation on the position of Mars required
  90 pages of calculations
• 1) The orbits of the planets are ellipses with
  the sun at a focal point
• 2) The radius vectors of the planets sweep out
  equal areas in equal times
• 3) (Time planet takes to go around sun)2
  (Average distance from sun)3 is the same
  for all the planets

31
Keplers laws

• His approach was more modern than Copernicus.
• Depended on real measurements
• Fit the data exactly (as it was possible to
  measure)
• Broke the old idea that everything could be
  explained with circles.
• Pointed directly toward gravity. (Kepler said
  that two rocks in space would attract each other!)

32
The Telescope

• Telescope invented by lens makers
• Invented 10 years before Kepler died
• Allowed one to see millions more stars
• Showed that moons exist on Jupiter
• Kepler writes the first scientific paper
  explaining how the telescope works

33
Kepler First modern Scientist

• Kepler put the data first, he would not accept a
  theory that did not fit the data
• Ptolemy is known to have selected that data which
  fit his model and thrown away other data
• Progress became more rapid when it was possible
  to question everything including the old
  authorities such as Aristotle
• Are authorities a problem today?

34
Isaac Newton (1642-1727)

• A farmers son who did well in math.
• At age 22 years old, the university (Cambridge)
  was closed for 18 months due to the plague. In
  that 18 months, Newton
• Found the binomial theorem in algebra
• Invented calculus
• Developed a theory of light still in use today

35
Isaac Newton (1642-1727)

• Discovered the universal theory of
  gravitationIf I have seen further than others,
  it is because I have stood on the shoulders of
  giants.
• Especially Kepler
• And Galileo
• Galileo did not develop any new idea about the
  solar system, but he strongly supported the idea
  that the Earth circled the sun and got into
  trouble with the Church for this.
• As Galileo had a telescope he could clearly see
  that the Earth was moving, yet he got into
  trouble for saying this.

36
More about Newton

• Wrote more books about the Bible than about
  science.
• Was in charge of the English mint
• First put the ring around the outside of coins to
  help prevent the figure on the coin from wearing
  off.
• Developed the laws of motion we will study in the
  next chapter
• Had a very difficult personality, suffered from
  depression.

37
Universal Gravitation

• All objects (that have mass) attract all other
  objects that have mass.
• The force of attraction is proportional to the
  masses of the objects
• Double the mass, the force is doubled
• The force is inversely proportional to the square
  of the distance between the objects.
• Double the distance, the force is ¼ as great
• Triple the distance, the force is 1/9 as great

38

• In the history of the development of our ideas
  about the solar system and universal gravitation,
  something happened.
• We (humans) found a new way of knowing.
• The science way (the scientific method)

39
How is science different from other ways we know
things?
40
What are some of the different ways we know
things?

• How do you know what food you like?
• How do you know who is your friend?
• How do you know what is right and wrong?
• How do you know if there is a God or not?
• How do you know something (or someone) is
  beautiful?
• How is science different than these ways of
  knowing?

41
How is the science way unique?

• All observers must get the same result.
• Result of what?
• Experiment
• We agree the nature has the final word on what
  the correct answer is.
• For those of us who believe in God, and that God
  runs nature, good science is a way of listening
  to God.

42
What Is Science?

• A collection of facts?
• NO
• The ideas of a certain group of people?
• NO
• A certain way of doing things?
• YES
• What is this method? (A test question!)

43
Good Science

• Asking the right question
• Making the correct assumptions
• Starting at the correct point
• Accepting the answer Nature (God) gives us
• Experiment has the final word in saying whether
  or not an idea is correct.

44
The Limits of Science

• Mens imperfect ideas about Gods Creation
• We dont know much about anything
• Our knowledge about everything is incomplete
• Science tomorrow will be different than Science
  today
• The questions may be the same but the answers
  will change.

45
According to the most recent scientific theories,
we cannot see most of the matter that makes up
the universe. Data from K C Star, January 11,
2004
46
The expansion of our knowledge

• In ancient times, a different set of laws was
  thought to apply to the Earth and to the
  heavens.
• With the idea of gravity, Newton showed that the
  same laws apply in space between the planets as
  do on Earth.
• As we look at the development of scientific
  knowledge, we see that we have gradually gone
  from just what we can see, to a round Earth, to
  the solar system, to many solar systems.

47
What is gravity?

• A fundamental force
• There are only four different types of forces!
• gravity
• electricity and magnetism
• weak nuclear force
• strong nuclear force 
• (Do we need to add Dark Energy (negative
  gravity?)

48
Gravity

• Explains the orbits of the planets (comets, etc)
• Explains why things fall
• Explains why we dont float in the air why we
  press against the ground (chair)
• Explains why the Earth is round
• Explains why the Earths atmosphere stays and
  doesn't float away into space
• Lead to the discovery of new planets (Neptune and
  Pluto)
• Explained the tides

49
Tides

• High tide is when the moon is overhead
• Two cycles
• Day - two high tides and two low tides every day
• Month - the difference between high and low tide
  increases, then decreases during each month.
• Spring tides
• Moon and sun work together
• Largest difference between high and low tides
• Neap tides
• Sun and moon oppose each other
• Smallest difference between high and low tides

50
Tide animation from NASA.
51
Definition

• Velocity is the distance traveled in a certain
  time divided by the time it takes to travel that
  distance
• Velocity Distance/time
• vd/t
• normal units of velocity are meters/second
• m/s

52
Definition

• Acceleration is the change in the velocity
  divided by the time it takes the velocity to
  change
• Acceleration (final velocity-initial
  velocity)/time
• a (vf - vi)/t
• normal units of acceleration are meters/second
  per second (m/s2)

53
Force

• When a force acts on a mass it causes the mass to
  accelerate.
• Fma
• Forcemass x acceleration
• Units of force are newtons (N)
• 10 newtons 10 N

54
Gravity

• The acceleration of gravity is g 9.8 m/s2
• The force of gravity on a 20 gram object is
• Fmg .02 kg x 9.8 m/s2 0.196 N

55
Pulleys
There is 0.1 kg more on one side of the pulley
than on the other so the accelerating force will
be F mg 0.1 kg x 9.8 m/s2 0.98 N
2.0 kg
2.1 kg
56
Review for Test

• 5 men who developed our ideas about the solar
  system
• The way science works
• Conversion of units
• Tides
• low, high ,spring, neap,

57
More on lab

• Come with the front page filled out
• Bring your calculator
• Come on the day assigned if at all possible
• But be certain to come
• Missing more than 3 labs will result in your
  failing the class, regardless of grade in the
  rest of the class.

58
Quick Review of Metric Conversion (2.54 cm/in)

• Change 2.78 m to ft and inches.
• Begin by changing 2.78 m to 278 cm.
• Then change the cm to inches
• We now need to change the inches to feet and
  inches.
• 9 ft 5ft x 12 in/ft 108 in
• 109 in 9 ft 1 inch

59
Change 50kg to pounds (2.21 lbs/kg)

• Should you multiply or divide by 2.21 lbs/kg?
• 50 lbs 22.6 kg