Science

1
Science

• What is SCIENCE?
• How is SCIENCE done?
• How do we KNOW what we know?
• The Scientific Method Orientation Page
• http//pls.atu.edu/physci/physics/people/psjr/cour
  ses/SciMethodAppendix.html

2
The Scientific Method

• Demonstration Combustion of Ethyl Alcohol

3
The Scientific Method
4
The Scientific Method

• Science is a human activity, done by humans for
  humans
• A scientist predicts what can or can not happen,
  and NOT what will or will not happen.
• A fact is not absolute, but a close agreement by
  many different observers, over many trials on
  verifiable and testable hypotheses. Sometimes
  only what is the most probable is obtained.
• Embrace ideas that can be tested.

5
Science Questions

• Science is only interested in questions that have
  an experimentally verifiable end.
• There must be a Test for wrongness or rightness.
• If there is no Experiment (Test), there is no
  science.
• Not interested in speculations.
• Beware Pseudo-Science!
• Extraordinary Claims Demand Extraordinary
  Evidence!

6
Astronomy Versus Astrology

• Astrology is an ancient superstition that hold
  that a persons personality and actions are
  influenced by the positions of the sun, moon,
  planets, and stars at the moment of birth. In
  addition, astrologers claim that the daily
  changes in the location of heavenly bodies can
  influence events in our everyday lives. All of
  this is summarized in a horoscope, which includes
  a diagram of the zodiac, showing the precise
  positions of the heavenly bodies in their orbits.
  
• Is there any physical reason we should expect
  astrology to work, except that it might appeal to
  our needs? There seems to be no way for the
  various heavenly bodies to interact on the body
  of a baby at birth, except via gravity. The
  force of gravity exerted on the baby by the
  doctor is many times larger than that of the sun
  and planets. Thus, it would seem more important
  where the doctors and nurses stand in the room
  rather than the orientation of the sun, moon,
  mars and the earth.

7
Astronomy Versus Astrology

• Is there any evidence that astrology does work?
  Astrology has been tested many times over, and no
  legitimate test has proven any astrological
  influence on our lives. Extensive tests have
  searched in vain for relationships between birth
  date and profession, blood type, handedness,
  divorce rate, etc.
• Yes it is based on science Celestial Mechanics,
  NO it doesnt influence our lives. Use it like
  you would flipping a coin or for entertainment
  along with the Sunday Funnies or fortune cookies.

8
A Scientific Claim

• Which of the following is a scientific claim?

9
A Scientific Claim

• 1 Is the only statement which can be verified.
• It can be verified to be wrong.

10
Conceptual Problem

• A Physical Model is needed to describe the things
  needed to calculate how long it takes water to go
  from Dardanelle to Petit Jean.
• Step 1 What factors might be involved?

11
Conceptual Problem

• A Physical Model is needed to describe the things
  needed to calculate how long it takes water to go
  from Dardanelle to Petit Jean.
• Step 1 What factors might be involved?
• Gravity
• Topography
• Viscosity
• Rain Fall History and Locations
• Wind
• Dam Outflow Rate

12
Conceptual Problem

• A Physical Model is needed to describe the things
  needed to calculate how long it takes water to go
  from Dardanelle to Petit Jean.
• Step 1 What factors might be involved?
• Gravity
• Topography
• Viscosity
• Rain Fall History and Locations
• Wind
• Dam Outflow Rate
• Create a model from these to come up with an
  amount of time.

13
Standard Units of Measurement

• Fundamental Units
• MKS CGS
• Length L meter m centimeter cm
• Mass M kilogram kg gram gm
• Time T seconds s second s

14
Standard Units of Measurement

• Derived Units
• Area L2 square meters m2 square centimeters cm2
• Volume L3 cubic meters m3 cubic centimeters cm3
• Velocity L/T meters/second m/s centimeters/second
  cm/s
• Density M/L3 kilogram/cubic meter kg/m3
  g/cm3
• Acceleration L/T2 meter/second2 m/s2
  cm/s2
• FORCE ML/T2 kilogram meter/ second2 kg
  m/s2 g cm/s2

15
Units and Conversions

• Milli 1/1000 X 10-3
• Centi 1/100 X 10-2
• Kilo 1000 X 103
• Mega 1 million X 106
• Giga 1 billion X 109
• Reference Pages
• http//physics.nist.gov/PhysRefData/contents.html
  
• http//chemistry.berkeley.edu/links/weights/equiva
  lences.html

16
SCIENTIFIC NOTATION RULES

• I. Convert the number to a number between 0.0-9.9
• II. Multiply by the power of ten that will yield
  the original
• number. Positive exponents move the decimal
  point to the
• right, negative to the left.
• Examples
• 0.00123 1.23 x 10-3
• 3,401,000 3.401 x 106

17
Scientific Notation

• Scientific notation is designed to clear up how
  accurate a
• number is as well as make it easier to represent
  very large and
• very small numbers.
• Example 1500
• The zeros are misleading. Is it 1500 ? 1
• 1500 ? 100
• A measurement without its associated error value
  is worthless.
• With scientific notation it can be made easier to
  see what is
• reliably known.

18
Scientific Notation

• With scientific notation it can be made easier to
  see what is
• reliably known.
• 1500 ? 1 would be expressed as 1.500 x
  103
• 
  4 significant digits
• 1500 ? 100 would be expressed as 1.5 x 103
• 
  2 significant digits

19
Significant Digits

• The number of significant digits quoted in an
  answer must be equal to the number of significant
  digits in the least accurate input item.

20
Significant Digits

• The number of significant digits quoted in an
  answer must be equal to the number of significant
  digits in the least accurate input item.
• Example A rectangular area is measured with a
  ruler
• having 0.1 cm accuracy. What is the area of the
  rectangle?
• Width 4.5 cm
• Length 16.3 cm
• A calculator yields an answer for the
• Area (16.3)(4.5) 73.35 cm2
• But the least significant input was 4.5 with two
  significant
• figures, so the answer should be 73 cm2???

21
Errors and Accuracy

• Why do we have to quote an answer that appears to
  be less
• accurate than our ruler accuracy of ? 0.1 cm?
• The real measurements were
• Width 4.5 ? 0.1 cm

22
Average(G) and Standard Deviation(s)

• A Particular Individuals Score (g)

23
Average(G) and Standard Deviation(s)

• A Particular Individuals Score (g)

24
Average(G)

• PEAK Average
• The Average represents the most probable value
  encountered in many many measurements.

25
Standard Deviation(s)

• Width Standard Deviation
• The standard Deviation (sigma) represents the
  spread of values about the average. A large
  spread implies less accuracy or less confidence
  in the mean value. Measurements are often quoted
  as the mean plus or minus 1 standard deviation.
  Mathematically this is equivalent to saying that
  a particular measurement is 67 likely to fall
  within the range (mean - 1 sigma) to (mean 1
  sigma) OR 98 likely to fall within the range
  (mean - 2 sigma) to (mean 2 sigma) .

26
Errors and Accuracy

• Why do we have to quote an answer that appears to
  be less
• accurate than our ruler accuracy of ? 0.1 cm?
• The real measurements were (mean of 4.5, standard
  deviation of 0.1)
• Width 4.5 ? 0.1 cm

27
Errors and Accuracy

• Why do we have to quote an answer that appears to
  be less
• accurate than our ruler accuracy of ? 0.1 cm?
• The real measurements were (mean of 4.5, standard
  deviation of 0.1)
• Width 4.5 ? 0.1 cm which means any value
  between 4.4-4.6

28
Errors and Accuracy

• Why do we have to quote an answer that appears to
  be less
• accurate than our ruler accuracy of ? 0.1 cm?
• The real measurements were (mean of 4.5, standard
  deviation of 0.1)
• Width 4.5 ? 0.1 cm which means any value
  between 4.4-4.6
• Length 16.3 ? 0.1 cm

29
Errors and Accuracy

• Why do we have to quote an answer that appears to
  be less
• accurate than our ruler accuracy of ? 0.1 cm?
• The real measurements were (mean of 4.5, standard
  deviation of 0.1)
• Width 4.5 ? 0.1 cm which means any value
  between 4.4-4.6
• Length 16.3 ? 0.1 cm which means any
  value between 16.2-16.4

30
Errors and Accuracy

• Why do we have to quote an answer that appears to
  be less
• accurate than our ruler accuracy of ? 0.1 cm?
• The real measurements were (mean of 4.5, standard
  deviation of 0.1)
• Width 4.5 ? 0.1 cm which means any value
  between 4.4-4.6
• Length 16.3 ? 0.1 cm which means any
  value between 16.2-16.4
• The area could have been (16.2)(4.4) 71.28 cm2
• (16.4)(4.4) 72.16 cm2
• (16.2)(4.6) 74.52 cm2
• (16.4)(4.6) 75.44 cm2

31
Unit Conversions

• Example How many kilometers is 50,000 inches?

32
Unit Conversions

• Example How many kilometers is 50,000 inches?

33
Unit Conversions

• Example How many kilometers is 50,000 inches?

34
Unit Conversions

• Example How many kilometers is 50,000 inches?

35
Unit Conversions

• Example How many kilometers is 50,000 inches?
• 1.27 km

36
Unit Conversions

• Example How many kilometers is 50,000 inches?

37
Unit Conversions

• Example How many kilometers is 50,000 inches?

38
Unit Conversions

• Example How many kilometers is 50,000 inches?

39
Unit Conversions

• Example How many kilometers is 50,000 inches?

40
Unit Conversions

• Example How many kilometers is 50,000 inches?
• 1.27 km

41
Unit Conversions

• If I run 10 m/s in a school zone posted 20
  miles/hour,
• am I speeding?

42
Unit Conversions

• If I run 10 m/s in a school zone posted 20
  miles/hour,
• am I speeding?

43
Unit Conversions

• If I run 10 m/s in a school zone posted 20
  miles/hour,
• am I speeding?

44
Unit Conversions

• If I run 10 m/s in a school zone posted 20
  miles/hour,
• am I speeding?

45
Unit Conversions

• If I run 10 m/s in a school zone posted 20
  miles/hour,
• am I speeding?

46
Unit Conversions

• If I run 10 m/s in a school zone posted 20
  miles/hour,
• am I speeding?
• 22.3 miles/hour YES

47
Unit Conversions

• Can I jump over 1 million dollars if it takes
  1,000
• dollar bills to stack up to 1 inch?

48
Unit Conversions

• Can I jump over 1 million dollars if it takes
  1,000
• dollar bills to stack up to 1 inch?

49
Unit Conversions

• Can I jump over 1 million dollars if it takes
  1,000
• dollar bills to stack up to 1 inch?
• 83 feet I think NOT!

50
PHYS 1114 Assignment

• Visit the Class Web Space (PHYS 1114)
• http//pls.atu.edu/physci/physics/people/psjr/co
  urses/
• Read Your Textbook Inquiry Into Physics
• Appendix B and Chapter 1
• Homework Chapter 1
• Questions 3, 6, 8, 12-14, 18, 19, 21, 22
• Problems 2, 4, 7, 8, 10, 11, 13
• Challenges 1, 5, 7