1. Chapter 1: The Science of Physics
Mr. Chumbley

2. Section 1: What is Physics?

3. The Topics of Physics
The origin of the word physics comes from the ancient Greek word phusika meaning “natural things”
The types of fields of physics vary from the very small to the very large
While some physics principles often seem removed from daily life, those same laws those same laws describe everyday events as well

4. Areas of Physics Name Subjects Examples Mechanics
motion, interactions between objects
falling objects, friction, weight, moving objects
Thermodynamics
heat and temperature
melting and freezing processes, engines, refrigerators
Wave Mechanics
specific types of repetitive motion
springs, pendulums, sound
Optics
light
mirrors, lenses, color
Electromagnetism
electricity, magnetism, light
electrical charge, circuitry, permanent magnets, electromagnets
Relativity
Particles moving at speed, generally very high speed
particle accelerators and collisions, nuclear energy
Quantum Mechanics
Behavior of subatomic particles
the atom and its parts

5. What is Physics?
How can physics be defined if it so many different things?
Physics can be defined as:
The study of matter, energy, and the interactions between them
This definition is basic yet very broad

6. The Scientific Method All scientific studies begin with a question
There is no single procedure all scientists follow
The scientific method is a set of steps that is common to most high quality scientific investigations

7. Using Models to Describe Phenomena
The physical world is very complex
In order to simplify the world, physicists construct models to isolate and explain the most fundamental aspects of a phenomenon
A model is a pattern, plan or description designed to show the structure or workings of an object, system, or concept
Models come in a variety of forms

8. Using Models to Describe Phenomena
In order to simplify the model, only the relevant components are considered part of the system
A system is a set of particles or interacting components considered to be a distinct physical entity for the purpose of study
Components not considered part of the system can generally be considered to have little to no impact on the model

9. Models and Experimentation
Models are extremely beneficial in helping to design experiments
Once a phenomenon has been identified, a hypothesis can be formed
A hypothesis is an explanation that is based on prior scientific research or observations and that can be tested
By creating a model of the phenomenon, the necessary factors for designing an experiment can be identified

10. Models and Experimentation
A model helps to ensure that controlled experiments are set up
A controlled experiment is an experiment that tests only one factor at a time by using a comparison of a control group with an experimental group

11. Models and Predictions
Once a model has been tested and supported repeatedly, that model can then be used to make predictions of future events
The best scientific models are used to predict outcomes in different scenarios that are different than the initial system

12. Homework Read Chapter 1, Section 1: What is Physics?
Answer #1-5 of the Formative Assessment Questions on p. 9

13. Section 2: Measurements in Experiments

14. What Can a Measurement Tell You?
Often times we look at measurements as simple values, yet these values are different than simple numbers
A measurement tells dimension, the kind of physical quantity
A measurement tell the magnitude of the physical quantity
A measurement tells the unit by which the physical quantity is expressed

15. Standard System of Measurement
In 1960, an international committee agreed upon the Système International d’Unités (SI) for scientific measurements
The most common basic units of measure are:
Unit
Symbol
Dimension
Original Standard
Current Standard
meter m
length
One ten-millionth distance from equator to pole
Distance traveled by light in a vacuum in × 10-9 s
kilogram kg
mass
Mass of cubic meters of water
Mass of a specific platinum-iridium alloy cylinder
second s
time
average solar days
9,192,631,770 times the period of a radio wave emitted from a cesium-133 atom

16. Standard System of Measurement
Not every dimension can be described using just one of these units
Derived units are formed when units are combined with multiplication and division
Units help to identify the type of quantity being observed or measured

17. SI Prefixes Smaller than base unit Larger than base unit Prefix Power
Abbreviation
yocto
10-24 y
zepto
10-21 z
atto
10-18 a
femto
10-15 f
pico
1o-12 p
nano
10-9 n
micro
10-6
milli
10-3 m
centi
10-2 c
deci
10-1 d
Prefix
Power
Abbreviation
deka
101 da
hecto
102 h
kilo
103 k
mega
106 M
giga
109 G
tera
1012 T
peta
1015 P
exa
1018 E
zetta
1021 Z
yotta
1024 y

18. Using SI Prefixes
The advantage of using SI and its prefixes is that it can put numbers into understandable values
Converting between one unit to another is simply a matter of moving the decimal

19. SI Conversions
To convert between one unit and another we use a conversion factor
Conversion factors are built from any equivalent relationship
The value of a conversion factor is always equal to 1
Desired unit for conversion is opposite the location of the original unit

20. Conversion factor for mm to m is: 10 −3 m 1 mm
SI Conversions
Example #1:
Convert 37.2 mm to m.
Conversion factor for mm to m is: 10 −3 m 1 mm
37.2 mm × 10 −3 m 1 mm =3.72× 10 −2 m

21. Scientific Notation
Scientific notation is a way of expressing numbers consistently
The format for scientific notation is a value, called the significand, that is expressed as a value with a single digit left of the decimal point multiplied by a power of 10
For example
112=1.12× 10 2

22. Practice! Find a partner nearby
Complete the Practice problems on page 15, #1-5

23. Homework
Chapter 1 Review p
Complete # 5, 8, 10, 11, 12, 13

24. Accuracy and Precision
A description of how close a measurement is to the correct or accepted value of the quantity measured
The degree of exactness of a measurement

25. Uncertainty and Error
Uncertainty is the measure of confidence in a measurement or result
Uncertainty can arise from a variety of sources of error
Method error occurs when measurements are made using inconsistent instruments, techniques, or procedures
Instrument error occurs when the tools used to take measurements have flaws

26. Precision and Instruments
The exactness of a measurement is often times dependant upon the tool used
When taking measurements with a tool, the precision of that tool is the smallest marked measurement
Precision can often times be improved by making an estimation of one additional digit
While an estimated digit carries a level of uncertainty, it still provides greater precision

27. Significant Figures
One way we indicate precision in measurement is through significant figures
Significant figures are those digits in a measurement that are known with certainty plus the first digit that is uncertain

28. Significant Figures and Scientific Notation
When the last digit in a measurement is zero, there can be confusion concerning the value
In this situation, using scientific notation can add additional clarity since scientific notation includes all significant figures

29. Rules for Determining Significant Figures (Figure 2.9 on page 18)
Example
1. Zeroes between other nonzero digits are significant.
50.3 m has three significant figures
s has five significant figures
2. Zeroes in front of nonzero digits are not significant.
0.892 kg has three significant figures
ms has one significant figure
3. Zeroes that are at the end of a number and also to the right of the decimal are significant.
57.00 g has four significant figures
kg has seven significant figures
4. Zeroes at the end of a number but to the left of the decimal are significant if they have been measured or are the first estimated digit; otherwise, they are not significant.
1000 m has one significant figure
1030 s has three significant figures

30. Rules for Calculating with Significant Figures (Figure 2
Rules for Calculating with Significant Figures (Figure 2.10 on page 19)
Type of Calculation
Rule
Example
Addition or Subtraction
Given that addition and subtraction take place in columns, round the final answer to the first column from the left containing an estimated digit
round
Multiplication or Division
The final answer has the same number of significant figures as the measurement having the smallest number of significant figures
123 × round 658

31. Calculators and Calculations
Calculators do not take into account significant figures
While the calculator can give you the value of a calculation, determining the number of significant figures is done manually
When rounding occurs multiple times within a calculation, there can be significant error
Generally, it is better to carry extra non-significant digits in calculations and round the answer to the appropriate number of significant digits at the very end

32. Rules for Rounding in Calculations (Figure 2.11 on page 20)
What to do
When to do it
Example (3 SF)
Round down
Whenever the digit following the last significant figure is 0, 1, 2, 3, or 4
30.24 becomes 30.2
If the last significant figure is an even number and the next digit is a 5, with no other nonzero digits
32.25 becomes 32.2
becomes 32.6
Round up
Whenever the last significant figure is 6, 7, 8, or 9
22.49 becomes 22.5
If the digit following the last significant digit is a 5 followed by a nonzero digit
becomes 54.8
If the last significant figure is an odd number and the next digit is a 5, with no other nonzero digits
54.75 becomes 54.8
becomes 79.4

33. Homework Section 2: Formative Assessment (p 20)
#3 and #4
Chapter 1 Review (p 28)
#16, 20, 22

34. Section 3: The Language of Physics

35. Mathematics and Physics
In physics, the tools of mathematics is used to analyze and summarize observations
This can be in a variety of forms, most commonly tables, graphs, and equations

36. Distance golf ball falls (cm) Distance table-tennis ball falls (cm)
Tables
Data Table: Time and Distance of Dropped-Ball Experiment
Tables are a convenient way to organize data
Having data organized in a table allows for easier use for comparison or calculation
All tables and data should be clearly and appropriately labeled
Time (s)
Distance golf ball falls (cm)
Distance table-tennis ball falls (cm)
0.000
0.00
0.067
2.20
0.133
8.67
0.200
19.60
19.59
0.267
34.93
34.92
0.333
54.34
54.33
0.400
78.40
78.39

37. Graphs
Constructing graphs can help to identify relationships or patterns
The relationships described in graphs can often times be put into equations

38. Equations
In mathematics equations are used to describe relationships between variables
In physics, equations serve as tools to describe the measurable relationships between physical quantities in a situation

39. Equations and Variables
Generally, scientists strive to make equations as simple as possible
To do this scientists use different operators and variables in place of words:
∆𝑦=4.9 (∆𝑡) 2
Quantity
Symbol
Units
Unit Abbreviation
Change in vertical position Δy
meters m
Change in time Δt
seconds s
Mass
kilograms kg
Sum of all forces ΣF
newtons N

40. Dimensional Analysis
Dimensional analysis is a procedure that can be used to determine the validity of equations
Since equations treat measurable dimensions as algebraic quantities, mathematical manipulations can be performed

41. Order of Magnitude
Dimensional analysis can also be used to check answers
Using basic estimation to a power of 10, simple calculations can be made to determine the relative scale of the answer

42. Derived Units with Dimensional Analysis
Similar to converting between base units in SI, conversions of derived units is sometimes necessary
When this happens, each portion of the derived unit needs to be converted