Chapter 1:
The Nature of Science
• Section 1: The Methods of Science
• Section 2: Standards of Measurement
• Section 3: Communicating with Graphs
• Section 4: Science and Technology
Section 1: The Methods of Science
• What is science?
Science is a process that uses observation and
investigation to gain knowledge about events in nature
Science explains nature – science helps you understand
the natural world
Scientists learn about the natural world by performing
investigations
Investigations can be field studies or lab experiments
Section 1: The Methods of Science
The Scientific Method
• An organized problem
solving procedure
• Must have a specific
question or problem
• Depending on the nature of
the investigation, not all
steps need to be used
• Communicating the results
of the investigation is a
critical part of science. It
allows others to test and
confirm your results.
• Vocabulary: hypothesis,
variable, dependent
variable, independent
variable, constant, control
Section 1: The Methods of Science
Scientific Theories and Laws
Science and Technology
• Scientific theory – an
• Technology – the application of
explanation of things or events
based on knowledge gained
from observations and
investigations
Examples: Einstein’s Theory of
Relativity, Darwin’s Theory of
Evolution
• Scientific law – a statement
about what happens in nature
and that seems true all the
time.
Example: The Law of Universal
Gravitation
A scientific law never explains
why or how the law is true
science to help people
• Generally, scientific knowledge
comes before the application
of that knowledge
Example: Experiments that
showed light behaves as a
particle (photon) occurred in the
early 1900’s, today applications
of this knowledge include CD
players and laser scanners
• Think about these questions:
Do science and technology
always produce positive
results?
Is a new technology always
embraced by end users (people
like you)?
Section 2: Standards of Measurement
The Metric System
• Known as the
International System
of Units or SI
• SI base units:
distance = meter
mass = gram
volume = liter (fluid),
= cm3 (solid)
time = second
temperature = Celsius
• Base units are used
with prefixes to
describe large or small
quantities
Prefixes indicate
multiples of ten
Section 2: Standards of Measurement
Converting Between Units
• A powerful problem solving tool called “Dimensional Analysis”
guides a student to the correct solution to a problem
Example 1: 350-cm = ?-m
Solution:
1. We know :
100𝑐𝑚
1𝑚
or
, these are the conversion factors
𝑚
100𝑐𝑚
for possible use in solving this problem.
2. We set the solution up as a multiplication problem using the
conversion factor that will leave us with the unit of “meter”
1𝑚
350𝑐𝑚 𝑥 1𝑚 350𝑚
350𝑐𝑚
=
=
= 𝟑. 𝟓𝟎𝒎
100𝑐𝑚
100𝑐𝑚
100
3. Notice that the “cm” units cancel, and the unit remaining in the
problem is meters, “m”. That is the dimensional analysis for this
problem.
Hint: Always set up the problem so that the unit you are solving
for is in the numerator of the conversion factor and the unit you
want to get rid of is in the denominator of the factor.
Section 2: Standards of Measurement
Converting Between Units (cont.)
Example 2: 0.25kg = ? cg
Solution
1. There is no direct relationship between kilograms and
centigrams, so the solution requires two steps – converting
kilograms to grams and then converting grams to centigrams
2. Conversion factors for these units:
1000𝑔 1𝑘𝑔
1𝑔
,
,
,
1𝑘𝑔 1000𝑔 100𝑐𝑔
and
100𝑐𝑔
1𝑔
3. Step 1: convert kilograms to grams
1000𝑔
0.25𝑘𝑔 𝑥1000𝑔
0.25𝑘𝑔
=
= 250𝑔
1𝑘𝑔
1𝑘𝑔
4. Step 2: convert grams to centigrams
100𝑐𝑔
250𝑔 𝑥 100𝑐𝑔
250𝑔
=
= 𝟐𝟓, 𝟎𝟎𝟎𝒄𝒈
1𝑔
1𝑔
Notice that using the correct conversion factor and doing the
dimensional analysis makes solving this difficult problem fairly
easy.
Section 2: Standards of Measurement
Density
Density is the mass per unit volume of a material
• Mass is the amount of matter in an object
•
Volume is the amount of space an object occupies
• Volume of a liquid is measured in liters
• Volume of a solid is measured in meters3 (or some
multiple)
•
Different materials can have the same mass but different
densities
•
The density of a substance can help identify the substance
•
The equation for density:
𝒎
𝝆=
𝑽
•
Where: ρ =density
m = mass
V = volume
Typically, the unit for density will be g/cm3 or g/L
Section 2: Standards of Measurement
Example:
A block of wood 5 cm x 7.5 cm x 2.5 cm has a mass of 150 g. What is
the density of the wood block?
Solution:
V=lxwxh
l=5.0 cm
= 5.0cm x 7.5cm x 2.5 cm
w =7.5 cm
h =2.5 cm V = 93.75 cm3
m = 150g
ρ =?
𝜌=
𝑚
150𝑔
𝒈
=
=
𝟏.
𝟔𝟎
𝑉 93.75𝑐𝑚3
𝒄𝒎𝟑
Your solution must include the following:
• A list of the known variables and what you are solving for
• The equation(s) used to solve the problem
• All work and dimensional analysis.
Section 3: Communicating with Graphs
Many experiments and investigations result in the
accumulation of a large quantity of numerical data. This
data must be organized before it can be used to make any
conclusions.
Graphs are used to organize numerical data.
There are three basic types of graphs:
• Line graphs
• Bar graphs
• Pie graphs
Section 3: Communicating with Graphs
Line graphs – Show the relationship where the dependent variable
changes as the independent variable changes
• Dependent variable – factor that changes as the independent
variable changes
• Independent variable – factor that, as it changes, affects the
measure of another variable
• To create a line graph:
1. Determine which of the variables is the dependent
variable and which in the independent variable
2. Draw and label the x- and y-axis, placing the
independent variable on the x-axis and the dependent
variable on the y-axis
3. Plot the coordinates
4. Connect the points
Example: A lab assignment is to measure the change in water
temperature over time as heat is applied to the water. The
following data was collected. Graph the data.
time
0s
30s
60s
90s
120s
150s
180s
210s
240s
temp
20oC
22
31
40
48
56
70
82
100
Section 3: Communicating with Graphs
Bar graph – useful for comparing information by counting
Example: The results of the first test are summarized in the table
below. Graph the results
grade
A
AB+
B
BC+
C
CD+
D
DF
# students
1
2
2
4
3
4
3
3
2
1
1
1
Section 3: Communicating with Graphs
Pie graphs – used for comparing parts of a fixed quantity
•
To create a pie graph:
• calculate % of total of each part
• 360o in a circle
• apply % to 360o
• measure, draw, and label graph
Example: Comparing the class sizes at Spearfish High School
(total enrollment is 600 students)
# of
Students
Freshman
100
Sophomores
150
Juniors
180
Seniors
170
Grade
Section 4: Science and Technology
Technology – the application of scientific knowledge to benefit
people. Can be:
• Any human made object
• Methods or techniques for making any object or tool
• Knowledge or skills needed to operate a human-made object
• A system of people and objects used to do a particular task
Society and Technology
• Society affects how new technologies develop:
• If people support a new technology that technology will
continue to be developed
• Example: Alternative fuel automobiles, why is this technology
being developed now instead of 40 years ago?
Economics and technology
• Development of new technologies is funded by different sources
including state and federal governments, private foundations,
and private industries
Ethics and technology
• Development of new technologies can pose ethical problems
about their use
• Example: The development of the atom bomb. Good thing:
dropping the bombs shorten the war and prevented thousands
of U.S. casualties. Bad thing: Resulted in the proliferation of
nuclear bombs.
What are some moral or ethical issues that must be considered as
new technologies are developed?