Chapter 1: Nature of Science
• What is a scientist and what
does he do?
– Scientists investigate
– Scientists plan experiments
– Scientists observe
– Scientists test results
– SCIENTISTS ASK GOOD
QUESTIONS!
Pure Science vs. Technology
• Pure Science is scientific
knowledge gained by
observation and experiment.
• Technology is the application of
pure science to meet human
needs.
Scientific Theory
• A scientific theory is a tested,
explanation of a natural event.
[Theories have not been proven]
– A theory must explain observations
simply and clearly.
– Experiments that illustrate the theory
must be repeatable.
– You must be able to predict from the
theory.
Scientific Law
• A scientific law is a description of a
natural event. [Laws have been proven]
– Newton’s law of gravity
– Newton’s laws of motion
– Hooke’s law
– Kepler’s laws of planetary motion
– Etc.
Section 1.1 Review:
• Explain how science and technology
depend on each other.
• How does a scientific law differ from
a theory?
• Pick a common phenomenon and
develop a theory about it, what kind
of experiment could you do to test
the theory?
Section 1.2
The Way Science Works
• Critical thinking is a basic skill of a
scientist. It is applying logic and reason to
observations and conclusions.
• The scientific method is a series of logical
steps to follow in order to solve a problem
or answer a question. (pg. 13 fig 1-12)
Scientific Method [5 steps]
• Make an observation
• Form an hypothesis
• Make predictions
• Test the hypothesis
• Draw a conclusion
Systeme International d' Unites – SI
Measurement System
1.
2.
3.
4.
5.
6.
7.
Base Units of SI System (total of 7)
Length – Meter, m
Mass – Kilogram, kg
Time – Second, s
Temperature – Kelvin, K
Electric current – ampere, A
Amount of substance – mole, mol
Luminous intensity – candela, cd
Systeme International d' Unites – SI
Measurement System
•
•
•
•
•
•
Derived Units of SI System (hundreds)
Force – Newton, N
Area – Square meters, m2
Volume (liquid)– Liter, L.
Velocity – meters/second, m/s
Acceleration - meters/second/second, m/s2
Pressure- N/m2
Examples of SI Measurement
System units
• Length – meter, m
• Force or weight – Newton, N
• Mass – kilogram, kg
• Area – m2
• Volume – m3
• Density – g/cm3
• Time – second, s
• Temperature – degrees Celsius, oC
Examples of English Measurement
System units
• Length – feet, ft
• Force or weight – pounds, lbs
• Area – square feet, ft2
• Volume – cubic feet, ft3
• Density – pound per cubic feet, lb/ft3
• Time – seconds, s
• Temperature – degrees Fahrenheit, oF
• Etc.
Scientific Notation
In many branches of science, some numbers are
very small, while others are quite large. To
conveniently express these numbers, scientists
use a type of shorthand called scientific notation
to express the number as a multiplier and a power
of 10.
0.00000325 = 3.25 x 10-6
422,000,000,000,000 = 4.22 x 1014
Significant Figures
• For numbers with no decimal point, start
from the “atlantic” right hand side and
count all digits beginning with the first nonzero digit.
– Ex: 45000 has two sig. figs.
• For numbers with a decimal point, start
from the “pacific” left hand side and count
all digits beginning with the first non-zero
digit.
Scientific Notation
• Scientific Notation: a value written as a
simple number multiplied by a power
of 10.
– Ex: 10000 = 104
0.001 = 10-3
– Why is one positive and the other
negative?
– Very large #’s are positive and very small
#’s are negative.
Metric Prefixes
Prefix Symbol
Meaning
kilok
1000
hecto-h
100
dekada
10
Base Unit----------------------------------decid
0.1
centic
0.01
millim
0.001
microm
0.000001
nanon
0.000000001
Meaningful Metric Prefixes
Prefix
teragigamegakilo-
Symbol
T
G
M
k
Meaning
1000000000000 or 1012
1000000000 or 109
1000000 or 106
1000 or 103
millimicronanopico-
m
m
n
p
0.001 or 10-3
0.000001 or 10-6
0.000000001 or 10-9
0.000000000001 or 10-12
Converting temperature
• Conversion of Fahrenheit to Celsius
oC
= 5/9 [oF - 32]
• Conversion of Celsius to Fahrenheit
oF
= [9/5 x oC] + 32
Section 1.2 cont..
• A conversion factor is used to convert
between units.
• Ex: How many centimeters are in 1.85
inches?
1.85 in x [2.54 cm/1 in]
4.70 cm
Ex: How many
Section 1.2 cont…
• How to set up a conversion factor:
• #1: Always write what you are given
FIRST!
• #2: Put what you are looking for on top of
the conversion line.
• #3: Put what you are trying to cancel out on
the bottom of the conversion line.
Conversion Factor Process
• Ex: Write 550 millimeters as meters
• #1: given: 550 millimeters
• #2: looking for meters
• #3: want to cancel millimeters
• 550 mm x 1 m/1000 mm
• Calculate: 550 x 1 / 1000 = 0.55 m
Conversion Practice
• Convert the following:
– 1.6 kilograms to grams
– 2500 milligrams to kilograms
– 0.4 millimeters to
micrometers
– 2800 millimoles to moles
– 6.1 amperes to milliamperes
1600 g
.0025 Kg
400 mm
2.8 mol
6100 mA
Section 1.2 Making Measurements
• There are many observations that
rely on quantative measurements.
The most basic scientific
measurements generally answer how
big, how much, or how much time.
• We use length, mass, time, and
volume as quantative measurements
in labs.
• Remember:
– Length = meters
– Mass = grams
– Volume = liters or cubic centimeters cm3
Organizing Data
• There are several ways to organize lab data.
– Data Chart: Good way of keeping track
of something over time or making several
readings on a topic. Usually done as raw
data.
– Graphs: A good way to organize your
raw data and show trends, inferences, or
results.
Graphs
• There are several types of graphs.
– Line graph: shows change over time
– Bar graph: good for comparing data for
several individual items or events
– Pie chart: ideal for displaying data that
are parts of a whole
Line Graph
• Independent variable: goes
on the x axis. That is the
bottom of the graph. Here
the time in days is the
independent variable. This
variable is determined by
the experimenter.
• Dependent variable: what is
changing in the experiment.
This is not determined by
the experimenter.
Bar Graph
What you’re comparing goes on the x axis
Pie Chart