Chapter 1
Science Skills
1.1 What is Science?
 Science is a system of knowledge and the methods you use to
find that knowledge
 The goal of science is to expand knowledge
 Science often begins with curiosity and often ends with
discovery
 Technology is the use of knowledge to solve practical problems
 The goal of technology is to apply knowledge
 Science and technology are interdependent;
 Advances in one lead to advances in the other
3 branches of science:
1.2 Using a Scientific Approach
 The scientific method = an organized plan for gathering,
organizing, and communicating information
Making Observations
Scientific investigations often begin with observations.
An observation is information that you obtain through your
senses.
Forming a Hypothesis
A hypothesis is a proposed answer to a question.
Remember: a hypothesis must be able to be tested!
Testing a Hypothesis
A variable = any factor that can change in an
experiment
• The manipulated or independent variable
causes a change.
• The responding or dependent variable
changes in response to the manipulated
variable.
A controlled experiment is an experiment in
which only one variable, the manipulated
variable, is changed at a time
Drawing Conclusions
A conclusion describes how facts apply to a
hypothesis.
Developing a Theory
A scientific theory is a well-tested explanation
for a set of observations or experimental results.
A model can be made to better understand
a hypothesis or theory. They are especially
useful for visualizing objects too large or
small to be seen easily.
After repeated observations or
experiments, scientists may arrive at
a scientific law.
A scientific law is a statement that
summarizes a pattern found in
nature.
• For example, Newton’s law of
gravity is a scientific law that has
been verified over and over.
1.4 Presenting Scientific Data
Scientific data should be
organized and clearly
communicated.
Scientists can organize their data by using
data tables and graphs.
The simplest way to organize data is to present them
in a table.
This table relates two variables—a manipulated or
independent variable (location) and a responding or
dependent variable (average annual precipitation).
Which city has the largest average
annual precipitation?
How might the precipitation in
Buffalo differ from the precipitation
in Tallahassee?
Line Graphs
A line graph is useful for showing changes that
occur in related variables.
• In a line graph, the manipulated variable is
generally plotted on the horizontal axis, or xaxis.
• The responding variable is plotted on the
vertical axis, or y-axis, of the graph.
Sometimes the data points in a graph yield a
straight line.
• The steepness, or slope, of this line is the ratio
of a vertical change to the corresponding
horizontal change.
Plotting the mass of water against the
volume of water yields a straight line.
What would be the mass
of 6 cm3 of water?
What is the dependent
variable in this situation?
How can you tell?
This graph shows how the flow rate of a
water faucet affects the time required to
fill a 1-gallon pot.
What is the relationship
between flow rate and
time according to this
graph?
How long does it take to
fill the pot if the flow rate
is 2 gallons per minute?
Bar Graphs
A bar graph is often used to compare a set of
measurements, amounts, or changes.
Circle Graphs
If you think of a pie cut into pieces, you have a
mental model of a circle graph. A circle graph
shows how a part or share of something relates
to the whole.
If you added all the
percentages shown what
would the total be?
Explain.
Communicating Data
Scientists can communicate results by
- writing in scientific journals
- speaking at conferences.
Scientists also exchange information through
conversations, e-mails, and Web sites.
Young scientists often present their research
at science fairs.
1.3 measurement
 Scientific notation is a way of expressing a value as a
product of a number between 1 and 10 and a power of 10
 Ex: 300,000,000 = 3.0 X 108
200 = 2.0 X 102
0.04 = 4.0 X 10-2
0.00086 = 8.6 X 10-4
Scientific notation makes very large or very small numbers
easier to work with
 100 = 1
 101 = 10
 102 = 100
 103 = 1,000
 104 = 10,000
 105 = 100,000
 106 = 1,000,000
 100 = 1
 10-1 = 0.1
 10-2 = 0.01
 10-3 = 0.001
 10-4 = 0.0001
 10-5 = 0.00001
 10-6 = 0.000001
 Measurements require a number and a unit
 Scientists use a set of measuring units called SI =
International System of Units
 The SI system is a revised version of the metric system
 SI is built upon 7 metric units
 Ex: length:
mass:
time:
temp.:
m
kg
s
K
(meter)
(kilogram)
(second)
(Kelvin)
Metric prefixes allow for more convenient
ways to express SI units
Ex:
Giga- (G) = 109 = 1,000,000,000
Mega- (M) = 106 = 1,000,000
Kilo- (k) = 103 = 1,000
More prefixes:
deci- (d) = 10-1 = 0.1
Centi- (cm) = 10-2 = 0.01
Milli- (m) = 10-3 = 0.001
Micro (m) = 10-6 = 0.000001
Nano (n) = 10-9 = 0.000000001
 Limits of measurement:
 Precision indicates how exact a measurement is
 Ex: analog clock measures 15 min
digital clock measures 14 min and 38
seconds
Significant figures are all the digits that are
known in an experiment plus the last digit that is
estimated
The precision of a calculated answer is
limited by the least precise measurement
used in the calculation
Ex: a car travels 68.25 miles in 1.15
hours
the average speed was 68.25 / 1.15 =
59.347826087 MPH
the answer should only have 3 significant
figures 59.3 MPH
Accuracy is the closeness of a
measurement to the actual value of what is
being measured
Ex: a clock that is running late is NOT
accurate
Learning Targets for Chap. 1
1.
2.
3.
4.
5.
6.
7.
8.
Identify and describe the 3 main branches of science
Contrast science and technology.
Describe the steps in the scientific method.
Distinguish between a hypothesis, theory and a law
Describe the importance of using models.
Convert between standard and scientific notation.
Explain the importance of the SI system.
Use the conversion chart to convert between units in the SI
system.
9. Explain the concepts of accuracy and precision
10. Describe when each of the different types of graphs should
be used.
11. Be able to construct a quality graph and analyze the data.