Chapter 1
Science Skills
1.1 What is Science?
Science Skills
1.1 What is Science?
• Science involves asking questions and
then finding ways to answer them.
• Throughout history, humans have had a
strong sense of curiosity.
• Human curiosity led to the use of fire, the
building of tools, and the development of
languages.
1.1 What is Science?
Science Skills
• Science is a system of knowledge and the
methods used to find that knowledge.
• Science begins with curiosity and often
ends with discovery.
1.1 What is Science?
Science Skills
• Curiosity provides questions but is seldom
enough to achieve scientific results.
• Methods such as observing and measuring
provide ways to find answers.
1.1 What is Science?
Science Skills
Science and Technology
• As scientific knowledge is discovered, it
can be applied in ways that improve the
lives of people.
• Technology is the use of knowledge to
solve practical problems.
1.1 What is Science?
Science Skills
• While the goal of science is to expand
knowledge, the goal of technology is to
apply that knowledge.
• Science and technology are
interdependent. Advances in one lead to
advances in the other.
1.1 What is Science?
Science Skills
Branches of Science
• The study of science is divided into social
and natural science.
• Natural science is generally divided into
three branches:
– physical science,
– Earth and space science,
– and life science.
1.1 What is Science?
Science Skills
• The two main areas of physical science
are chemistry and physics.
– Chemistry is the study of the
composition, structure, properties, and
reactions of matter.
– Physics is the study of matter and
energy and the interactions between the
two through forces and motion.
1.1 What is Science?
Science Skills
• The application of physics and chemistry
to the study of Earth is called Earth
science.
• The foundation of Earth science is
geology, the study of the origin, history,
and structure of Earth.
1.1 What is Science?
• The foundation of space science is
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astronomy, the study of the universe
beyond Earth, including the sun, moon,
planets, and stars.
1.1 What is Science?
Science Skills
• The study of living things is called biology.
• Biology is not only the physics and
chemistry of living things, but the study of
the origin and behavior of living things.
• The boundary between each area of
science is not always clear.
1.1 What is Science?
Science Skills
1.1 What is Science?
Science Skills
Science and Your Perspective
• Science is both a process and a body of
knowledge.
• Be aware that the scientific facts of today
might change tomorrow.
1.2 Using a Scientific Approach
Science Skills
1.2 Using a Scientific Approach
1.2 Using a Scientific Approach
Science Skills
Scientific Methods
• In order to answer questions about the
world around them, scientists need to get
information.
• An organized plan for gathering,
organizing, and communication
information is called a scientific method.
1.2 Using a Scientific Approach
Science Skills
• The goal of any scientific method is to
solve a problem or to better understand
an observed event.
• Figure 7 on page 8 outlines an example of
a scientific method.
• Each step in the method shown involves
specific skills.
1.2 Using a Scientific Approach
Science Skills
1.2 Using a Scientific Approach
Science Skills
1.2 Using a Scientific Approach
Science Skills
1.2 Using a Scientific Approach
Science Skills
1.2 Using a Scientific Approach
Science Skills
1.2 Using a Scientific Approach
Science Skills
1.2 Using a Scientific Approach
Science Skills
Making Observations
• Scientific investigations often begin with
observations.
• An observation is information obtained
through the senses.
• Repeated observations are known as facts.
1.2 Using a Scientific Approach
Science Skills
Forming a Hypothesis
• A hypothesis is a proposed answer to a
question.
• For a hypothesis to be useful, it must be
testable.
1.2 Using a Scientific Approach
Science Skills
Testing a Hypothesis
• Scientists perform experiments to test
their hypothesis.
• In an experiment, any factor that can
change is called a variable.
• The manipulated variable causes a change
in the other.
• The responding variable changes in
response to the manipulating variable.
1.2 Using a Scientific Approach
Science Skills
• To examine the relationship between a
manipulated variable and a responding
variable, scientists use a controlled
experiment.
• The controlled experiment is an
experiment in which only one variable, the
manipulated variable, is changed at a
time.
1.2 Using a Scientific Approach
Science Skills
Drawing Conclusions
• What happens if the data do not support
the hypothesis?
• The scientist can revise the hypothesis or
propose a new one, based on the data
from the experiment.
• A new experiment must then be designed
to test the revised or new hypothesis.
1.2 Using a Scientific Approach
Science Skills
Developing a Theory
• Once a hypothesis has been supported in
repeated experiments, scientists can begin
to develop a theory.
• A scientific theory is a well-tested
explanation for a set of observations or
experimental results.
1.2 Using a Scientific Approach
Science Skills
• Theories are not proved. They become
stronger if the facts continue to support
them.
• If an existing theory fails to explain new
facts and discoveries, the theory may be
revised or a new theory may replace it.
1.2 Using a Scientific Approach
Science Skills
Scientific Laws
• 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.
1.2 Using a Scientific Approach
Science Skills
• A scientific law describes an observed
pattern without attempting to explain it.
• The explanation of such a pattern is
provided by a scientific theory.
1.2 Using a Scientific Approach
Science Skills
Scientific Models
• Scientific models make it easier to
understand things that might be too difficult
to observe directly.
• Models may be either mental or physical.
• As long as a model lets you mentally picture
what is supposed to be represented then the
model has done its job.
1.2 Using a Scientific Approach
Science Skills
• Science works by making mistakes.
• The fact that newer models are continually
replacing old models is sign that new
discoveries are continually occurring.
• As the knowledge that makes up science
keeps changing scientists develop a better
and better understanding of the universe.
1.2 Using a Scientific Approach
Science Skills
Working Safely in Science
• Before performing any activity in this
course, study the rules in the Science
Safety section of the Skills Handbook.
• Before you start the activity, read all the
steps.
1.2 Using a Scientific Approach
Science Skills
• Make sure that you understand the entire
procedure, especially any safety
precautions that must be followed.
• The single most important rule for your
safety is simple:
– Always follow the teacher’s instruction
and activity directions exactly.
1.3 Measurement
1.3 Measurement
Science Skills
1.3 Measurement
Science Skills
Using Scientific Notation
• Scientific notation is a way of expressing a
value as the product of a number between 1
and 10 and a power of 10.
• For example 300,000,000 can be written as
3.0 ×108.
– The exponent shows that the decimal
point is really 8 places to the right.
1.3 Measurement
Science Skills
• To show numbers less than 1 in scientific
notation, the exponent is negative.
– For example 0.00086 would be
8.6 ×10−4.
– The negative exponent tells how many
decimal places there are to the left of
the 8.6.
• Scientific notation makes very large or
very small numbers easier to work with.
1.3 Measurement
Science Skills
• When multiplying numbers in scientific
notation, you multiply the numbers before
the multiplication sign and add the
exponents.
• (3.0 ×108 m/s) (5.0 ×102 s) =
15 ×1010 =
1.5 ×1011 m
1.3 Measurement
Science Skills
• When dividing numbers in scientific
notation, divide the numbers before the
multiplication sign and subtract the
exponents.
• (1.5 ×1011 m) ÷ (3.0 ×108 m/s) =
0.50 ×103 s =
5.0 ×102 s
1.3 Measurement
Science Skills
SI Units of Measurement
• For a measurement to make sense, it
requires both a number and a unit.
• Scientists use a set of measuring units
called SI.
• The SI is a revised version of the metric
system, originally developed in France in
1791.
1.3 Measurement
Science Skills
Base Units
• SI is built upon seven metric units, known as
base units.
• The base unit for length is the meter (m).
• The base unit for mass is the kilogram (kg).
• Mass measures the quantity of matter in an
object.
1.3 Measurement
Science Skills
Derived Units
• Additional units, called derived units, are
made from combinations of base units.
• Volume, the amount of space taken up by
an object, has the unit m3.
1.3 Measurement
Science Skills
• Density is the ratio of an object’s mass to
its volume.
• Density = mass/volume.
• The unit for density is kg/m3.
1.1 What is Science?
Derived Units
Quantity
Unit
Symbol
Area
square meter
m2
Volume
cubic meter
m3
Density
kilogram per
cubic meter
kg/m3
Pressure
pascal (kg/m·s2)
Pa
Energy
joule (kg·m2/s2)
J
Frequency
hertz (1/s)
Hz
Electric charge
coulomb (A·s)
C
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1.3 Measurement
Science Skills
Metric Prefixes
• A metric prefix indicates how many times
a unit should be multiplied or divided by
10.
• See figure 15 on page 17.
• 12 km = 12 × 1000 m = 12,000 m
1.3 Measurement
Science Skills
• The easiest way to convert from one unit
of measurement to another is to use
conversion factors.
• A conversion factor is a ratio of equivalent
measurements that is used to convert a
quantity in one unit to another unit.
1.3 Measurement
Science Skills
Limits of Measurement
• Precision is a gauge of how exact a
measurement is.
• Significant figures are all digits that are
known in a measurement, plus the last
digit that is estimated.
• The fewer significant digits, the less
precise the measurement is.
1.3 Measurement
• When you make calculations with
Science Skills
measurements, the uncertainty of the
separate measurements must be correctly
reflected in the final result.
• The precision of a calculated answer is
limited by the least precise measurement
used in the calculation.
1.3 Measurement
Science Skills
• For example, a piece of iron has a mass of
34.73 g and a volume of 4.42 cm3.
• The density is mass divided by volume, so
for the iron, density would be
34.73 g / 4.42 cm3 = 7.857466 g/cm3.
• But the volume only has three significant
figures so the best answer is 7.86 g/cm3.
1.3 Measurement
• Accuracy is the closeness of a
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measurement to the actual value of what
is being measured.
1.4 Presenting Scientific Data
Science Skills
1.4 Presenting Scientific Data
• Scientific data become meaningful only
when they are organized and
communicated so other scientists can
understand them.
1.4 Presenting Scientific Data
Science Skills
Organizing Data
• Scientists can
•
organize their data by
using data tables and
graphs.
The simplest way to
organize data is to
present them in a
table.
City
Precip (cm)
Buffalo
98.0
Chicago
91.0
Houston
117.0
San Diego
25.1
Tallahassee 166.9
1.4 Presenting Scientific Data
Science Skills
Line Graphs
• A line graph is useful for showing changes
that occur in related variables.
• In a line graph, the manipulated (or
independent) variable is generally plotted
on the horizontal, or x-axis.
• The responding (or dependent) variable is
plotted on the vertical, or y-axis.
1.4 Presenting Scientific Data
Science Skills
• Figure 21 shows how mass of water
increases with volume.
• The steepness, or slope, of the line is the
ration of a vertical change to the
corresponding horizontal change.
• The formula for slope of a line is “rise over
run.”
1.4 Presenting Scientific Data
Science Skills
• A direct proportion is a relationship in
which the ratio of two variables is constant
like in figure 21.
• Figure 22 illustrates an inverse proportion
in which the product of two variables is a
constant.
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1.4 Presenting Scientific Data
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Bar Graphs
• Bar graphs (see figure 23) are used to
compare a set of measurements,
amounts, or changes.
• The bar graph makes it easy to see how
the data for one measurement compare
with data for another.
1.1 What is Science?
Science Skills
1.4 Presenting Scientific Data
Science Skills
Circle Graphs
• A circle graph (see figure 24) is a divided
circle that shows how a part or share of
something relates to the whole.
• Each slice of the circle represents a
percentage corresponding to a specific
measurement.
1.1 What is Science?
Science Skills