Ch 1 Science Skills
Science involves
asking questions
about nature and
then finding
ways to answer
them.
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Branches of Science
Natural science is generally divided into three branches:
physical science, Earth and space science, and life science.
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Physical science focuses on
nonliving things.
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.
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Scientific Method
There is no one absolute
“Scientific Method”-it is
simply a list of general
steps scientists take to
solve problems or answer
questions
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1) Come up with a question…
The heart of science is looking
around you and wondering
-how…?
-why…?
-what if…?
The question should be answerable
by performing an experiment.
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2) Create a hypothesis-one
possible answer to your question…
A hypothesis is an
educated statement or
guess about how
something works that
can be proven right or
wrong by performing
an experiment.
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3) Design an experiment…
Think of how you can test
your hypothesis. Usually,
you only want to test one
thing or one variable at a
time.
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4) Perform experiment and collect
data…
Perform the experiment
you designed . Observe
and record what
happens in as much
detail as possible!
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5) Draw conclusions…
Sometimes it is not clear
what the results of the
experiment were.
Often repeating the
experiment or designing
another one is necessary.
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6) Communicate your results…
*Scientists around the world
cooperate and share their work so
that others can benefit from what
they’ve learned.
*Other scientists look at the work
to see if they agree in a process
called peer review.
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Testing a Hypothesis
In an experiment, any factor that can change is
called a variable.
• The manipulated/independent variable causes a
change.
• The responding/dependent variable changes in
response to the manipulated variable.
• A controlled experiment is an experiment in which
only one variable, the manipulated variable, is
deliberately changed at a time.
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Theories vs. Laws of science
A scientific theory is a well-tested explanation for a set of
observations or experimental results. Once a hypothesis has
been supported in repeated experiments, scientists can
begin to develop a theory.
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. A scientific law describes an observed
pattern in nature without attempting to explain it. The
explanation of such a pattern is provided by a scientific
theory.
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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, the speed of light is about
300,000,000 meters per second. In scientific
notation, that speed is 3.0 × 108 m/s. The
exponent, 8, tells you that the decimal point
is really 8 places to the right of the 3.
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For numbers less than 1 that are written in
scientific notation, the exponent is negative.
For example, an average snail’s pace is
0.00086 meters per second. In scientific
notation, that speed is 8.6 × 10-4 m/s.
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SI units of measurement
Base Units and Derived Units
SI is built upon seven metric units, known as base
units.
• In SI, the base unit for length, or the straight-line
distance between two points, is the meter (m).
• The base unit for mass, or the quantity of matter in an
object or sample, is the kilogram (kg).
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 Seven
metric base
units make
up the
foundation
of SI.
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Additional SI units, called derived units, are made
from combinations of base units.
• Volume is the amount of space taken up by an object.
• Density is the ratio of an object’s mass to its volume:
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Metric Prefixes
The metric unit is
not always a
convenient one
to use. A metric
prefix indicates
how many times
a unit should be
multiplied or
divided by 10.
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Limits of measurements
 Precision is a gauge of how exact a measurement I
 Another important quality in a measurement is its
accuracy. Accuracy is the closeness of a measurement
to the actual value of what is being measured. s.
 For example, a more precise time can be read from the digital
clock than can be read from the analog clock. The digital clock
is precise to the nearest second, while the analog clock is
precise to the nearest minute.
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 Significant figures are all the digits that are
known in a measurement, plus the last digit that
is estimated.
 Whenever you work a problem in science you
need to keep significant figures in mind. Your
answer should have the same number of
significant figures as your knowns (the
information you were given)
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Measuring Temperature
The two temperature scales that you are probably
most familiar with are the Fahrenheit scale and the
Celsius scale.
• A degree Celsius is almost twice as large as a degree
Fahrenheit.
• You can convert from one scale to the other by using
one of the following formulas.
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 The SI base unit for temperature is the
kelvin (K).
 To convert between K And C use the
following formula;
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Presenting Data
 In order for news to be
useful, it must be reported
in a clear, organized
manner. Like the news,
scientific data become
meaningful only when they
are organized and
communicated.
Communication includes
visual presentations, such
as these graphs.
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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 x-axis.
• The responding variable is plotted on the vertical
axis, or y-axis, of the graph.
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Bar Graphs
A bar graph is often used to compare a set of
measurements, amounts, or changes.
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Circle or Pie graph
 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.
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