How can science provide
answers to your
questions about the
world around you?
Understanding Science
•  What is scientific inquiry?
•  What are the results of scientific
investigations?
•  How can a scientist prevent bias in a
scientific investigation?
Understanding Science
•  science
•  technology
•  observation
•  scientific theory
•  inference
•  scientific law
•  hypothesis
•  critical thinking
•  prediction
What is science?
•  Science is the investigation and
exploration of natural events and of the
new information that results from those
investigations.
•  People use reasoning, creativity, and
skepticism in their daily lives to solve
problems.
Branches of Science
Biology, or life science, is the study of all
living things.
biology
from Greek bios, means “life”;
and logia, means “study of”
Branches of Science (cont.)
•  The study of Earth, including landforms,
rocks, soil, and forces that shape
Earth’s surface, is Earth science.
•  The study of chemistry and physics is
physical science.
Scientific Inquiry
As scientists study the natural world, they
usually use certain skills, or methods.
Scientific Inquiry (cont.)
A scientist uses a sequence of skills and
methods in an investigation.
Scientific Inquiry (cont.)
•  Observations often are the beginning of
the process of science.
•  An observation is using one or more of
your senses to gather information and
take note of what occurs.
Scientific Inquiry (cont.)
•  A possible explanation about an
observation that can be tested by
scientific investigations is a hypothesis.
•  A prediction is a statement of what will
happen next in a sequence of events.
Scientific Inquiry (cont.)
•  When you test a hypothesis, you often
are testing your predictions.
•  If your prediction is not confirmed, your
hypothesis might need revision.
Scientific Inquiry (cont.)
•  The next step in a scientific investigation
is to organize and analyze your data.
•  You must determine whether inferences
can be made or conclusions drawn from
the data.
•  An inference is a logical explanation of
an observation that is drawn from prior
knowledge or experience.
•  If your hypothesis is supported by the
data, you can repeat the experiment to
confirm the results.
•  If your hypothesis is not supported, you
may need to modify it.
Scientific Inquiry (cont.)
An important step in scientific inquiry is
communicating results.
Results of Scientific Inquiry
•  In science, you perform scientific inquiry
to find answers to questions.
•  The practical use of scientific knowledge,
especially for industrial or commercial
use is technology.
•  Many times, scientific investigations
answer the questions: who, what, when,
where, or how.
Scientific Theory and Scientific Laws
•  A scientific theory is an explanation
of observations or events based on
knowledge gained from many
observations and investigations.
•  A scientific law describes a pattern or
an event in nature that is always true.
Scientific Theory and Scientific Laws
(cont.)
•  Critical thinking is comparing what you
already know with the information you
are given in order to decide whether you
agree with it.
•  To prevent bias in an investigation,
sampling, repetition, and blind studies
can be helpful.
Scientific Theory and Scientific Laws
(cont.)
•  Questions about personal opinions,
values, beliefs, and feelings cannot be
answered scientifically.
•  Scientists follow safety procedures when
they conduct investigations.
•  Ethics are especially important when
using living things during investigations.
Measurement and Scientific
Tools
•  What is the difference between
accuracy and precision?
•  Why should you use significant digits?
•  What are some tools used by
scientists?
Measurement and Scientific
Tools
•  description
•  accuracy
•  explanation
•  precision
•  International
System of
Units (SI)
•  significant digits
Description and Explanation
•  A description is a spoken or written
summary of observations.
•  An explanation is an interpretation of
observations.
•  When you explain something, you try to
interpret your observations, which can
lead to a hypothesis.
The International System of Units
•  The International System of Units (SI)
is an internationally accepted system for
measurement.
•  All SI units are
derived from seven
base units.
The International System of Units (cont.)
•  A prefix can be
added to a base
unit’s name to
indicate either a
fraction or a multiple
of that base unit.
•  Prefixes are based
on powers of ten,
such as 0.01 and
100.
•  Accuracy is a description of how close
a measurement is to an accepted or
true value.
•  Precision is a description of how
similar or close measurements are to
each other.
The data taken by student A are more
accurate because each value is close to
the accepted value. The data taken by
student C are more precise because the
data are similar.
Measurement and Accuracy
•  All measurements have some
uncertainty.
•  The tools used to make measurements
limit the accuracy of the measurements.
Significant Digits
•  Significant digits are the number of
digits in a measurement that are known
with a certain degree of reliability.
•  The significant digits in a measurement
include all digits you know for certain
plus one estimated digit.
Significant Digits (cont.)
Using significant digits lets others know
how certain your measurements are.
Scientific Tools
Science journals are for
recording descriptions,
explanations, plans, and
steps used in scientific
inquiry.
Corbis
Scientific Tools (cont.)
A triple-beam balance or
a digital balance is used
by scientists to measure
mass.
The McGraw-Hill Companies, Inc./Stephen Frisch, photographer
Scientific Tools (cont.)
A thermometer
measures the
temperatures
of substances.
The McGraw-Hill Companies Inc./Ken Cavanagh Photographer
Scientific Tools (cont.)
Flasks, beakers,
petri dishes, test
tubes, and specimen
jars are used as
containers.
Scientific Tools (cont.)
•  Graduated cylinders are
used to measure the volume
of a liquid.
•  The unit of measure for liquid
volume is the liter (L) or
milliliter (mL).
Scientific Tools (cont.)
Microscopes, such
as dissecting
microscopes and
compound light
microscopes,
enable you to
observe small
objects that you
cannot observe
with just your eyes.
Photodisc/Getty Images
Scientific Tools (cont.)
Scientists use computers to compile,
retrieve, and analyze data for reports.
Tools Used by Life Scientists
•  A magnifying lens is a hand-held lens
that magnifies, or enlarges, an image of
an object.
•  To observe items using a compound
light microscope, you must place it on a
thin, rectangular piece of glass called a
slide.
Tools Used by Life Scientists (cont.)
•  Scientists use
dissecting tools,
such as scalpels and
scissors, to examine
tissues, organs, or
prepared organisms.
Ingram Publishing/SuperStock
•  A pipette is a small
glass or plastic tube
used to draw up and
transfer liquids.
Photodisc Collection/Getty Images
Case Study
•  How do independent and dependent
variables differ?
•  variable
•  dependent variable
•  independent variable
•  constants
Designing a Controlled Experiment
•  Scientists use scientific inquiry to
investigate the use of protists to make
biodiesel.
•  They design controlled experiments to
test their hypotheses.
•  A controlled experiment is a scientific
investigation that tests how one variable
affects another.
Designing a Controlled Experiment
(cont.)
•  A variable is any factor in an experiment
that can have more than one value.
•  In controlled experiments, there are two
types of variables: dependent variables
and independent variables.
Designing a Controlled Experiment
(cont.)
•  The dependent variable is the factor
measured or observed during an
experiment.
•  The independent variable is the factor
that you want to test. It is changed by the
investigator to observe how it affects a
dependent variable.
Designing a Controlled Experiment
(cont.)
Constants are the factors in an
experiment that remain the same.
Designing a Controlled Experiment
(cont.)
•  A controlled experiment has two groups
—an experimental group and
a control group.
•  The experimental group is used to study
how a change in the independent
variable changes the dependent
variable.
•  The control group contains the same
factors as the experimental group, but
the independent variable is not changed.
The process of
scientific inquiry and
performing scientific
investigations can
provide answers to
questions about your
world.
Lesson 1: Understanding Science
•  Scientific inquiry, also known as scientific methods,
is a collection of skills that scientists use in different
combinations to perform scientific investigations.
•  Scientific investigations often result in new
technology, new materials, newly discovered objects
or events, or answers to questions.
•  A scientist can help prevent bias in a scientific
investigation by taking random samples, doing blind
studies, repeating an experiment several times, and
keeping accurate and honest records.
Lesson 2: Measurement and
Scientific Tools
•  Precision is a description of how similar or close
measurements are to each other. Accuracy is a
description of how close a measurement is to an
accepted value.
•  Significant digits communicate the precision of the
tool used to make measurements.
•  Life scientists use many tools, such as science
journals, microscopes, computers, magnifying
lenses, slides, and dissecting tools.