KEY CONCEPT
Basic tools of science
are universal.
Sunshine State
STANDARDS
SC.H.1.3.2: The student
knows that the study of
the events that led scientists to discoveries
can provide information
about the inquiry process and its effects.
SC.H.1.3.3: The student
knows that science disciplines differ from one
another in topic, techniques, and outcomes,
but that they share a
common purpose, philosophy, and enterprise.
SC.H.1.3.6: The student
recognizes the scientific
contributions that are
made by individuals of
diverse backgrounds,
interests, talents, and
motivations.
BEFORE, you learned
NOW, you will learn
• Scientists collect evidence by
making observations
• Scientific results must be
reproducible
• Scientists record and share
results
• How people use scientific
processes
• About scientific habits of mind
• How scientists build up scientific
information
EXPLORE Observations and Opinions
How are observations different from opinions?
MATERIALS
PROCEDURE
1
Fill the bottles one-third full with water.
2 Add one spoonful of a different type of
cleaning product to each bottle. Fasten the lids
tightly and shake each bottle for 15 seconds.
•
•
•
•
3 bottles with lids
water
spoon
3 types of
cleaning
products
3 Observe the suds in each bottle.
WHAT DO YOU THINK?
VOCABULARY
scientific processes p. 6
hypothesis p. 7
creative thinking p. 8
skepticism p. 9
critical thinking p. 10
How is comparing the heights of suds produced by the cleaning
products different from comparing how good they smell?
Science is a way to study the natural world.
People continually ask questions, explore ideas, and reach conclusions.
Sometimes scientific methods can help them, but not all questions can
be answered scientifically. For example, suppose people are deciding
which musicians to invite to perform in the town’s park. They may
discuss their opinions vigorously, but science cannot help them make
the best choice.
What can be studied scientifically? Anything that can be observed
objectively and that involves features of the natural world. Objective
observations are the same for everyone. For example, choosing the
best type of grass to plant in the park can be approached scientifically.
People can test varieties of grass to find out which would grow well in
the park and withstand being walked on by large numbers of concertgoers. The grasses are part of the natural world, their growth can be
tested, and different observers will get similar results.
Chapter 1: The Nature of Science 5
Different sciences use similar processes.
FLORIDA
Content Review
Remember what you
learned in grade 6 about
scientific thinking. See
pages R2–R9 for a reminder.
Content Review
reading tip
The word inquiry means
a search for information
or truth.
Suppose you asked a group of scientists to describe in one word what
they study. Each person would probably name a specific area of science.
Because science is the study of the natural world, you could get as many
answers as there are aspects of the universe. The pictures below show
a few of the many types of science.
All scientists, no matter what topics they study, use the same processes when they make their scientific inquiries. As you will read in
Section 2, inquiries can include experiments and other ways of gathering data. An inquiry usually involves these scientific processes:
•
asking questions
•
interpreting results
•
determining what is known
•
sharing information
•
investigating
Some of the Types of Science
A scientific study can often be classified as life science, physical science, or
earth science. Some types of studies fall into two or more categories.
Geology is the study of Earth’s surface and
interior. This scientist examines glowing molten
rock from a volcano.
Chemistry is the
study of the properties and interactions
of substances. This
scientist has
purified a liquid
by removing certain
substances from it.
Physics is the
study of energy
and matter. This
scientist uses
three special
microscopes to
understand and
change the surface of a material.
Biology is the study of living things. This scientist
tests materials that can be useful in human organ
transplants.
6 Chapter 1: The Nature of Science
The list of processes may look like a simple, logical series of steps.
However, science seldom follows such a rigid format. Results often
lead to new questions. An investigation may include several cycles of
observing, thinking of possible explanations, and making new observations to test the explanations. Steps can occur in any order, and
some may be repeated many times during a scientific inquiry.
For example, suppose you want to identify a beetle like the one
shown below. You might first observe the beetle. Investigating usually
includes observing, or gathering data. You can use instruments and
tools as well as your senses to gather data. You can make measurements to get quantitative data. Perhaps you estimate the size of the
beetle and record its color.
check your reading
reminder
Quantitative data are observations that include a
number or an amount.
How are measurements related to observations?
To identify the beetle, you need to compare your observations with
what is already known. You might use the descriptions and illustrations
in a field guide. You will likely need to make more observations and
comparisons before you can identify the beetle. The descriptions in the
guide might lead you to questions about the beetle’s life cycle or its
usual food. Often an answer to one question leads to new questions.
Investigating also means thinking about observations. Scientists
commonly develop and test several hypotheses. A hypothesis is a tentative explanation for a set of observations. A hypothesis can be written
in the form of an “If . . . , then . . . , because . . .” statement—for example, “If I drop a book, it will fall to the ground, because gravity acts on
it.” The first part of the statement describes a possible process or
event: dropping a book. The second part states a prediction that can
be tested by observation: the book will fall. The third part
explains why the predicted event should occur: gravity acts
on the book. The explanation may state a cause and
effect, or it may just describe a general pattern, such
as “Clearer nights are colder.” Often, scientists need
to make observations and apply what they know
before they can develop and test hypotheses.
An important part of a scientist’s inquiry is the sharing of methods, results, and conclusions. Scientific results
must be reproducible—possible to repeat. Other people
need to be able to duplicate the process and get similar
outcomes. Results and conclusions are accepted into the
body of scientific knowledge only when many people have
tested them. For example, scientists had to observe the
same characteristics in many beetles of a certain type
before the information could be put into a field guide.
Chapter 1: The Nature of Science 7
Scientists develop certain habits of mind.
MAIN IDEA WEB
Record in your notebook
important information
about scientific habits
of mind.
Anyone can take a scientific approach to a question. People who conduct scientific inquiries develop certain habits of mind. They learn to
be observant, curious, creative, and skeptical. They think critically.
Being Observant and Curious
Observant people pay attention to the world around them. They think
and ask questions about what they observe. Curiosity leads people to
explore different questions. Scientific questions are sometimes called
problems. Used in this way, the word problem refers to something to
be solved, like a puzzle. Curious people solve problems.
For example, Jocelyn Bell and Anthony Hewish
were studying radio waves from space. They were
using a huge pattern of wires held in place on poles.
In 1967 Bell was collecting and looking at data.
She needed to find the parts of the data that came
from space. To do this, she needed to identify and
eliminate signals from human activities.
Jocelyn Bell and Anthony
Hewish strung wires on
poles in order to detect
radio waves from space.
They discovered pulsars,
stars that seem to pulse
as they spin.
Bell was looking at data in the form of a graph,
like the line on a heartbeat monitor. Different types
of signals had different shapes. Bell compared the data
with the shapes of sources she knew. She observed
something odd. One signal was a repeating group of
fast pulses, or bursts. It was similar to some familiar
signals from human activities. However, Bell found differences. She was
curious about the differences and not sure that the signals came from
human activity. She decided to keep investigating what the source was.
Being Creative
You may not usually think of scientists as creative, but creative
thinking is an important source of ideas, questions, and explanations.
Creative thinking is a way to play with ideas to solve problems. For
example, Bell had to think of different possible sources for the radio
pulses, as well as ways to test her ideas.
Creative thinking takes practice. People think creatively by combining and expanding ideas in fresh ways. The more they know, the
more easily they can find the ideas to put together. Sometimes people
get together and share the ideas they have. Most of the ideas are later
rejected, but one wild idea may inspire a useful inquiry. This process
is called brainstorming. At other times, a person keeps a problem in
mind while doing other things. New ideas can come from seeing
something ordinary in a new way.
8 Chapter 1: The Nature of Science
Being Skeptical
Scientists accept uncertainty. They often work on problems to which
nobody yet knows the answers. Scientists think of many ideas, but
they don’t trust their ideas right away. Skepticism is the refusal to
accept an idea that is not backed up by evidence. Skeptical people
doubt and question. They learn to be comfortable with not knowing
for sure. They are willing to test their own ideas, to draw tentative
conclusions, and to change their minds. Sometimes people think that
a skeptic refuses to believe anything. Actually, a skeptic evaluates ideas
and accepts them if the evidence is good enough. A skeptic requires
unusual ideas or claims to have strong supporting evidence before
putting trust in them.
Check Your Reading
reading tip
The words skepticism and
skeptic both come from the
Greek word skeptikos,
which means “to examine.”
A skeptic is a person who
displays skepticism.
When is a skeptic willing to accept an idea?
For example, Bell had doubts that the radio pulses came from
human activity. She was skeptical. Eventually she and Hewish determined that the signal came from a location in space. Could the signal
be a communication from aliens? Bell and Hewish didn’t believe it
could be. They would have needed a great deal of evidence to convince
themselves. However, they tested the data to be sure. When they analyzed
their results, they became confident enough to reject the idea of aliens
as the source.
Solving Problems
SKILL FOCUS
PROCEDURE
1
Evaluating
Study the photograph. It shows a paper clip
that appears to be floating in air, held only by a
thread attached to its bottom.
MATERIALS
• paper clip
• thread
• other materials
as needed
2 Brainstorm ideas to explain why the paper clip
seems to be floating in air.
3 Use skepticism to eliminate some possible explanations. Use your best ideas
to determine how you might reproduce the setup in the photograph.
TIME
20 minutes
4 Request materials you need from your teacher, and test your ideas.
WHAT DO YOU THINK?
• How did you use creative thinking and skepticism?
• How many ideas did you test? How many people contributed
to the process?
CHALLENGE Brainstorm another way to reproduce the setup
in the photograph.
Chapter 1: The Nature of Science 9
VOCABULARY
Add a magnet word
diagram for critical thinking
to your notebook.
Thinking Critically
Skepticism is one part of critical thinking. Critical thinking is a
method of analysis that depends on logic, or correct reasoning.
It includes different skills that can help you find answers.
Big problems are often made of small, solvable
parts. You analyze something when you break it down into smaller
parts and examine how the parts are related. Bell analyzed her data
by breaking it into signals from different sources.
Analyze and Relate
Many problems are similar to other problems.
You can look for similarities to problems that have already been solved.
Differences between problems can alert you to differences in their
answers. Bell compared the pulses with signals from sources on Earth.
The differences made her look for a new source.
Compare and Contrast
Some problems are solved by connecting two or
more pieces of knowledge that, at first, may not seem related. Often,
you must take general knowledge and apply it to a specific situation.
Hewish connected the idea of Earth’s
motion to the radio signals. He applied
his knowledge to figure out how the
pulses would be different if they had
come from a source on Earth.
Connect and Apply
When you have
several related examples, you can sometimes infer a general rule. Or you might
be able to use logic to combine pieces of
information to infer new information.
Bell thought she saw a second signal
similar to the first. She used existing
data to infer the timing of the repeating
signal. She used this as a hypothesis and
tested it by looking for the signal at the
right time. She found it.
Infer and Hypothesize
This pulsar image combines
data from two different telescopes. The jet at the lower left
shows where the pulsar gives
off a narrow beam of energy.
Observers can detect pulses of
energy as the star spins.
Different parts of a problem, such as evidence,
inferences, and possible actions, should be examined and judged carefully, or evaluated. With enough reasons or convincing evidence, you
might draw a conclusion. Bell evaluated two more sets of signals. When
she had enough evidence, she concluded that they were from the same
types of things. She did not have enough information to know what
the things were. You will often use several skills together. You might
make a general hypothesis and then apply it to a particular situation in
order to predict an outcome. You might use other combinations.
Evaluate and Conclude
Check Your Reading
10 Chapter 1: The Nature of Science
What are some critical-thinking skills? Make a list.
Scientists build on previous knowledge.
While scientists are still working on problems, they may share their
work with other scientists. They may talk about their results and ideas
informally or present them at scientific conferences. The scientists
might give talks—perhaps multimedia presentations—or make
posters showing their early results. Other scientists can ask questions
or challenge the methods being used. These actions often lead to new
ideas and better approaches to the problems.
Scientists get together at
conferences to share their
work. Results may also be
reported in the news or
may be used to develop
new laws.
When Bell and Hewish thought they had enough
information, they shared their results. Other scientists
made additional observations, which led to an
explanation—a cause that accounted for the observed
effect. Bell and Hewish had discovered pulsars, which
are stars that give off narrow beams of energy, including radio waves. The energy is detected in pulses
because the stars rotate. The beams sweep around
like flashing lights on emergency vehicles. Scientists
later connected the beams of energy with other features, such as the jets in the image on page 10.
Changing Ideas
Scientists have to be willing to change their ideas. Many problems are
solved by challenging assumptions—ideas accepted as true without
evidence. For example, someone might assume that it would be foolish to coat oranges with ice to protect them from frost. However,
when the air temperature drops to slightly below freezing, spraying
water on crops such as oranges can save them from frost damage. As
water freezes, it releases heat energy into the fruit. The ice also protects the fruit from colder air.
Spraying fruit with water
during cold weather may
seem strange at first.
However, it makes sense
when you understand
how energy is transferred.
Chapter 1: The Nature of Science 11
Evaluating Conclusions
Scientists evaluate one another’s work. When scientists finish an
inquiry, they write a scientific paper describing their methods, results,
and conclusions. They send the paper to a scientific journal. The
journal’s editors send the paper to other scientists for review. Only
when the work has been checked and corrected does the journal publish the paper.
Scientists can build on
one another’s work only
when that work is shared.
Papers are evaluated by
other scientists before
being published in scientific journals.
A scientist relies on experience and training to evaluate the information and conclusions in a scientific paper. As part of everyday life,
you evaluate conclusions too. You use your personal experience to
figure out whether they are trustworthy. You might ask whether a
conclusion was reached by someone who understands the topic. You
might judge how well the evidence supports the conclusion. You would
be skeptical if no evidence were presented. You might also doubt a
conclusion presented by someone who would benefit from the acceptance of it. For example, a study in favor of a certain product might
not be trustworthy if paid for by a manufacturer who wanted to sell
that product.
Scientific conclusions can be supported by evidence, but they
are never considered to be proved. Science is an ongoing process.
Some amount of uncertainty is always present. Any conclusion can
be overturned if new evidence clearly shows it to be wrong. This
ability to change is a great strength of science. When scientists make
mistakes or their understanding is not complete, the work of other
scientists sooner or later corrects the ideas and expands the body of
scientific knowledge.
KEY CONCEPTS
CRITICAL THINKING
1. What processes do scientists
use?
4. Compare and Contrast
How are creative thinking
and critical thinking similar?
How are they different?
2. Choose one of the habits of
mind that scientists develop
and explain how it is useful in
an inquiry.
3. How is new scientific information checked and evaluated?
12 Chapter 1: The Nature of Science
5. Infer Why do scientists need
to learn to be comfortable
with uncertainty?
CHALLENGE
6. Provide Examples Choose
two of the critical-thinking
skills and show how you have
already used them in your
everyday life.