Buckle Down
3–4 Science
The Nature of Science
Review 1: Scientific Inquiry
Review 2: Collecting Data
Review 3: Reporting Results
Review 4: Science and Technology
Unit 2
Physical Science
Review 5: Physical Properties and Changes
Review 6: Energy
Review 7: Light and Sound
Review 8: Force and Motion
Unit 3
Earth and Space Science
Review 9: The Earth’s Water
Review 10: Weather
Review 11: Changes to the Earth’s Surface
Review 12: The Earth’s Resources
Review 13: Outer Space
Unit 4
Life Science
Review 14: Basic Needs of Living Things
Review 15: Classifying Organisms
Review 16: Life Cycles
Review 17: Fossils and Changing Habitats
Review 18: Connections Among Living Things
2ND EDITION
3–4
Science
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READING • WRITING • MATHEMATICS • SCIENCE • ALGEBRA I • BIOLOGY
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Student Set US02100S2
ISBN 0-7836-4969-X
5 1 4 9 5
Includes: Student Workbook, Form A
Practice Test, Form B Practice Test
Individual Products:
Student Workbook US02100W2
Form A Practice Test US02100A2
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9
780783 649696
3–4 SCIENCE
Scientists gather clues from fossils
to learn more about animals,
plants, and ecosystems that existed
millions of years ago. The picture
on the cover shows the fossils of two
Diictodons, a species that lived 250
million years ago.
Unit 1
TABLE OF CONTENTS
Introduction.................................................................................... 1
General Tips for Taking Science Tests........................... 2
Unit 1 – The Nature of Science.................................................. 5
Review 1: Scientific Inquiry............................................. 6
Science Standards and Concepts: NS.A.1–5, NS.B.1–3,
NS.B.6
Review 2: Collecting Data............................................ 18
Science Standards and Concepts: NS.A.5, NS.B.1,
NS.B.4, NS.B.5
Review 3: Reporting Results.......................................... 30
Science Standards and Concepts: NS.B.7–9
Review 4: Science and Technology............................. 44
Science Standards and Concepts: NS.C.1–4, NS.D.1–5
Unit 2 – Physical Science.......................................................... 55
Review 5: Physical Properties and Changes............... 56
Science Standards and Concepts: PS.A.1–4, NS.B.1
Review 6: Energy........................................................... 70
Science Standards and Concepts: PS.B.1, PS.B.2, NS.B.1
Review 7: Light and Sound........................................... 82
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Science Standards and Concepts: PS.B.1, PS.B.2, NS.B.1
Review 8: Force and Motion........................................ 92
Science Standards and Concepts: PS.C.1–4, NS.B.1
Unit 3 – Earth and Space Science........................................ 101
Review 9: The Earth’s Water...................................... 102
Science Standards and Concepts: ESS.A.1, ESS.A.2, NS.B.1
Review 10: Weather.................................................... 110
Science Standards and Concepts: ESS.A.3, NS.B.1
Review 11: Changes to the Earth’s Surface.............. 126
Science Standards and Concepts: ESS.B.1, ESS.B.2,
NS.B.1
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Table of Contents
Review 12: The Earth’s Resources.............................. 136
Science Standards and Concepts: ESS.B.3, ESS.B.4,
NS.B.1
Review 13: Outer Space............................................. 149
Science Standards and Concepts: ESS.C.1–3, NS.B.1
Unit 4 – Life Science................................................................. 161
Review 14: Basic Needs of Living Things.................. 162
Science Standards and Concepts: LS.A.1–3, NS.B.1
Review 15: Classifying Organisms............................. 171
Science Standards and Concepts: LS.A.3, LS.A.4
Review 16: Life Cycles................................................ 183
Science Standards and Concepts: LS.B.1–3, LS.C.4
Review 17: Fossils and Changing Habitats............... 193
Science Standards and Concepts: LS.C.1–4, LS.D.4,
NS.B.1
Review 18: Connections Among Living Things........ 204
Science Standards and Concepts: LS.D.1–3, LS.D.5
Appendix.................................................................................... 211
To the Teacher:
Science Standards and Concepts
codes are listed for each review in the
table of contents and for each page in
the shaded gray bars that run across
the tops of the pages in the workbook
(see the example at right). These codes
identify the Standards and Concepts
covered on a given page.
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Glossary....................................................................... 212
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Unit 1 – The Nature of Science
Science Standards and Concepts: NS.A.1, NS.A.3, NS.A.4, NS.B.1–3
Scientific Inquiry
From the time you wake up in the morning until you go to sleep at night, you are
asking questions and solving problems. In other words, you are inquiring. As you
go through the day, you will see many different puzzles in the world around you.
Each puzzle requires a different set of questions and its own solution. Science is
about inquiry, too. When you inquire, you ask questions to find out more about
your topic. To be a good scientist means you have to be a good inquirer. With
each new puzzle they see, scientists decide what questions to ask. Then they run
an investigation, or careful study, to try to answer their questions. As you’ll see
in this review, many kinds of questions help with scientific learning. You will learn
how to recognize scientific information and run your own scientific investigations.
Asking Questions
In order to ask the right questions, you need to be able to observe. An
observation is information you gather using your senses or through taking a
measurement. Once you make an observation, you can often make an inference.
An inference is an educated guess about how or why something happened. If
you come home and observe that your new shoes are all chewed up and have
teeth marks on them, then you might infer that the dog chewed up your shoes.
Words
to Know
claim
data
evidence
experiment
fact
hypothesis
inference
inquiry
investigation
observation
opinion
variable
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A scientific investigation is a controlled study of a natural event. When you
answer a riddle, you might not think about how your brain tries to answer it. In
a scientific investigation, however, it is important to think about the way we look
for answers. Asking the right question is the first step. Asking the right questions
helps you reach an answer.
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Review 1: Scientific Inquiry
Science Standards and Concepts: NS.A.1, NS.A.3, NS.A.4, NS.B.1–3
You don’t have proof that this is what happened, but you can guess that this is
probably what happened.
Scientists ask different types of questions depending on what kind of evidence
they’re looking for. When you begin a scientific investigation, it is a good
idea to ask big, open questions. These questions should be based on your
early observations of an event that interests you. Often, these will be Why
questions, such as Why is the sky blue? or Why do birds suddenly appear in the
springtime? Why questions are great for getting ideas.
Let’s look at one example of the beginning of a scientific investigation. In the
following paragraph, find the early observation and come up with a Why
question that could start a scientific investigation.
Last summer, Cliff spent a week with his grandparents, who live in
Louisville, Kentucky. Cliff enjoyed falling asleep to the sound of all the
crickets chirping. He noticed that the crickets chirped very quickly on
Tuesday night, but they chirped much more slowly on Wednesday night.
Observation: _______________________________________________
__________________________________________________________
Why question: ______________________________________________
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__________________________________________________________
Scientists use Why questions to start investigations, but those questions are
usually too general to use later on. Instead, they ask more specific questions
that can be answered by observing, measuring, or experimenting. These kinds
of questions often begin with What happens when . . . ? or How many . . . ?
or Where are . . . ? Asking these questions will help you design experiments,
which are investigations that see how things affect each other. Questions also
help you explain your observations.
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Unit 1 – The Nature of Science
Science Standards and Concepts: NS.A.1, NS.A.3, NS.A.4, NS.B.1–3
Good scientists are also open-minded. They are able to change their ideas
about how the world works when they learn something new. Plus, you must be
able to ask questions about things that you think you already know. For example,
most people used to think the world was flat. If everyone just accepted this idea,
we might still think that way today. Instead, many people began to question the
idea, and they soon showed that the world is round.
Whenever you hear or read explanations of scientific ideas, ask more questions!
Asking questions doesn’t mean you don’t believe whoever is giving the
explanation. It means that you are curious and want to know more. If someone
makes an observation, compare it with your own observations. If the observation
sounds different in some way, ask questions to find out about the differences. For
an example of this kind of questioning, read the following conversation between
two fourth graders.
Now, even though A.J. was surprised by Allie’s claim, he didn’t say that it was
impossible for rain to burn through metal. Instead, he asked questions. He
compared Allie’s strange idea with his own observations, and this led him to ask
even more questions. Finally, Allie didn’t pretend to know why it rains acid on
Venus: She left it open for more questions. The more questions you ask about the
world around you, the better you’ll be able to understand the world.
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“I just read about a place where the rain is an acid that can burn through
metal,” said Allie.
“No way!” cried A.J. “Where?”
“On the planet Venus,” replied Allie.
“How is that possible?” said A.J. “Here on Earth, rain is made of water.”
“I’m not sure,” shrugged Allie. “It’s got something to do with the fact that
Venus is a lot hotter than Earth.”
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Review 1: Scientific Inquiry
Science Standards and Concepts: NS.A.1–4, NS.B.1, NS.B.6
Starting Your Investigation
You make decisions every day, whether it’s deciding what to wear to the
softball game or deciding where to sit in science class. You probably base
your decisions on certain things. Scientists make decisions every time they have
an investigation. They base their decisions on a few different things. They use
evidence, or clues, they have gathered. They also make decisions based on
what they already know about the topic they are studying. Lastly, they use
the claims of others if those claims are based on solid evidence. A claim is a
statement someone wants us to believe is true.
Scientists, then, do the same thing you do when you sort out facts from opinions.
A fact is a piece of information that can be proven to be true. We say that facts
have been established, which means that they have been proven again and
again. Opinions, on the other hand, cannot be proven; they are statements
about one’s personal feelings. Opinions are important, but they cannot be the
basis of scientific knowledge.
Read the following statements. On the lines provided, write down whether each
statement is a fact or an opinion, and explain why you think so.
The population of Minneapolis, MN, in 2005 was about 372,800 people.
__________________________________________________________
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__________________________________________________________
Yellowstone National Park is the best place to go hiking in the United
States.
__________________________________________________________
__________________________________________________________
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Unit 1 – The Nature of Science
Science Standards and Concepts: NS.A.1–4, NS.B.1, NS.B.6
An important step in scientific investigations is coming up with the right questions
to ask. Good questions help scientists focus their investigations. A hypothesis
is a question or a statement about the natural world that can be scientifically
tested. It is similar to a prediction, which is when you make an educated guess
at what will happen. It is important to note that a hypothesis must be testable.
In other words, you must be able to find an answer through testing and
experimenting, but it doesn’t necessarily have to be correct.
Are the following hypotheses testable? Explain why or why not.
The average heartbeat of a hobbit at rest is 52 beats per minute.
__________________________________________________________
__________________________________________________________
Grasshoppers chirp more frequently as the temperature rises.
__________________________________________________________
__________________________________________________________
The Earth is flat.
__________________________________________________________
In an investigation, a scientist will often change the hypothesis after observing
the first set of results. The new hypothesis might lead to a different type of
investigation, which produces new data, or information. Again, the new results
are compared to the hypothesis, and the hypothesis might be changed a second
time. This cycle can repeat itself many times, until the scientist finds a hypothesis
that predicts the results of the investigation. Incorrect hypotheses can still help an
investigation, because they help investigators improve their ideas.
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__________________________________________________________
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Review 1: Scientific Inquiry
Science Standards and Concepts: NS.A.1–5, NS.B.1–3, NS.B.6
Variables are factors that can change the results of an experiment. There are
many variables that can affect an experiment, and it is difficult to account for all
the variables. For example, if two motor boats are racing, factors such as wind
speed and direction, type of motor, and the experience of the driver are all
variables that will affect how the race turns out. Scientists must often change their
hypotheses and repeat experiments because they encounter variables.
If you are growing a potted plant, what variables could you change that
might affect how quickly or how tall the plant grows?
__________________________________________________________
__________________________________________________________
__________________________________________________________
Experimenting
You have already learned about the first three steps of scientific inquiry: 1. observing natural events and making general statements about them,
2. asking broad questions about the event to focus your mind, and
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3. coming up with a testable hypothesis.
Science is all about finding the patterns in nature, so you want to end up with a
hypothesis that can make predictions about those patterns. That’s what step 4 is
about: 4. Make a prediction based on what you think will happen.
5. In step 5, you run an experiment and see whether your prediction was
correct.
In most experiments, the first hypothesis did not predict things perfectly. This
is normal. When this happens, you change your hypothesis to fit the new
observations and then run the experiment again. The best scientific investigations
go through this process many times. Repeating experiments is the only way to
get hypotheses that work really well at predicting natural patterns.
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Unit 1 – The Nature of Science
Science Standards and Concepts: NS.A.1, NS.A.3–5, NS.B.1–3
Hank wrote the following hypothesis in his notebook: “Magnets attract
metal objects.” During his experiment, however, Hank found that magnets
do not attract aluminum cans or copper wire. How would you change
Hank’s hypothesis to continue the investigation?
__________________________________________________________
__________________________________________________________
__________________________________________________________
__________________________________________________________
Keys to Keep
Ask “why” questions to find out more about a scientific
investigation.
Think about the ways in which you an investigate a topic. Come up
with a plan for your experiment.
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R
emember that a hypothesis can be wrong. Do not be discouraged
if your experiment does not produce the results that you expected.
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Review 1: Scientific Inquiry
Science Standards and Concepts: NS.A.1, NS.A.4, NS.B.1, NS.B.2
Explore It Yourself
The purpose of this activity is to show how important it is for a scientist to gather
accurate information and then use that information.
In this exercise, you will do some simple tests on glass beakers that contain
water. You will need five 600-mL beakers (all the same size and shape), a
graduated cylinder, a metal teaspoon, and some water. You will need a partner
for this activity.
Step 1: Fill the five 600-mL beakers with the following amounts of water:
100 mL, 150 mL, 300 mL, 400 mL, and 450 mL.
Step 2: Each of the beakers will make a different sound when it is tapped lightly
on the side by the metal spoon. Do you think the beaker with 100 mL
of water in it will make a higher-pitched sound than the beaker with
400 mL of water in it? Why do you think so?
________________________________________________________
________________________________________________________
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________________________________________________________
Step 3: Use the metal spoon to lightly tap the beaker with 100 mL of water and
the beaker with 400 mL of water. Notice the difference in the sounds
made by the two beakers. Which beaker has the higher pitch when
tapped?
Amount of Water
in Beaker (mL)
High Pitch or
Low Pitch
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Unit 1 – The Nature of Science
Science Standards and Concepts: NS.A.1, NS.A.4, NS.B.1, NS.B.2
Step 4: If two identical beakers have different amounts of water in them, will
the beaker with more water make a higher-pitched sound or a lowerpitched sound than the beaker with less water?
________________________________________________________
________________________________________________________
________________________________________________________
________________________________________________________
Step 5: Have your partner sit facing away from the beakers so that he or she
cannot see them. Lightly tap the other three beakers with the metal
spoon. Ask your partner if he or she can tell a difference in the pitch of
the sounds made by the beakers.
Step 6: If your partner can tell a difference in the sounds, tap the beakers again
with the metal spoon. Ask your partner to tell which beaker has 150 mL
of water, which beaker has 300 mL of water, and which beaker has
450 mL of water. Write your partner’s guess on the lines below.
________________________________________________________
________________________________________________________
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________________________________________________________
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Review 1: Scientific Inquiry
Science Standards and Concepts: NS.A.1, NS.A.4, NS.B.1, NS.B.2
What Does It Mean?
1. Why did your partner need to listen to the first two beakers being tapped
before listening to the other beakers being tapped?
__________________________________________________________
__________________________________________________________
__________________________________________________________
__________________________________________________________
2. In Step 4, you said how the amount of water affects the pitch. If you were
wrong in Step 4, how would that affect your answer to Step 6?
__________________________________________________________
__________________________________________________________
__________________________________________________________
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__________________________________________________________
3. A 600-mL beaker with 200 mL of water in it will make a lower-pitched
sound than a 250-mL beaker with 200 mL of water in it. If you had a
1,000-mL beaker with 200 mL of water in it, would it make a sound higher
or lower than the 600 mL beaker with 200 mL of water in it? How do you
know this?
__________________________________________________________
__________________________________________________________
__________________________________________________________
__________________________________________________________
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Unit 1 – The Nature of Science
Science Practice
1. Scientists ask questions that can be answered with facts. Which of
the following is not a scientific question that a scientist might try to
answer?
A. How many frogs are in a pond?
B. How do birds learn their songs?
C. Are skateboards more fun than bicycles?
D. Which plant needs more water to live?
2. A hypothesis is an idea that can be tested by observation and
experiment. Which of the following is the best example of a
hypothesis?
A. Owls are the meanest birds in all the forest.
B. A rabbit’s diet affects how fast it runs.
C. Albert Einstein was probably the smartest scientist of all time.
3. Which of the following is an inference?
A. The drought probably caused that plant to die.
B. Honolulu is the capital of Hawaii.
C. Humans are vertebrates.
D. A panda’s main food source is bamboo.
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D. There is no way to improve the way that science is done.
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Review 1: Science Practice
4. Tamika did an experiment and got one set of results. She did the
same experiment again and got very different results. What should
Tamika do next?
A. Ignore the results of the second experiment.
B. Decide that there were mistakes in the first experiment.
C. Give up on the experiment and perform a new one.
D. Repeat the experiment and compare all three sets of results.
5. What is a claim?
A. a law of nature that everyone knows
B. a clue that helps you solve a problem
C. an animal with a two-piece shell that lives in the water
D. a statement that someone wants you to believe is true
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6. Jackie and James each have a different remote control car. They
want to run an experiment to see which car is faster. If they are
given equal driving conditions, which of the following is not a
variable that might favor one car over the other?
A. the person driving
B. the texture of the driving surface
C. the size of the wheels
D. the amount of battery power available
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