Table of Contents
Introduction to MSA Finish Line Science 8 . . . . . . . . . . . . . . . . . . . . . . . . 5
UNIT 1 The Practice of Science. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7
Lesson 1 How Scientists Do Science [1.A.1.a, c, g; 1.B.1.a; 1.C.1.e] . . . . . . . . . . . . . . . . . . 8
Lesson 2 Designing Experiments [1.A.1.e; 1.B.1.b] . . . . . . . . . . . . . . . . . . . . . . . . . . . . 15
Lesson 3 Presenting Scientific Data [1.A.1.h; 1.C.1.a] . . . . . . . . . . . . . . . . . . . . . . . . . . 21
Lesson 4 Interpreting Scientific Data [1.B.1.d; 1.C.1.b] . . . . . . . . . . . . . . . . . . . . . . . . . 27
Lesson 5 Skepticism in Science [1.B.1.e; 1.C.1.d] . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 32
The Practice of Science Review . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 38
UNIT 2 The Science of Earth and Space, Part 1 . . . . . . . . . . . . . . . . . . . 45
Lesson 1 Rocks and Minerals [(6)2.A.4.d; (8)2.B.1.a] . . . . . . . . . . . . . . . . . . . . . . . . . . . . 46
Lesson 2 Weathering [(6)2.A.2.c] . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 52
Lesson 3 Studying Earth’s Past [(8)2.B.1.b; (8)2.B.2.b] . . . . . . . . . . . . . . . . . . . . . . . . . . . 57
Lesson 4 Earth’s Structure [(6)2.C.1.a, b, c] . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 63
Lesson 5 Plate Tectonics [(8)2.B.1.a; (6)2.C.2.a, b] . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 68
The Science of Earth and Space, Part 1 Review . . . . . . . . . . . . . . . . . . . . . . . . . . . . 74
UNIT 3 The Science of Earth and Space, Part 2 . . . . . . . . . . . . . . . . . . . 87
Lesson 1 The Water Cycle [(8)2.E.1.b] . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 88
Lesson 2 Weather [(8)2.E.3.a, b] . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 94
Lesson 3 Climate [(8)2.E.1.c] . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 99
Lesson 4 Our Solar System [(6)2.D.1.a, c; (8)2.D.2.a, b; (8)2.D.3.b] . . . . . . . . . . . . . . . . . . 105
Lesson 5 Earth and the Moon [(8)2.D.2.c] . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 110
The Science of Earth and Space, Part 2 Review . . . . . . . . . . . . . . . . . . . . . . . . . . . 116
UNIT 4 The Science of Life, Part 1 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 119
Lesson 1 Classification of Life [(7)3.A.1.b] . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 120
Lesson 2 Animals [(7)3.A.1.a, c] . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 126
Lesson 3 Plants [(7)3.A.1.a, c] . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 131
The Science of Life, Part 1 Review . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 137
UNIT 5 The Science of Life, Part 2 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 140
Lesson 1 Levels of Organization [(7)3.B.1.b, c, d; (7)3.B.2.a] . . . . . . . . . . . . . . . . . . . . . 141
Lesson 2 The Circulatory and Respiratory Systems [(7)3.B.2.b] . . . . . . . . . . . . . . . 147
Lesson 3 The Skeletal and Muscular Systems [(7)3.B.2.b] . . . . . . . . . . . . . . . . . . . . 152
Lesson 4 The Digestive and Excretory Systems [(7)3.B.2.b] . . . . . . . . . . . . . . . . . . . 158
Lesson 5 The Nervous and Immune Systems [(7)3.B.2.b] . . . . . . . . . . . . . . . . . . . . 163
Lesson 6 The Endocrine and Reproductive Systems [(7)3.B.2.b] . . . . . . . . . . . . . . 170
The Science of Life, Part 2 Review . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 177
UNIT 6 The Science of Life, Part 3 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 178
Lesson 1 Asexual and Sexual Reproduction [(7)3.C.1.a, b, e] . . . . . . . . . . . . . . . . . . 179
Lesson 2 Natural Selection [(6)3.D.1.a, c, e; (8)3.D.1.b] . . . . . . . . . . . . . . . . . . . . . . . . . 184
Lesson 3 Change Over Time [(6)3.D.1.a, c, e; (8)3.D.1.a, b] . . . . . . . . . . . . . . . . . . . . . . . 190
Lesson 4 Photosynthesis [(7)3.E.1.c, d] . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 195
Lesson 5 Food Chains and Webs [(7)3.E.1.b, f] . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 201
Lesson 6 Ecosystem Resources [(6)3.F.1.a, c; (6)3.D.1.b] . . . . . . . . . . . . . . . . . . . . . . . . 206
The Science of Life, Part 3 Review . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 212
UNIT 7 The Science of Chemistry . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 215
Lesson 1 Elements and the Periodic Table [(7)4.A.1.c, e] . . . . . . . . . . . . . . . . . . . . . 216
Lesson 2 Compounds [(8)4.A.1.a, b, c] . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 222
Lesson 3 States of Matter [(6)4.C.1.c; (8)4.C.1.b] . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 227
Lesson 4 Physical Properties and Physical Changes [(8)4.B.1.a; (6)4.D.1.a, b] . . . . . . 233
Lesson 5 Chemical Properties and
Chemical Changes [(8)4.B.1.c; (8)4.D.2.b; (8)4.D.3.a] . . . . . . . . . . . . . . . . . . . . . . . . . . 238
The Science of Chemistry Review . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 244
UNIT 8 The Science of Physics . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 247
Lesson 1 Motion [(8)5.A.1.a, c] . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 248
Lesson 2 Force and Motion [(8)5.A.2.a, b, c] . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 254
Lesson 3 Energy Transformations [(8)5.A.4.a; (8)5.B.2.a, b; (6)5.C.2.b] . . . . . . . . . . . . . . 260
Lesson 4 Heat [(8)5.B.1.a, b] . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 265
Lesson 5 Electricity and Magnetism [(6)5.C.2.a; (6)5.C.3.b, c, d] . . . . . . . . . . . . . . . . . . 271
Lesson 6 Waves [(6)5.D.1.a, b, c] . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 278
The Science of Physics Review. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 282
UNIT 9 The Science of the Environment . . . . . . . . . . . . . . . . . . . . . . . . 285
Lesson 1 Natural Resources [(6)6.A.1.d, e; (6)6.B.1.c; (7)6.A.1.a; (6)5.C.2.a] . . . . . . . . . . . . 286
Lesson 2 Biodiversity [(6)6.A.1.c; (6)6.B.1.b; (7)6.B.1.a; (8)6.B.1.a, b]. . . . . . . . . . . . . . . . . . 291
Lesson 3 Global Warming [(6)6.A.1.d, e; (7)6.A.1.a; (7)6.B.1.a, b; (8)6.B.1.b] . . . . . . . . . . . . 298
Lesson 4 Chesapeake Bay [(6)6.A.1.c; (6)6.B.1.a, c; (7)6.B.1.a, b; (8)6.B.1.a] . . . . . . . . . . . . 302
The Science of the Environment Review. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 309
LESSON
LESSON
1
How Scientists
Do Science
2
Objectives 1.A.1.a, c, g; 1.B.1.a; 1.C.1.e
Scientists ask questions and make observations to learn about
the world. However, not all scientists do the same kind of work or
study the same things. In most cases, scientists who study different
things work together to understand complicated events or processes.
Let’s look at an example of how scientists do their work to learn
what scientists have in common and what they do differently.
Scientists Working Together: Climate Change
Many different things, such as the gases in the atmosphere and
the heat in the oceans, can affect Earth’s climate. Today, scientists
are studying Earth’s climate to learn how it changed in the past,
how it is changing now, and how it may change in the future.
Many different kinds of scientists work together to understand
the different things that can affect Earth’s climate. Meteorologists
(who study weather), oceanographers (who study the oceans),
geologists (who study Earth’s surface), chemists (who study how
matter changes), biologists (who study living things), and many
other kinds of scientists are involved in studying climate change.
These scientists do not all do their work in the same way. Some
do experiments in laboratories. Some carry out experiments in
natural settings, such as forests and oceans. Some make careful
observations of natural objects, events, or processes.
Which of these statements is true for all scientists?
The suffix -ology means
“the study of.” The prefix
geo- means “Earth.” The
prefix bio- means “life.”
So, a geologist is
someone who studies
Earth. A biologist is
someone who studies
living things.
Pay close attention to
words like all, best, and
always in test questions.
They can often help you
tell whether an answer is
correct.
A They all do experiments.
B They all study living things.
C They all make observations.
D They all work in laboratories.
To answer this question, think about whether each choice
describes something that all scientists do. Not all scientists do
experiments, study living things, or work in laboratories. So,
choices A, B, and D must be wrong. However, all scientists make
observations, whether or not they are participating in what is
happening. Choice C is correct.
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UNIT 1
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The Practice of Science
Scientific Investigations
Whether they do experiments, make models, or study natural
processes by making observations, all scientists follow some similar
steps in their investigations. These steps include:
•
•
•
•
•
•
•
•
asking questions and making predictions
learning what others know
planning investigations
making observations or collecting data
using models
analyzing observations or data
drawing conclusions
describing work to others
Remember that data are
pieces of information.
Data can be descriptions,
measurements, or other
observations.
Although all scientists use these steps, they do not all use them
in the same order. For example, a scientist usually needs to learn
what others know about a topic before she knows what questions
to ask. Let’s look at how a scientist studying climate change might
use these steps.
First, the scientist would ask a question. For example, she might
ask, “How could ice melting at the poles affect Earth’s air
temperatures?” The scientist would read about other scientists’
research to learn more about how ice at the poles affects Earth’s
climate. Then, she would form a hypothesis, or a possible answer
or explanation to her question. It is important that a hypothesis be
testable, so the scientist can find out if it can be proven. For
example, her hypothesis might be, “Ice melting at the poles causes
Earth’s climate to get cooler.”
A hypothesis is a
possible answer or
explanation to a
scientific question.
Next, the scientist would have to plan an investigation. There is
no way for her to do an experiment that will directly test the
hypothesis. However, she could make observations of natural
objects and processes. From reading other scientists’ work, she
would know that the ice at Earth’s poles has melted and re-formed
several times in the past. So, the scientist might study rocks, ice,
and fossils from millions of years ago, when there was less ice at
Earth’s poles. From her research, she could learn what Earth’s
climate was like back then.
Models in Science
The scientist may also use models during her investigation. A
model is an idea or object that represents something else. Scientists
may use models to study things that are too large, too small, too
complicated, or too far away to study directly. For example, a food
web drawn on a piece of paper is a model for the interactions of
certain organisms in real life.
UNIT 1
The Practice of Science
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A model is an idea or
object that represents a
different object, event,
or process.
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There are many different kinds of models. Two common kinds
that scientists use are physical models and mathematical models.
Globes and maps are examples of physical models. Physical
models are actual objects that represent other objects.
Remember that many
different models can
represent the same
thing. Which model you
use to represent
something depends on
what you need to learn.
Globes and maps are examples of physical models.
They are models of Earth.
Mathematical models use equations, numbers, or graphs to
represent objects, events, or processes. Many scientists who study
climate change use mathematical models. For example, they may
collect data on the temperature in an area over many years. Then,
they may use computers to find equations that can predict the
temperature in the future.
Scientists may use different models to represent the same thing.
For example, a scientist studying how water flows in the ocean may
use a mathematical model to make a graph of how ocean
temperatures change. The scientist may also use a map of the ocean
or a container of water to represent the ocean. Scientists decide
which kind of model to use based on what they want to learn.
A scientist wants to show the range of bald eagles in the
Chesapeake Bay area. Which would be most useful: a globe
or a map? In your answer, be sure to
• name the more useful tool
• explain why that tool is most useful
To answer this question, think about how maps and globes are
different. One important difference is that on maps, you can show
distances in kilometers and miles, which globes do not show.
Maps also show smaller areas in more detail than on a globe. The
Chesapeake Bay is too small to show up well on a globe. So in
this case, a map would be more useful than a globe.
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UNIT 1
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The Practice of Science
Analyzing and Sharing Data
Once the scientist has made observations and collected data,
she can analyze the information to learn what it means. She can
use them to infer, or guess, what happened to Earth’s climate in
the past when ice at the poles melted.
Even if the scientist’s results do not support her hypothesis, the
hypothesis and results can still be useful. They can help the
scientist decide which questions to ask next. They can also help
other scientists decide how to do their research. In other words, all
hypotheses are valuable, even if they turn out not to be provable.
To infer is to make an
educated guess based on
information.
Sharing Work with Others
No matter what the scientist’s results are, she should share them
with other scientists. Then, other scientists can learn what she did.
They can check her work to see if any errors were made or if she
forgot to include information. They can also use her results to help
them decide what they should study.
Scientists also share their results so that other scientists can
repeat their investigations. Scientists repeat investigations so they
can be sure the results are correct.
Which of these is least likely to be part of a scientific
investigation?
A asking a question
B making observations
C copying the data of others
D sharing your results with others
Asking questions, making observations, and sharing your work
with others can all be part of a science investigation. However,
you should never copy someone else’s data, so choice C is the
correct answer.
Hypotheses and Theories
Scientists do investigations to learn about the world around
them. They also look for explanations for their observations.
Scientists use hypotheses and theories to explain their observations.
Remember that a hypothesis is a possible answer or
explanation to a scientific question. In the climate-change
UNIT 1
The Practice of Science
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A theory is a general
explanation for all
available observations
and data.
11
example, the scientist’s hypothesis was that melting ice near the
poles would cause Earth to cool. Hypotheses can also be possible
explanations for how things work or how they are related.
If many observations and data support a hypothesis, the
hypothesis may become a scientific theory. In everyday language,
we often use “theory” to mean “guess.” However, in science, a
theory is an explanation that is supported by all the observations
and data scientists have. So, a scientific theory is much more than
a guess.
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UNIT 1
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The Practice of Science
It’s Your Turn
Please read each question carefully. To answer multiple-choice questions, circle the correct
response. To answer constructed response questions, write your answer in the space provided.
1 Which of the following questions is most likely to be answered
by a scientist?
A
What kind of stone looks nicest in a building?
B
Which kinds of animals act the strangest?
C
What keeps water hot longer, a metal cup or a glass cup?
D
Which look better, wooden chairs or plastic chairs?
2 Omar formed a hypothesis that mushrooms grow better in
bright light than in dim light. After he did his experiment, he
found out his hypothesis was incorrect. Then, he changed his
hypothesis to say that mushrooms grow better in dim light. His
new results supported his new hypothesis. Which of these
statements describes Omar’s original hypothesis?
A
It was useful only because it was true.
B
It did not have to be testable because it was false.
C
It was useful even though it was false.
D
It supported the results of Omar’s original investigation.
3 Which of the following best explains why it is important for
scientists to repeat their investigations?
A
so other scientists can copy their data
B
to make sure the results are correct
C
so they do not have to think of new questions
D
to make sure no one else does the same investigation
4 What is the main reason why scientists have different ways of
conducting investigations?
A
Some ways are more fun than others.
B
They don’t know how to do real science.
C
They are trying to answer different questions.
D
They want their results to always be different.
UNIT 1
The Practice of Science
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13
5 Mari wants to use a model to help her learn the sizes and
shapes of the bones in her body. She can look at a drawing of
a skeleton or examine a plastic skeleton. Which would be more
useful? In your answer, be sure to
• identify which model would be more useful for Mari
• give a reason why that model would be most useful
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UNIT 1
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The Practice of Science