Holt Science and Technology Grade 8 Tennessee Comprehensive ...

Holt Science and Technology 

Grade 8 

Tennessee Comprehensive 

Assessment Program 

Test Preparation Workbook

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ISBN 13: 978-0-55-401786-0 

ISBN 10: 0-55-401786-5 

1 2 3 4 082 11 10 09 08

Contents 

Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .iv 

Characteristics of Science Standards 

Tennessee Inquiry Standard 

GLE 0807.Inq.1 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1 

GLE 0807.Inq.2 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3 

GLE 0807.Inq.3 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5 

GLE 0807.Inq.4 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7 

GLE 0807.Inq.5 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9 

Tennessee Technology & Engineering Standard 

GLE 0807.T/E.1 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 11 

GLE 0807.T/E.2 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 13 

GLE 0807.T/E.3 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 15 

GLE 0807.T/E.4 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 17 

Content Standards 

Tennessee Standard 5: Biodiversity and Change 

GLE 0807.5.1 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 19 

GLE 0807.5.2 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 21 

GLE 0807.5.3 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 23 

GLE 0807.5.4 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 25 

GLE 0807.5.5 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 27 

GLE 0807.5.6 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 29 

Tennessee Standard 9: Matter 

GLE 0807.9.1 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 31 

GLE 0807.9.2 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 33 

GLE 0807.9.3 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 35 

GLE 0807.9.4 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 37 

GLE 0807.9.5 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 39 

GLE 0807.9.6 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 41 

GLE 0807.9.7 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 43 

GLE 0807.9.8 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 45 

GLE 0807.9.9 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 47 

Tennessee Standard 12: Forces in Nature 

GLE 0807.12.1. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 49 

GLE 0807.12.2. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 51 

GLE 0807.12.3. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 53 

GLE 0807.12.4. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 55 

GLE 0807.12.5. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 57 

TCAP Practice Test A . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 59 

TCAP Practice Test B . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 97 

Copyright © by Holt McDougal. All rights reserved. 

Holt Science and Technology, Georgia 

Performance Standard Review Guide

Introduction 

This workbook consists of practice activities designed to prepare your students to take 

the Tennessee Comprehensive Assessment Program Test. The questions are correlated to the 

Tennessee Science Standards as well as the appropriate Skills and Processes Standards. This 

breadth of content coverage provides teachers with an opportunity to assess their students’ 

understanding of the essential science knowledge and skills at the middle school level. These 

assessments can then help identify topics or concepts in need of re-teaching or additional 

practice and should be used to inform curricular decisions on the classroom or school levels. 

Copyright © by Holt McDougal. All rights reserved. 

Holt Science and Technology, Georgia 

Performance Standard Review Guide

Grade 8 – Inquiry 

GLE 0807.Inq.1 Design and conduct open-ended scientific investigations. 

STANDARD REVIEW 

Designing a good experiment requires planning. Every factor should be considered. 

For example, a possible hypothesis about deformities in frogs is that they were 

exposed to an increased amount of ultraviolet (UV) light as eggs. If an increase in 

exposure to ultraviolet light is causing the deformities, then some frog eggs exposed to 

increasing amounts of ultraviolet light in a laboratory will develop into deformed frogs. 

An experiment to test this hypothesis is summarized in Table 1. In this case, the 

variable is the length of time the eggs are exposed to UV light. All other factors, 

such as the temperature of the water, are the same in the control group and in the 

experimental groups. 

In a well-designed experiment, the differences between control and experimental 

groups are caused by the variable and not by differences between individuals. The 

larger the groups are, the smaller the effect of a difference between individual frogs 

will be. The larger the groups are, the more likely it is that the variable is responsible 

for any changes and the more accurate the data collected are likely to be. Scientists 

test a result by repeating the experiment. If an experiment gives the same results 

each time, scientists are more certain about the variable’s effect on the outcome. 

Table 1 Experiment to Test Effect of UV Light on Frogs 

Group 

Kind of frog 

Control Factors 

Number of eggs Temperature 

Variable 

UV light exposure 

1 (Control) Leopard frog 100 25°C 0 days 

2 (Experimental) Leopard frog 100 25°C 15 days 

3 (Experimental) Leopard frog 100 25°C 24 days 

GUIDED PRACTICE 

Directions: Using the Standard Review and what you have studied, read each 

question and circle the letter of the best response. 

Which term below best describes a hypothesis? 

A the result of an experiment 

B a well-tested explanation for why something happens 

C a random guess about what causes something 

D a possible explanation of an observation or result 

The correct answer is D. A hypothesis is a possible explanation based on 

observations or reason, so it is not a random guess (Answer C). It is the basis for 

an experiment, not a result (Answer A). A well-tested explanation (Answer B) is a 

theory, not a hypothesis. 

Copyright © Holt McDougal. All rights reserved. 

1 

Holt Science and Technology, 

TCAP Test Preparation Workbook


STANDARD PRACTICE 

1. You are given a sample of a solid material and want to determine 

whether it is an element or a compound. How could you design an 

experiment that you could use to determine whether the sample is an 

element? 

A Add the material to water and check the pH to see if it is acidic. 

B Measure a number of physical and chemical properties and compare 

them to reported properties of elements. 

C Read everything that you can find about elements to see if your sample is 

described anywhere. 

D Assume that it is a compound because there are many compounds, but 

only a few elements. 

2. Which of the following is not an example of a hypothesis that can be 

tested with an experiment? 

F Nonliving things do not grow and develop. 

G Lipids do not mix with water. 

H Plant cells contain DNA. 

J Dogs are better than cats. 

3. What helps focus an investigation? 

A taking a test 

B answering a question 

C asking a question 

D working with lab equipment 

4. a. You need to characterize a solution in a science lab experiment. 

When you add baking soda to the substance it bubbles and foams. 

What hypothesis can you make about the solution? 

b. How could you test your hypothesis? 


2 




GLE 0807.Inq.2 Use appropriate tools and techniques to gather, organize, 

analyze, and interpret data. 


In most experiments, you will measure some quantity, such as distance, mass, 

temperature, or time. When you work in the lab, you will use scientific apparatus to 

make these measurements and control experiments. It is important that you follow 

the correct procedures for using the apparatus. Techniques for using equipment will 

be provided by your teacher or in instructions in your lab book. It is important to 

read and follow all procedures exactly. If you use equipment incorrectly, you may 

create a safety hazard or get incorrect results. It is important to follow instruction in 

the correct sequence and observe all safety guidelines. 

After you finish collecting data, you will use tables, graphs, diagrams, maps, or other 

visual displays, to analyze and interpret it. These tools point out the relationships 

in the numbers that record your measurements. Part of conducting a successful 

experiment is analyzing your data to find any hidden patterns. Two common 

patterns that you might see on a graph of experimental data are linear relationships, 

in which data tend to form a straight line, and repeating relationships, in which a 

cycle of changing values shows up in the analysis. When you analyze data you also 

need to look at methods of measurement and calculation to find the difference 

between a predicted amount and a calculated amount. 




What should you do if you are not sure how to use a piece of laboratory 

equipment? 

A Stop working on the experiment. 

B Ask another student to show you how to use the equipment. 

C Check the lab instructions for the correct techniques. 

D Make your best guess about how it works. 

The correct answer is C. When you run an experiment that uses equipment, you can 

get information on using it from the lab instructions or from your teacher. You should 

find out how to use the equipment and then continue the experiment (Answer A). You 

should never guess if you don’t know how to use the equipment (Answer D) or ask 

someone other than your teacher (Answer B) because you might introduce an error 

that could cause a safety hazard or change the results of the experiment. 


3 





1. An experiment calls for water as one of the items to test. Absent any 

other instructions, which kind of water should you use? 

A distilled water 

B bottled water 

C tap water 

D rain water 

2. When using a graduated cylinder to measure volume, which is not 

necessary to get an accurate reading? 

F Place the cylinder on a flat, level surface before measuring liquid. 

G Move your head so that your eye is level with the surface of the liquid. 

H Shake the contents to prevent a bond from forming with the cylinder. 

J Read the mark closest to the liquid level. 

3. The most common cause of accidents in scientific experiments is 

A failing to follow instructions. 

B using improper safety equipment. 

C failing to recognize safety symbols. 

D failing to have a neat work area. 

4. a. In an experiment, you need to find the density of a piece of metal that 

has an irregular shape. How could you determine its density? 

b. Why would you use SI units for the measurements in the experiment 

above? 


4 




GLE 0807.Inq.3 Synthesize information to determine cause and effect 

relationships between evidence and explanations. 


Once scientists finish their tests, they must analyze the results. Scientists often make 

graphs and tables to organize and summarize their data. Analysis also includes 

comparing new data with known information to discover what new information 

the new data provide. After carefully analyzing the results of their tests, scientists 

must decide whether their results supported the hypothesis. The conclusion is 

an interpretation of the results and how they compare to the original ideas of the 

hypothesis. If a scientist concludes that the results support the original hypothesis, 

the conclusion may suggest new questions for further study. 

One way to test a hypothesis is to do a controlled experiment. A controlled experiment 

compares the results from a control group with the results from one or more 

experimental groups. The control group and the experimental groups are the same 

except for one factor. This factor is called a variable. The experiment will then show 

the effect of the variable. If your experiment has more than one variable, determining 

which variable is responsible for the experiment’s results will be difficult or impossible. 




In an experiment, a closed container is heated and the pressure inside the 

container is measured. Which of these conclusions can you make based on 

the data below? 

Pressure measured in a closed container 

Volume Temperature Gas in Container Pressure 

100 mL 0ºC nitrogen 100 kPa 



A Increasing the volume causes an increase in pressure. 

B Increasing the temperature of nitrogen in a closed container causes the 

pressure to increase. 

C Increasing the temperature of any material causes its pressure to increase. 

D Increasing the pressure in a closed container causes the temperature 

to increase. 

The correct answer is B. Answer D is incorrect because the experiment changed the 

temperature and observed the pressure. Answer A is incorrect because the volume 

was constant. Because only nitrogen was studied, you cannot make conclusions 

about other materials (Answer C). 


5 





1. Which of the following accurately describes what scientists mean by a 

controlled experiment? 

A The outcome is controlled. 

B One variable remains fixed while other variables are changed. 

C One variable changes throughout the experiment while all other variables 

remained fixed. 

D Experimental results are obtained by computer models. 

2. Enrique is conducting an experiment to study the effects of music on 

plant growth. The table below shows the experimental setup Enrique is 

planning. There is no control group included in the table. What group 

would make a good control for Enrique’s experiment? 

Plant Number Type of Music Plant Growth 

Observation 

1 Classical 

2 Classical 

3 Rock 

4 Rock 

A plants that have not been exposed to any music 

B plants that have been exposed to both kinds of music 

C plants that have been exposed to a third kind of music 

D plants that have been exposed to only one kind of music 

3. A research group is presenting data on an analysis of elements that 

make up the human body. 

a. What types of graph would best compare the percentages of elements 

in the body in a way that is easy to interpret? 

b. What type of graph would best compare changes in the oxygen 

content of the body over the course of a day? 


6 




GLE 0807.Inq.4 Recognize possible sources of bias and error, alternative 

explanations, and questions for further exploration. 


Established theories are usually built on many experiments and observations. When 

new experimental results do not agree with the existing theory, scientists generally 

do not revise the theory immediately. Sometimes the results of the experiment 

contain an error in the data or the analysis. Even after an experiment has been 

reproduced independently, more information may be needed. Different scientists 

may interpret the results in different ways. In that case, further experiments are 

needed. The original experiment might suggest new ways to test the hypothesis. 

Scientific investigations are a continual process. When the results of an experiment 

are reported, they are reviewed and compared to existing theories. Even after 

results are reviewed and accepted by the scientific community for publication, the 

investigation of the topic may not be finished. New evidence may become available. 

The scientist may change the hypothesis based on the new evidence. In other cases, 

the scientist may have more questions that arise from the original evidence. When 

a number of different experiments all provide data that are not consistent with the 

theory, the theory is usually revised. 

An example of a hypothesis that was not immediately accepted was Alfred 

Wegener’s hypothesis of continental drift. Wegener analyzed fossils on several 

continents, and he found that some continents had fossils similar to fossils on 

other continents. After making many observations, Wegener proposed that the 

continents were once a supercontinent but later drifted apart. Although his results 

were confirmed by other scientists, Wegener’s hypothesis was not generally 

accepted right away. Many scientists did not accept his hypothesis because it 

did not seem possible for the crust to move in the way he proposed. Until further 

investigations showed how the continents could move, continental drift was not 

generally accepted. Wegener’s observations are now part of the support for the 

theory of plate tectonics, which describes the movement of the continents. 




A report of which of the following observations would be inconsistent with 

current theories about Earth? 

A Satellite data that shows continents moving. 

B Measurements show Earth’s core is made of molten rock. 

C Earth’s revolution around the sun takes slightly more than 365 days. 

D Observations show air pressure is lowest at sea level. 

The correct answer is D. There is no current theory that would explain air pressure 

being lowest at sea level. The other observations are all consistent with our current 

understanding of how the planet functions. 


7 





1. Which of Dalton’s statements about the atom was proven false by J. J. 

Thomson? 

A Atoms cannot be subdivided. 

B Atoms are tiny. 

C Atoms of different elements are not identical. 

D Atoms join to form molecules. 

2. Of two experiments designed to study global warming, experiment A 

focuses on readings from instruments all over the world that measure 

sea levels, while experiment B focuses on a particular region of ice in 

Antarctica. Which is the better experiment? 

F experiment A 

G experiment B 

H both have merit 

J neither has merit 

3. Nate notices that water droplets are starting to form on the outside of a 

glass beaker filled with cold water. Nate thinks that the beaker may be 

leaking. What other conclusion might Nate draw? 

A Water is evaporating from the beaker. 

B Water is condensing on the sides of the beaker. 

C Water is freezing in the beaker. 

D Water is dissolving the beaker. 

4. a. When talking about designing or reporting an investigation, what 

does bias mean? 

b. Why do scientists try to avoid bias in their experiments? 


8 




GLE 0807.Inq.5 Communicate scientific understanding using descriptions, 

explanations, and models. 


A key part of scientific research is communicating the results of an experiment. 

Scientific writing must present detailed information in a way that is very specific. 

That means it is very different from the literary writing that you use to tell a story 

or support a political point of view. Whether you are writing a laboratory report for 

your teacher or submitting a paper to a scientific journal, your lab report should 

contain enough information so that others can use it to reproduce your experiment 

and compare their results to yours. 

A pattern, plan, representation, or description designed to show the structure or 

workings of an object, system, or concept is a model. With a model, a scientist can 

explain or analyze an object, system, or concept in more detail. Models are used in 

science to help explain how something works or to describe how something is structured. 

After scientists have collected their data, they organize it into tables, charts, or 

graphs in order to look for trends and identify relationships among the variables. 

These visuals can show new information. For example, all of the data in a single row 

or column in a table have at least one characteristic in common. That characteristic 

is labeled in the row or column’s label. In the table below, all of the values in the first 

column are temperatures given in degrees Celsius. 

Temperature (°C) Time to double bacteria population (min) 

10 130 

20 60 

30 29 

40 19 

50 no growth 




How does scientific writing differ from literary writing? 

A The two types of writing have different purposes. 

B Scientific reports are always written in English. 

C Science writing is shorter than literary writing. 

D Science writing is about facts, and literary writing is fiction. 

The correct answer is A. Science writing must present details in a clear and detailed 

way, unlike literary writing. Scientific reports can be written in any language (Answer 

B), and they can be long or short, depending on the amount of information to be 

presented (Answer C). Nonfiction literary writing is also about facts (Answer D). 


9 





1. Organizing data into a graph is an example of 

A collecting data. 

B forming a hypothesis. 

C asking a question. 

D analyzing data. 

2. Which of the following statements best describes the relationship 

between the water pressure on an object and the depth of the object in 

the ocean? 

Pressure (MPa) 

Water Pressure Versus Depth 

2.5 

2.0 

1.5 

1.0 

0.5 

0 

0 50 100 150 

Depth (m) 

F Water pressure increases as the depth increases. 

G Water pressure decreases as the depth increases. 

H Water pressure does not change as the depth increases. 

J Water pressure has no predictable relationship to the depth. 

3. During a laboratory investigation, scientists graphed the decay rate of 

the radioactive isotope carbon-14. 

Amount of C-14 (g) 

10 

9 

8 

7 

6 

5 

4 

3 

2 

1 

0 

200 

Radioactive Dating Using Carbon-14 

250 

11,460 17,190 22,920 28,650 34,380 

Time (years) 

a. According to the graph above, what is the approximate age of the 

sample when it contains 3/10 of the original 10 g of carbon-14? 

b. Why is carbon-14 dating not useful for objects older than about 

30,000 years? 


10 



Grade 8 – Technology and Engineering 

GLE 0807.T/E.1 Explore how technology responds to social, political, and 

economic needs. 


Scientists study the natural world. Engineers work to put scientific knowledge to 

practical use and to build the tools to use scientific knowledge. Some engineers 

design and build the buildings, roads, and bridges that make up cities. Others design 

and build electronic things, such as computers and televisions. Some even design 

processes and equipment to make chemicals and medicines. Engineers may work 

for universities, governments, and private companies. 

While the driving force behind science is curiosity, the driving force behind technology 

is finding a solution to a social, political, or economic need. Technologies that societies 

need include power, communication, medical care, and transportation. Science and 

engineering together address these needs as they continually change. The internet, 

for example, combines many technologies to link distant parts of the world together 

in ways that were impossible even a few decades ago. Each communication advance 

leading to the internet combined scientific knowledge and engineering application. 

Political needs in a society include infrastructure used by everyone, such as roads 

and bridges. Another political need is defense, leading to the development of military 

technologies. Economic needs drive many technologies, including the development of 

better systems of manufacturing and distribution of materials. 

Technology is a very broad term that includes many different types of application 

of science. It can be an object or device, such as a medical imaging machine. It 

can be a technique or method, such as a new way to make a fuel from grain crops. 

Technology can also be a system of production, for example, the assembly line, 

which changed how products were made throughout the world. 




Which of the following is an example of technology? 

A a pair of pliers 

B a way to breed a new plant with desirable characteristics 

C manufacturing robots that assemble automobiles 

D all of the above 

The correct answer is D. All of these are examples of different types of technology. A pair 

of pliers (Answer A) is not a newly discovered technology, but it is the application of 

scientific principles to make a tool. The technique describe in Answer B is an example of 

a new method of doing something based on science. Robotic manufacturing (Answer C) 

is a technological system that has changed many manufacturing industries. 


11 





1. Which of the following was research that had to be studied before 

alternative fuels for automobile engines could be developed? 

A how light interacts with glass 

B how chemical substances combine with air 

C the number of people who drive into and out of a city each day 

D how to make engines quieter 

2. Which type of technology is primarily developed by scientists and 

engineers who study the interactions of atoms in chemical compounds? 

F synthetic fibers and fabrics 

G computer hard drives 

H transmission of electrical energy 

J custom speakers for a large auditorium 

3. Which type of technology would most likely be based on an 

understanding of the Periodic Table? 

A strong but lightweight metals 

B improved computer memory 

C faster internet connections 

D using microbes to manufacture drugs 

4. a. How does technological research into the development of new fabrics 

benefit society? 

b. How can you tell if a new technology has provided a benefit? 


12 




GLE 0807.T/E.2 Know that the engineering design process involves an 

ongoing series of events that incorporate design constraints, model building, 

testing, evaluating, modifying, and retesting. 


Technology is the process by which humans modify nature to meet their needs. 

Technology includes the products, equipment, and systems that you use every day, 

but it is more than that. Technology also includes the processes used to develop and 

build those products. 

A major part of developing new technologies is engineering design. Engineering 

consists of the knowledge of the design to make products and develop processes 

to solve problems. As with scientists, the work of engineers must follow the laws of 

nature. Engineers also have to consider what materials are available, what safety 

problems may exist, and what the effects are on the environment. 

In order to achieve their goals and develop new technologies, engineers use a 

design process. This process has many steps but it can be summarized as follows: 

• identify the problem to be solved 

• conduct research 

• make decisions about materials and processes 

• design and build models 

• perform tests and evaluate the results 

• modify the product or system 

• test again and repeat the design process as many times as necessary 

• build the technology 

During this process, engineers may try many different materials and arrangements. 

When the change makes the product better, less expensive, more reliable or 

improved in any other way, it may be included in the next test. New scientific 

discoveries can become part of new design, making designs work even better. 




As part of an engineering design process, engineers want to make a less 

expensive disposable towel. Which of these materials would they most likely 

want to test? 

A silk B iron 

C paper D fiberglass 

The correct answer is C. Of the choices, paper is both the least expensive and most 

likely to work as a towel. Silk (Answer A) is a fabric that could be used, but it is much 

too expensive for a disposable product. Iron and fiberglass (Answers B and D) can 

both be woven into a flexible, cloth-like material but it would not be likely to work 

as a towel. Both materials would also be too expensive for a disposable towel even if 

they could work for the purpose. 


13 





1. Which of the following would be most important in designing a 

treatment to keep wood from rotting in playground equipment? 

A availability of materials for manufacturing it 

B the method for applying it to the wood 

C not toxic to people 

D can be produced at a low cost 

2. An engineering team is designing a new type of transformer to 

use in the power grid. Which of these would not be an important 

design problem? 

F The transformer is not compatible with most existing transformer 

stations. 

G The transformer housing is not waterproof. 

H Power must be turned off frequently for maintenance. 

J The best conductor for the transformer is copper wire. 

3. a. Why do engineers, who design new computer chips, start with models 

that are thousands of times larger than the actual device? 

b. Why might the computer chip prototype team include a visual artist 

or graphic designer? 


14 




GLE 0807.T/E.3 Compare the intended benefits with the unintended 

consequences of a new technology. 


The purpose of technology is to use science and engineering to solve problems 

and provide products and processes that people need. Technology has provided all 

the systems that hold our society together, including electric power, transportation 

networks, medical care, food supplies, and many others. Unfortunately, technology 

systems do not always work exactly as they are planned. Sometimes systems break 

down and stop working. Often, in addition to the planned benefits of technology, 

there are undesirable effects. These unintended consequences are problem caused by 

technology, which were not expected. 

An example of an unintended consequence of technology is air pollution caused 

by burning fossil fuels. Transportation technology has certainly served its purpose. 

Automobiles, trucks, and airplanes provide the intended benefit, allowing people 

and goods to move easily from one place to another. At the same time, there have 

been unintended consequences of this technology. Acid rain caused by impurities 

in gasoline has damaged structures and destroyed stream ecosystems. Carbon 

dioxide released into the atmosphere when fuels burn is expected to cause dramatic 

changes in the world’s climates. Another unintended consequence of transportation 

technology based on oil is political tension, which is the result of the uneven 

distribution of oil resources among different countries. 




Which of these is an unintended consequence of technology? 

A communicating with people in other countries by instant messages 

B using your computer to find information about an illness from a library 

far from you home 

C people finding your personal information by using their computers 

D being able to purchase a CD online that is not available in a local store 

The correct answer is C. One of the unintended consequences of the internet is that 

people can sometimes find information online that should not be public. The other 

choices are all intended benefits of internet technology: the ability to communicate 

easily (Answer A), find information quickly (Answer B) and shop at stores in other 

cities (Answer D). 


15 





1. What could be an unintended consequence of a train that uses powerful 

magnets to lift it above the track and propel it forward? 

A faster travel between cities 

B magnetic interference with communication devices 

C less friction between the train and the track 

D reduced consumption of fossil fuels 

2. Which of the following is an example of an intended benefit of a new 

technology? 

F New alloys reduce the amount of fuel used by jet airliners. 

G Cheaper paper in books causes them to disintegrate after a few years. 

H Large wind turbines interrupt bird migration pathways. 

J A more energy efficient car has a battery that must be replaced often. 

3. Which of these effects is an unintended consequence of technology? 

A Air traffic control improvements reduce flight delays. 

B A groundcover plant to stabilize hillsides becomes an invasive species. 

C A new fabric does not develop wrinkles in your suitcase. 

D New structural system allow buildings to be built taller. 

4. a. What are some of the intended benefits of a dam built to produce 

hydroelectric power? 

b. What are some possible unintended consequences of a dam built to 

produce hydroelectric power? 


16 




GLE 0807.T/E.4 Describe and explain adaptive and assistive bioengineered 

products. 


Many technologies are based on new discoveries about life and how organisms change 

and adapt to their environments. Bioengineering applies the ideas of engineering to the 

science of living things. Chemical processes inside living cells control life and death, 

growth, reproduction, and how the cell interacts with its environment. 

Scientists and engineers study the chemical reactions inside cells and learn how 

cells adapt to their environment. They also look at the structure of tissues and 

organs in plants and animals. 

By using what they learn about living things, bioengineers develop new, useful products. 

Many of these products are used for health care. They use the knowledge of how cells 

operate to design new drugs that work better. Materials that can be implanted inside the 

human body are used to make artificial joints. Other new materials can replace body 

tissues, such as heart valves that are damaged by a viral infection. New bioengineered 

systems have allowed blind people to see and deaf people to hear by connecting devices 

directly to the body’s nervous system. Bioengineers have also developed artificial arms 

and legs that can be controlled, through the nervous system, by a person’s brain. 

Bioengineers also work in other fields. In agriculture, for example, they modify the 

genes inside the cells of plants so that the plants kill harmful insects that eat their 

leaves. Other plants have been modified to produce bigger crop yields or to increase 

the amount of oil in their tissues, which can be extracted for use in fuel. These fuel 

oils from bioengineered plants are called biofuels. 

In some cases, bioengineers can actually develop organisms to produce a material 

that is useful or performs a desirable function. Insulin, a medicine for treating 

diabetes, can be manufactured by bioengineered bacteria and then purified for 

medicinal use. Some bioengineered bacteria eat chemicals that are spilled in the 

environment. These bacteria have been modified so that they survive by eating oil 

or other chemicals absorbed by the ground or floating in water. 




Which of these is the best example of a product developed by bioengineers? 

A the internet B cars that use less fuel 

C bacteria that produce silk D a new metal alloy 

The correct answer is C. Although it is possible that bioengineering could have been 

used in the other products, the design of a new living cell is the best example of 

bioengineering because it modifies a living cell. The internet (Answer A) is based on 

electronics and system engineering, fuel-efficient cars (Answer B) are generally developed 

by mechanical engineering, and metal alloys are developed by chemical engineering. 


17 





1. Which of these is an example of how bioengineering could be used to 

save a species of animal that is being killed by a new disease? 

A keeping animals in zoos so that they do not have contact with diseased 

animals 

B hunting animals that are sick to remove them from the population 

C modifying genes of some animals to improve their ability to recover 

D clearing a forest so the diseased animals get more sunlight 

2. Which of the following is not a reason that bioengineering might be 

used to modify the genes of dairy cows? 

F to increase the amount of milk produced 

G to lower the production cost of milk 

H to develop cattle that are able to survive in areas beyond their normal 

environment 

J to make the cows less resistant to infections 

3. a. Extremophiles are microorganisms that live in conditions, such as 

very hot or cold temperatures or high acidity, that would destroy 

most organisms. Why would extremophiles be interesting to 

bioengineers? 

b. How could bacteria that eat crude oil be useful? 


18 



Grade 8 – Life Science: 

Standard 5 – Biodiversity and Change 

GLE 0807.5.1 Identify various criteria used to classify organisms into groups. 


For hundreds of years, all living things were classified as either plants or animals. 

However, over time, scientists discovered species that did not fit easily into these two 

kingdoms. Today, life is classified into three domains: Archaea, Bacteria, and Eukarya. 

Most living things are prokaryotes, single-celled organisms that do not have a 

nucleus. Two domains, Archaea and Bacteria, consist of prokaryotes. 

We are generally more familiar with members of the domain Eukarya. Eukaryotes 

are all organisms that have a nucleus and membrane-bound organelles. The 

domain is divided into four kingdoms: Protista, Fungi, Plantae, and Animalia. 

Protists are single-celled or simple multicellular organisms, including protozoans, 

algae, and slime molds. Fungi are complex, multicellular organisms that absorb 

nutrients from substances in their surroundings. Fungi include molds and mushrooms. 

Plants include organisms that are eukaryotic, have cell walls, and make food through 

photosynthesis. Animals are complex, multicellular organisms that do not have cell 

walls, are usually able to move around, and have specialized sense organs. 

All living things in a kingdom are further sorted into phyla. The members of a phylum 

are sorted into classes. Each class includes one or more orders. Orders are separated into 

families. Families are broken into genera, and genera are sorted into species. A species is 

a group of organisms that are closely related and can mate to produce fertile offspring. 

Scientists also use shared characteristics to hypothesize how closely related living 

things are. The more characteristics the organisms share, the more closely related 

the organisms may be. For example, the platypus, brown bear, lion, and house 

cat are thought to be related because they share many characteristics. They are 

all classified as mammals. Recently the ability to characterize the genes in DNA 

have made it possible to analyze relationships among groups of living things using 

information beyond observable characteristics. 


Directions: Using the Standard Review and what you have studied, read 

each question and circle the letter of the best response. 

Scientists classify organisms by 

A arranging the organisms in orderly groups. 

B giving the organisms many common names. 

C deciding whether the organisms are useful. 

D using only existing categories of classification. 

The correct answer is A. Organisms are classified in orderly groups depending on 

characteristics that are similar. Common names (Answer B) generally do not reflect 

the true relationship between organisms. Usefulness is a meaningless term when you 

are discussing the science of organisms (Answer C). The categories that scientists use 

change as new data add to what is known about organisms (Answer D). 


19 






1. Animals can mate and produce fertile offspring, if they belong to the 

same 

A domain. 

B species. 

C phylum. 

D order. 

2. Which of the following characteristic would not be used to classify 

animals into a group? 

F whether the animals are mammals 

G the genders of the animals 

H whether the animals have feathers 

J the sounds that the animals can make 

3. Which of these consists of organisms that are prokaryotes? 

A Archaea 

B Animalia 

C Fungi 

D Protista 

4. The diagram below is a branching diagram. It shows the results of a 

laboratory experiment that defined some similarities and differences 

among five animals. 

a. Which two animals are the most closely related? Explain your answer. 

b. Which two animals are the most distantly related? Explain your answer. 


20 





GLE 0807.5.2 Use a simple classification key to identify a specific organism. 


A dichotomous key is an identification aid that uses sequential pairs of descriptive 

statements. From each pair of statements, the person trying to identify the organism 

chooses the statement that describes the organism. By working through the 

statements in the key in order, the person can eventually identify the organism. 

Dichotomous Key to 10 Common Mammals in the Eastern United States 

1. a. This mammal flies. Its “hand” forms a wing. 

b. This mammal does not fly. Its “hand” does not form a wing. 

2. a. This mammal has no hair on its tail. 

b. This mammal has hair on its tail. 

3. a. This mammal has a short, naked tail. 

b. This mammal has a long, naked tail. 

4. a. This mammal has a black mask across its face. 

b. This mammal does not have a black mask across its face. 

5. a. This mammal has a tail that is flat and paddle shaped. 

b. This mammal has a tail that is not flat or paddle shaped. 

6. a. This mammal is brown and has a white underbelly. 

b. This mammal is not brown and does not have a white 

underbelly. 

7. a. This mammal has a long, furry tail that is black on the tip. 

b. This mammal has a long tail that has little fur. 

8. a. This mammal is black and has a narrow white stripe on its 

forehead and broad white stripes on its back. 

b. This mammal is not black and does not have white stripes. 

9. a. This mammal has long ears and a short, cottony tail. 

b. This mammal has short ears and a medium-length tail. 

little brown bat 

Go to step 2. 

Go to step 3. 

Go to step 4. 

eastern mole 

Go to step 5. 

raccoon 

Go to step 6. 

beaver 

opossum 

Go to step 7. 

Go to step 8. 

longtail weasel 

white-footed mouse 

striped skunk 

Go to step 9. 

eastern cottontail 

woodchuck 




Based on the key above, what mammal has a long, cylindrical, hairless tail, 

and hand-like paws? 

A beaver B opossum 

C eastern mole D woodchuck 

The correct answer is B. The eastern mole (Answer C) is eliminated in box 3 because 

it has a short tail; the beaver (Answer A) is eliminated in box 5 because it has a flat 

tail; the woodchuck (Answer D) is eliminated in box 2 because it has hair on its tail. 


21 






1. According to the dichotomous key, what is a flightless mammal that has a 

long, furry tail with a black tip, a white underbelly, and light brown fur? 

A beaver 

B eastern mole 

C longtail weasel 

D opossum 

2. Students using the dichotomous key below notice that one tree has thin 

1.2 cm needles that occur in clusters. Which of the following inferences 

can be made? 

A Dichotomous Key to Common Trees of the Northern United States 

1. a. Leaves are thin and needlelike (coniferous) 

b. Leaves are broad and fanlike (deciduous) 

2. a. Needles are over 2.5 cm long and are clustered 

b. Needles are 1.25 cm long or less. 

3. a. Needles occur in clusters of 3 

b. Needles occur in clusters of 5 

F The plant is deciduous. 

G The plant is a Pinus rigida. 

H The plant is an Eastern white pine. 

Go to 2 

Go to 6 

Go to 3. 

Go to 4. 

Pitch pine (Pinus rigida) 

Eastern white pine (Pinus strobus) 

J The plant cannot be identified from the information provided. 

3. a. What is a dichotomous key? 

b. Describe how a dichotomous key helps identify organisms. 


22 





GLE 0807.5.3 Analyze how structural, behavioral, and physiological 

adaptations within a population enable it to survive in a given environment. 


Since life first appeared on Earth, many species have died out, and many new 

species have appeared. Scientists observe that species have changed over time. They 

also observe that the inherited characteristics in populations change over time. A 

characteristic that helps an organism survive and reproduce in its environment is 

called an adaptation. Adaptations may be physical, such as a long neck or striped fur. 

Adaptations might also be behaviors that help an organism find food, protect 

itself, or reproduce. A behavioral response is a set of actions determined partly by 

heredity and partly by experience. A behavioral response requires coordination 

and communication at many levels, from cells to organ systems to organisms. An 

individual organism’s behavior can also change as it adapts to its environment. How 

the organism is able to react determines how likely it is to survive and reproduce. 

Behavioral responses depend on how the organism must interact with its 

environment. To survive, predators must be able to catch their prey. The cheetah, 

for example, is able to run very quickly to catch its prey. Other predators, such as 

the goldenrod spider, ambush their prey. Prey animals have their own methods and 

abilities to keep from being eaten. Prey animals are able to run away, stay in groups, 

or camouflage themselves. Antelopes and buffaloes stay in herds. All the eyes, ears, 

and noses of the individuals in the group are watching, listening, and smelling for 

predators. This behavior increases the likelihood of spotting a potential predator. 

Another way animals avoid being eaten is by being hard to see. A rabbit often stays 

still so that its natural color blends into a background of shrubs or grass. Blending in 

with the background is called camouflage. Many animals mimic twigs, leaves, stones, 

bark, or other materials in their environment. 




Behaviors that prey use to avoid being eaten include 

A camouflage. B running quickly. 

C staying in a group. D all of the above. 

The correct answer is D. Any of these behaviors can help prey avoid capture by 

predators. If the prey is faster than the predator (Answer B), the chance of escape is 

good. Camouflage (Answer A) is a way to avoid being seen. Groups (Answer D) work 

together to detect or confuse predators. 


23 






1. A prairie dog runs into its burrow as a coyote approaches. This 

behavior helps the prairie dog 

A find a mate. 

B defend its food source. 

C avoid being eaten. 

D lure the coyote into danger. 

2. Which of the following is a behavior that helps a predator capture prey? 

F rationing food supply 

G defending a den from attackers 

H waiting in ambush 

J producing many young 

3. Which of these statements about behavioral response is true? 

A requires communication and coordination at many levels 

B does not change as a result of environment 

C is not passed down through generations 

D has no influence on an organism’s survival 

4. a. A predator repeatedly avoids prey that is red in color. Explain why 

the predator would exhibit this behavior. 

b. Describe another way in which prey might use coloring to avoid 

being eaten by a predator. 


24 





GLE 0807.5.4 Explain why variation within a population can enhance the 

chances for group survival. 


Genetic variation is important for the survival of a species. Populations with a low 

genetic variation are less likely than populations with a high genetic variation to 

adapt to changes in their environment. 

1 OVERPRODUCTION A tarantula’s egg sac may 2 

3 

Four Parts of Natural Selection 

hold 500–1,000 eggs. Some of the eggs will survive 

and develop into adult spiders. Some will not. 

STRUGGLE TO SURVIVE Some tarantulas may 

be caught by predators, such as this wasp. Other 

tarantulas may starve or get a disease. Only some 

of the tarantulas will survive to adulthood. 


4 

INHERITED VARIATION Every individual has 

its own combination of traits. Each tarantula is 

similar to, but not identical to, its parents. 

SUCCESSFUL REPRODUCTION The tarantulas 

that are best adapted to their environment are 

likely to have many offspring that survive. 



The most likely individuals in a population to survive and reproduce are 

A the largest ones. B the well-adapted ones. 

C the ones with the D the oldest ones. 

most DNA. 

The correct answer is B. Individuals whose traits match the environment tend to 

survive more than others. Depending on the environment, size (Answer A) can help or 

hinder survival. All individuals of a species have the same amount of DNA (Answer C). 

Organisms must survive when they are young in order to become older (Answer D). 


25 






1. Over time, a population will be made up of more individuals with 

characteristics that will 

A help them survive. 

B not help them survive. 

C keep them from reproducing. 

D make them attractive to predators. 

2. Two populations have developed into two species when 

F the populations are separated. 

G the populations look different. 

H the populations can no longer interbreed. 

J the populations adapt. 

3. How does adaptation help an organism? 

A It helps the organism change colors. 

B It improves its ability to survive and reproduce. 

C It improves its ability to change species. 

D It helps the organism become a fossil. 

4. a. Explain how the meanings of population and species differ. 

b. Using the terms population and species, describe what is meant by 

the term speciation. 


26 





GLE 0807.5.5 Describe the importance of maintaining Earth’s biodiversity. 


The ecosystem of an area can be badly damaged or destroyed by natural forces, such 

as fire, glaciers, or by human activity. Generally, a few plants start to inhabit the area. 

Following these plants, more and generally larger organisms become established over 

years or decades. The rebuilding of living communities in these areas is called succession. 

In the early stages of succession, only a few species grow in an area. These species 

grow quickly and make many seeds that scatter easily. However, all species are 

vulnerable to disease, disturbances, and competition. As a community matures, it 

may be dominated by well-adapted, slow-growing climax species. Furthermore, as 

succession proceeds, more species may become established. The variety of species 

that are present in an area is referred to as biodiversity. 

Biodiversity is important to communities of organisms. For example, a forest that 

has a high degree of biodiversity is less likely to be destroyed by an invasion of 

insects. Most plant-damaging insects prefer to attack only one species of plants. The 

presence of a variety of plants will lessen the impact and spread of invading insects. 

A mature community may not always be a forest. A mature community simply has 

organisms that are well adapted to live together in the same area over time. Any 

healthy ecosystem – such as forest, desert, marine, or tundra ecosystems – includes 

a diverse community of animals and plants that interact with one another. 

Biodiversity is also important for the whole planet. Because Earth has such a wide 

variety of climates, it is important to have many different and diverse ecosystems. 

A greater range of plants and animals allows local and global ecological systems to 

recover when they are damaged. 




Which of the following statements best describes a community with high 

biodiversity? 

A has many plants and animals of a few species 

B includes pine trees and maple trees 

C consists of many different species interacting with one another 

D has very few predators 

The correct answer is C. A diverse community has many different species that 

function together. A community with only a few species (Answer A) has very little 

diversity. Answer D is incorrect because predators are an important part of most 

ecosystems. Any type of ecosystem can include a diverse community, not just forests 

(Answer B). 


27 






1. Which of the following does not cause a loss of biodiversity? 

A removing all of the pine trees in a forest as timber 

B introducing a new predator that has no natural controls 

C replacing a natural species that has been removed in the past 

D plowing a meadow to plant crops 

2. One of the most common plants in a recently abandoned farm field 

would be 

F oak or maple trees. 

G pine trees. 

H crab grass. 

J mosses. 

3. The pioneer species on bare rock are usually 

A lichens. 

B mossses. 

C small trees. 

D pine trees. 

4. a. Why is a community with high biodiversity more likely to recover 

from damage quickly? 

b. What types of organisms are most important in order to maintain 

biodiversity? Explain your answer. 


28 





GLE 0807.5.6 Investigate fossils in sedimentary rock layers to gather 

evidence of changing life forms. 


Evidence that organisms have changed over time is buried within the layers of 

Earth’s crust. The remains or imprints of once-living organisms found in layers of 

rock are called fossils. Fossils usually form when a dead organism is covered by a 

layer of sediment. Over time, more sediment settles on top of the organism. Minerals 

in the sediment may seep into the organism and gradually replace the organism 

with stone. 

Scientists have constructed a fossil record, which organizes fossils by their estimated 

ages and physical similarities. Fossils found in newer layers of Earth’s crust tend 

to be similar to present-day organisms. Fossils from older layers are less similar to 

present-day organisms. The older fossils are of earlier life forms, which may not exist 

anymore. 

Scientists observe that all living organisms have characteristics in common and 

inherit characteristics in similar ways. Evidence of common ancestors can be found 

in fossils and in living organisms. The fossil record describes the order in which 

species have existed. As populations change over time, new species form. Newer 

species descend from older species. The fossil record is a map of the changes that 

have occurred as species have changed over time. 




What can scientists learn from studying the relationships between fossils? 

A how old all rock layers are 

B how life has changed over time 

C how many relatives fossils have had 

D how many organisms there are 

The correct answer is B. Fossils provide evidence of how life has changed over time. 

The age of fossils is determined from the age of the rock around them (Answer A). 

Because many species do not leave fossils, the fossil record does not tell how many 

organisms lived or how many relatives they had (Answers C and D). 


29 






1. Scientists use fossil evidence to prove which of the following? 

A Organisms have been changing over time. 

B All of the organisms that have ever lived on Earth have been discovered. 

C Organisms of the past are identical to those living today. 

D Organisms with bones and shells are more common than those that lack 

these structures. 

2. Where can evidence of common ancestors be found? 

F in current characteristics of living beings 

G in characteristics found in the DNA of living beings 

H in fossil record evidence about the order in which species existed 

J in fossil record evidence about the time when species existed 

3. When organisms die and are quickly buried by sediment 

A their rate of decay speeds up. 

B their rate of decay slows. 

C the organisms do not decay. 

D the organisms decay immediately. 

4. a. How do scientists use fossils to learn more about Earth’s past? 

b. What evidence do fossils provide about plants and animals? 


30 



Grade 8 – Physical Science: 

Standard 9 – Matter 

GLE 0807.9.1 Understand that all matter is made up of atoms. 


Take a piece of an element, such as a sheet of aluminum foil. Cut it in half and then 

cut that piece in half. What happens if you keep cutting indefinitely? Eventually, you 

would get to a piece so small that it could not be cut and still be aluminum. Those 

final cuts would not be made with scissors, though, because that final piece – a 

single atom – is extremely tiny. All matter is made of atoms. In fact a penny is made 

up of about 20,000,000,000,000,000,000,000 atoms of copper and zinc. (That’s more 

than 3,000,000,000,000 times more atoms than there are people on Earth.). 

The basic particles of every element are its atoms. Atoms are composed of three 

types of particles—protons, electrons, and neutrons. Protons and neutrons form the 

central part of the atom, the nucleus, and they make up almost all of its mass. Every 

atom of a particular element has the same number of protons, but the number of 

neutrons can vary. The number of protons is the atomic number of the element, 

which identifies the element. 

Parts of an Atom 

ELECTRONS are negatively charged 

particles found in electron clouds outside 

the nucleus. The size of the electron clouds 

determines the size of the atom. 

The NUCLEUS is the small, 

dense, positively charged 

center of the atom. It contains 

most of the atom’s mass. 

The diameter of the 

nucleus is 1/100,000 the 

diameter of the atom. 


PROTONS are positively 

charged particles in the 

nucleus of an atom. 

NEUTRONS are particles 

in the nucleus of an atom 

that have no charge. 



The atomic number of an element is determined by the number of which 

particles in the nuclei of its atoms? 

A protons B neutrons 

C electrons D protons and neutrons 

The correct answer is A. The number of protons determines the atom’s identity. 

The number of neutrons in the atoms of an element can vary (Answers B and D). 

Although an atom has the same number of protons and electrons, the electrons are 

not located in the nucleus (Answer C). 


31 






1. Which of the following particles has a positive electrical charge? 

A electron 

B proton 

C neutron 

D atom 

2. Which of the following statements describes elements? 

F All of the particles in the same element are different. 

G Elements can be broken down into simpler substances. 

H Elements have unique sets of properties. 

J Elements cannot be joined together in chemical reactions. 

3. In the figure below, the black circles represent neutrons. 

What is the atomic number of the atom shown? 

A 3 

B 4 

C 7 

D 11 

4. a. If atoms can be divided into other particles, why do we say that an 

atom is the smallest piece of an element? 

b. What limits the number of elements that can exist? 


32 





GLE 0807.9.2 Explain that matter has properties that are determined by the 

structure and arrangement of its atoms. 


All materials have physical and chemical properties that make them different from 

other matter. Physical properties include density, melting point, and boiling point. 

Chemical properties include how the material combines with other materials, such 

as when a material burns. The properties of a substance are determined by the atoms 

that it is composed of and how those atoms are arranged relative to one another. 

SOLUBILITY 

(sahl yoo BIL 

uh tee) is the 

ability of a 

substance 

to dissolve 

in another 

substance. 

Flavored drink 

mix dissolves 

in water. 

THERMAL 

CONDUCTIVITY 

(kahn duhk TIV 

uh tee) is the 

rate at which 

a substance 

transfers heat. 

Plastic foam is a 

poor conductor. 

Examples of Physical Properties 

STATE is the 

physical form 

in which a 

substance 

exists, such as 

a solid, liquid, 

or gas. Ice is 

water in the 

solid state. 

DUCTILITY (duhk TIL 

uh tee) is the ability of a 

substance to be pulled 

into a wire. Copper is 

often used to make wiring 

because it is ductile. 

DENSITY is the 

mass per unit 

volume of a 

substance. Lead 

is very dense, so 

it makes a good 

sinker for a 

fishing line. 

MALEABILITY (mal ee uh 

BIL uh tee) is the ability of 

a substance to be rolled or 

pounded into thin sheets. 

Aluminum can be rolled 

into sheets to make foil. 

Chemical properties are properties of matter that describe a substance’s ability to 

change into a new substance. Chemical properties describe how and under what 

circumstances a particular substance will change into a new substance. Generally, 

chemical properties describe how a substance is able to interact with other substances. 




Which of the following properties is a chemical property? 

A flammability B malleability 

C hardness D color 

The correct answer is A. When a substance burns, it combines with oxygen in the air, 

so flammability is a chemical property. All of the other properties (Answers B, C, and 

D) are physical properties that do not involve combining the substance with another 

material. 


33 






1. Which of these is a physical property of iron? 

A soluble in water 

B conducts electricity 

C colorless gas 

D combines with oxygen to form rust 

2. Which of the following statements does not describe a physical 

property of a piece of chalk? 

F Chalk is a solid. 

G Chalk can be broken into pieces. 

H Chalk is white. 

J Chalk will bubble in vinegar. 

3. Which of the following is a characteristic property? 

A density 

B chemical reactivity 

C solubility in water 


4. a. What are some of the physical properties of a sheet of paper? 

b. What is a chemical property of paper? 


34 





GLE 0807.9.3 Interpret data from an investigation to differentiate between 

physical and chemical changes. 


Substances change. Sometimes, they change physically, such as when ice melts. 

Sometimes, they change chemically, such as when a substance breaks down and 

releases a gas, when a substance forms a solid, or when a substance changes color. 

A physical change is any change in which the physical properties of a substance 

change but the substance’s identity does not. Physical properties include shape, 

color, odor, texture, mass, volume, density, buoyancy, solubility, and boiling point. 

For example, physical changes can be used to separate a mixture of the solids sulfur 

and sodium chloride (table salt). Water is added to the mixture. The salt dissolves in 

water, while the sulfur floats on top. 

In a chemical change, new substances form, and their identities and properties 

differ from the identities and properties of the original matter. Chemical changes 

happen when bonds between atoms are broken, or new bonds are formed to make 

new substances. These changes are also called chemical reactions. A variety of clues 

indicate chemical changes. A change in color or the production of heat, sound, 

or light may indicate a chemical change. For example, fizzing and foaming signal 

that a chemical change happens when vinegar and baking soda are mixed. New 

substances, including carbon dioxide gas, form. Another example is the burning of 

wood, which has the chemical property of flammability. As wood and oxygen react, 

they change into new substances having different properties from the original wood 

and oxygen. Unlike physical changes, most chemical changes are not reversible. 




Which of the following is not an example of a chemical change? 

A wood burning 

B adding baking soda to vinegar 

C separating a salt water solution 

D photosynthesis 

The correct answer is C. Separating salt and water does not change either substance. 

When wood burns (Answer A), vinegar and baking soda form carbon dioxide 

(Answer B), or carbon dioxide and water are combined in photosynthesis 

(Answer D), new substances are formed, so a chemical change takes place. 


35 






1. A physical change can affect which of the following characteristics 

of matter? 

A size 

B volume 

C shape 


2. Which process causes substances to react to form one or more new 

substances? 

F chemical change 

G physical change 

H evaporation 

J freezing 

3. When sand is heated to high temperatures and forms molten glass, 

it is an example of 

A a physical change. 

B a chemical change. 

C a material change. 

D a physical reaction. 

4. a. List at least five properties that can be tested without altering the 

identity of the matter. 

b. Why is dissolving salt in water a physical change? 


36 





GLE 0807.9.4 Distinguish among elements, compounds, and mixtures. 


Elements are materials with only one kind of atom. Because most elements take part in 

chemical changes fairly easily, they are rarely found alone in nature. Instead, they are 

found combined with other elements as compounds. A compound is a pure substance 

composed of two or more elements that are chemically combined. Elements combine 

by reacting, or undergoing a chemical change, with one another. 

Matter that contains two or more pure substances – elements or compounds – is called 

a mixture. A homogeneous mixture is the same throughout. In a heterogeneous mixture, 

the substances are not evenly mixed. The physical properties of the components of 

a mixture include size, shape, texture, mass, volume, density, solubility, and boiling 

point. These physical properties can often be used to separate a mixture into its original 

substances. Apple juice, for example, is a mixture that includes water, sugars, and 

acids. The apple juice mixture can be physically separated by evaporating the water. 

In trying to separate a mixture of iron and aluminum, iron has the physical property of 

being magnetic while aluminum does not. This property causes the iron to be 

attracted to the magnet so that it can be separated from a mixture of iron and aluminum. 




Matter that can be physically separated into two or more pure substances 

is called 

A a solid. B a compound. 

C a mixture. D an element. 

The correct answer is C, a mixture. Elements (Answer D) and compounds (Answer 

B) are pure substances that cannot be physically separated into component parts. 

Solid (Answer A) is not matter. It is a description of a physical property. 


37 






1. A mixture composed of substances that are spread evenly throughout 

is called 

A a liquid. 

B a suspension. 

C homogeneous. 

D heterogeneous. 

2. In a mixture, which of the following is always true? 

F It is composed of two or more pure substances. 

G It contains dissolved solids. 

H It is a liquid. 

J It cannot be separated into individual components. 

3. The elements in a compound 

A join in a specific ratio according to their masses. 

B combine by reacting with one another. 

C can be separated by chemical changes. 


4. a. Explain how elements combine to create compounds. 

b. Describe what makes a compound unique. 


38 





GLE 0807.9.5 Apply the chemical properties of the atmosphere to illustrate a 

mixture of gases. 


Earth is surrounded by a mixture of gases called the atmosphere. Earth’s 

atmosphere extends outward some 500 km from the surface of Earth. However, 

the majority of atmospheric gases is concentrated within 12 km of Earth’s surface. 

The atmosphere is not a pure substance. It can be separated into its components 

by cooling the gases to very low temperatures so that they become liquid. Nitrogen, 

N2 , makes up 78% of the atmosphere by volume. Nitrogen is put into the atmosphere 

mostly by microorganisms and volcanic eruptions. Nitrogen does not react readily 

with other materials. In chemical manufacturing processes, it is often used to provide 

an inert atmosphere inside containers to prevent fires and explosions. Oxygen, O2, 

makes up 21% of the atmosphere by volume. Oxygen is released by plants through 

photosynthesis. Oxygen is used by both plants and animals during respiration. 

Combustion is the combination of oxygen with other substances. If you cover a candle 

with a jar, it will stop burning as soon as the oxygen is consumed. Other important 

gases in the atmosphere include water vapor, carbon dioxide, and argon. These three 

gases make up nearly 1% of atmospheric gases. Argon is even less reactive than nitrogen. 

If you remove any of the gases in the air, including nitrogen, you do not change the 

appearance of the air. However each gas has different physical and chemical properties. 

Nitrogen 

78% 


Nitrogen, the most common atmospheric gas, 

is released when dead plants and dead animals 

break down and when volcanoes erupt. 

Oxygen 

21% 

1% 

Oxygen, the second most common 

atmospheric gas, is released by 

phytoplankton and plants. 

The remaining 1% of the 

atmosphere is made up of argon, 

carbon dioxide, water vapor, and 

other gases. 



Which of the following best describes air? 

A compound B homogeneous mixture 

C heterogeneous mixture D element 

The correct answer is B. In a homogeneous mixture the components are evenly 

mixed and cannot be easily separated by physical means. In a heterogeneous 

mixture (Answer C), the components are not completely mixed. The components 

of air are compounds and elements (Answers A and D). 


39 






1. Why is it incorrect to say that when something burns, it combines 

with air? 

A Air is not involved in burning. 

B Only one component of the mixture that we call air reacts when 

something burns. 

C Nitrogen prevents materials from burning in pure air. 

D Air contains carbon dioxide. 

2. About what percentage of the air around you is composed of elements? 

F 0% 

G 21% 

H 78% 

J 99% 

3. Which of the components of air is most reactive? 

A nitrogen 

B oxygen 

C carbon dioxide 

D argon 

4. a. How can you remove oxygen from air by chemical means? 

b. What is the source of most of the oxygen in the atmosphere? 


40 





GLE 0807.9.6 Use the Periodic Table to determine the characteristics of 

an element. 


The elements are organized into a chart called the Periodic Table of Elements. Each 

horizontal row of elements on the Periodic Table is called a period. The physical and 

chemical properties of elements in a row follow a repeating pattern as you move across 

the period. Each vertical column of elements on the Periodic Table is called a group. 

Elements in the same group generally have similar chemical and physical properties. 

Elements are classified as metals, nonmetals, and metalloids, according to their 

properties. The zigzag line on the Periodic Table can help you recognize which 

elements are metals, which are nonmetals, and which are metalloids. Metals are 

found to the left of the zigzag line on the Periodic Table. Atoms of most metals have 

few electrons in their outer energy level. Most metals are solid at room temperature. 

Nonmetals are found to the right of the zigzag line on the Periodic Table. Atoms of 

most nonmetals have an almost complete set of electrons in their outer level. More 

than half of the nonmetals are gases at room temperature. Metalloids, also called 

semiconductors, are the elements that border the zigzag line on the Periodic Table. 

Atoms of metalloids have about half of a complete set of electrons in their outer energy 

level. Metalloids have some properties of metals and some properties of nonmetals. 

H 

1 2 

Li 

Na 

K 

Rb 

Cs 

Fr 

Be 

Mg 

Ca 

Sr 

Ba 

Ra 

Sc 

Y 

La 

Ac 


3 4 5 6 7 8 9 10 11 12 

Ti 

Zr 

Hf 

Rf 

V 

Nb 

Ta 

Db 

Cr 

Mo 

W 

Sg 

Mn 

Tc 

Re 

Bh 

Fe 

Ru 

Os 

Hs 

Co 

Rh 

Ir 

Mt 

Ni 

Pd 

Pt 

Ds 

Cu 

Ag 

Au 

Uuu 

Zn 

Cd 

Hg 

Uub Uut 

13 14 15 16 17 

B 

Al 

Ga 

In 

Tl 

C 

Si 

Ge 

Sn 

Pb 

N O F 

Sb 

Bi 

Uuq Uup 



As you move from left to right across the elements in a period in the Periodic 

Table, the properties of the elements 

A are identical. B change gradually. 

C become more alike. D become more characteristic of metals. 

The correct answer is B. Properties of elements change gradually across the table in 

a periodic way. No two elements have identical properties (Answer A). The amount 

of difference between adjacent elements is greatest toward the two ends of the table 

and less in the center (Answer C). Metallic characteristics decrease from left to right 

on the table (Answer D). 


41 

P 

As 

S 

Se 

Te 

Po 

Cl 

Br 

I 

At 

18 

He 

Ne 

Ar 

Kr 

Xe 

Rn 






1. Nonmetals are found on the right side of the Periodic Table. Which of 

the following best describes a physical property of nonmetals? 

A lustrous silver color 

B poor conductor of electric current 

C flattens when hit with a hammer 

D solid at room temperature 

2. Which of the following elements do not usually react with other 

elements? 

F carbon group 

G noble gases 

H halogens 

J alkali metals 

3. The alkali metals are the most reactive metals because 

A they are never found uncombined in nature. 

B they have only one electron in their outer level. 

C they have only two electrons in their outer level. 

D their outer level is filled. 

13 

5 

B 

10.81 

13 

Al 

26.98 

Segment of the Periodic Table 

14 

6 

C 

12.01 

14 

Si 

28.09 

15 

7 

N 

14.01 

15 

P 

30.97 

16 

8 

O 

16.00 

16 

S 

32.06 

17 

9 

F 

19.00 

17 

Cl 

35.45 

18 

2 

He 

4.00 

10 

Ne 

20.18 

18 

Ar 

39.95 

4. a. Which of the elements on this segment are noble gases? 

b. Which two elements on this segment of the table are most reactive. 

Explain your answer. 


42 





GLE 0807.9.7 Explain the Law of Conservation of Mass. 


Atoms are never lost or gained in a chemical reaction. They are just rearranged. 

Every atom in the reactants becomes part of the products. When writing a chemical 

equation, make sure that the total number of atoms of each element in the reactants 

equals the total number of atoms of that element in the products. This process is 

called balancing the equation. 

Balancing equations comes from the work of a French chemist, Antoine Lavoisier. In 

the 1700s, Lavoisier found that the total mass of the reactants was always the same 

as the total mass of the products. Lavoisier’s work led to the Law of Conservation 

of Mass. This law states that mass is neither created nor destroyed in chemical and 

physical changes. This law means that the total mass of the reactants is the same 

as the total mass of the products. Also, because the atoms are not changed by 

the reaction, the total mass of each element is the same in the products as in the 

reactants. So, a chemical equation must show the same numbers and kinds of atoms 

on both sides of the equation’s arrow even though the atoms are rearranged. 


2H2 + O2 

O 

H H H H 

O 

O 

H H 

2H 2O 

O 

H H 



What happens to atoms in a chemical reaction? 

A atoms are gained 

B atoms are rearranged 

C atoms are lost 

D atoms lose mass 

The correct answer is B. According to the law of conservation of mass, atoms do not 

change during a chemical reaction although their arrangement changes. Atoms are 

therefore, neither lost nor gained (Answers A and C). Although nuclear reactions can 

change the mass of an atom, chemical reactions do not (Answer D). 


43 






1. Which of the following is true for all chemical reactions? 

A There are always more atoms before the reaction than after the reaction. 

B There are always more atoms after the reaction than before the reaction. 

C The number of atoms after the reaction is always equal to the number of 

atoms before the reaction. 

D The number of molecules after the reaction is always equal to the 

number of molecules before the reaction. 

2. Which statement below summarizes the Law of Conservation of Mass? 

F Matter cannot be created or destroyed in a chemical reaction. 

G Matter is converted into energy in a chemical reaction. 

H Matter and energy are two forms of the same thing. 

J The total mass of reactants is usually the same as total mass of the 

products. 

3. When logs burn on a fire, the mass of the ash formed is much less than 

the mass of the log. Why does this not violate the Law of Conservation 

of Mass? 

A Some of the mass is converted to heat. 

B The ash is denser so the total mass is the same as the log. 

C The reaction is not a chemical reaction. 

D Most of the reaction products are gases so their mass is not part of the ash. 

4. a. Write an original definition for chemical change. 

b. Give an explanation of the process of a chemical change and give 

one example. 


44 





GLE 0807.9.8 Interpret the events represented by a chemical equation. 


Chemical changes happen when bonds between atoms are broken, or new bonds 

are formed to make new substances. These changes are also called chemical 

reactions. A chemical equation summarizes the chemical change. 

An example of a chemical reaction is burning charcoal. Charcoal is mostly pure 

carbon, represented by the chemical symbol C. Carbon reacts with oxygen when it 

burns. Oxygen exists in air as a molecule with two oxygen atoms. The number 2 is 

used as a subscript to indicate that there are two atoms of oxygen in each molecule: 

C + O2 → CO2 

When sodium reacts with chlorine, it forms sodium chloride. There are two atoms of 

chlorine in a chlorine molecule, so each chlorine molecule reacts with two sodium 

atoms. This is indicated by a number, called a coefficient, in front of the symbol for 

sodium. 

2Na + Cl2 → 2NaCl 

Fizzing and foaming signal that a chemical change happens when vinegar and 

baking soda are mixed. The chemical equation shows that one of the products is 

carbon dioxide, which is a gas at room temperature. As the carbon dioxide escapes 

the solution, it makes the fizzing occur. 

2CH3COOH + Na2CO3 → 2CH3COONa + CO2 + H2O 

The numbers in front of each compound tell how many molecules of the compound 

are involved in the reaction. The equation shows that the same number of each type 

of atom exists in the products as in the reactants. 




In the chemical equation for the mixing of vinegar and baking soda above, 

how many atoms of carbon are involved? 

A 2 B 3 

C 5 D 6 

The correct answer is C. The reactants are two molecule of vinegar, each of which 

has 2 carbon atoms and an additional carbon atom in the sodium carbonate. The 

products are two molecules of sodium acetate (4 carbon atoms), one molecule of 

carbon dioxide (1 carbon atom) and one molecule of water (no carbon atoms). 

Answer A is the number of different reactants. Answer B does not account for the 

second molecule of acetic acid. Answer D adds an extra carbon atom. 


45 






1. How many oxygen atoms are involved in the combustion of sugar 

shown by the equation below? 

A 6 

B 8 

C 12 

D 18 

C6H12O6 + 6O2 → 6CO2 + 6H2O 

2. What does a coefficient in a chemical equation represent? 

F the number of atoms of a particular element in a molecule 

G the number of atoms of a particular element the chemical reaction 

H the number of molecules of a particular compound in the reaction 

J the number of grams of a particular compound in the reaction 

3. What type of reaction does the following equation represent? 

FeS + 2HCl → FeCl2 + H2S 

A synthesis reaction 

B double-displacement reaction 

C single-displacement reaction 

D combustion reaction 

4. a. Why can the subscript not be changed to balance a chemical 

equation? 

b. What do you change to balance a chemical equation? Explain 

your answer. 


46 





GLE 0807.9.9 Explain the basic difference between acids and bases. 


An acid is any compound that increases the number of hydronium ions, H3O + , when 

dissolved in water. Hydronium ions form when a hydrogen ion, H + , separates from 

the acid and bonds with a water molecule, H2O. The sour taste of lemons, limes, and 

other citrus fruits is a result of citric acid. A sour taste is one of the properties of an 

acid. A chemical property of many acids is a reaction with some metals to produce 

hydrogen gas. 

A base is any compound that increases the number of hydroxide ions, OH – , when 

dissolved in water. For example, sodium hydroxide breaks apart to form sodium ions 

and hydroxide ions. The properties of a base solution include a bitter taste and a 

slippery feel. Strong bases are used in drain cleaners because they react with grease, 

hair, and other organic materials. 

The hydronium and hydroxide ions of acids and bases react with one another to 

form water, which is neutral, neither acidic nor basic. Other ions from the acid 

and base dissolve in the water. If the water evaporates, these ions join to form a 

compound called a salt. A salt is an ionic compound formed from the positive ion of 

a base and the negative ion of an acid. 

The pH scale is used to describe how acidic or how basic a substance is. The pH of a 

solution is a measure of the hydronium ion concentration in the solution. 

pH Values of Common Materials 

Lemon 

juice 


Increasing acidity Increasing basicity 

1 2 3 4 5 6 7 8 9 10 11 12 13 

Soft 

drink 

Milk 

Human 

saliva 

Acid rain Clean rain 

Sea 

water 

Tap water 

Detergents Household 

ammonia 

Human stomach contents 



What ion is present in high concentration in every strong acid solution? 

A H + B OH – 

C H3O + D H2O 

The correct answer is C. Every acid contains hydronium ions. Although the acid 

produces H+ ions (Answer A), they react with water in solution. Hydroxide ions 

(Answer B) are present in solutions of bases. Water (Answer D) is present in the 

solution, but it is not an ion. 


47 






1. Which of the following describes a property of bases? 

A feels slippery 

B tastes sour 

C reacts with metal to produce hydrogen 

D turns blue litmus paper red 

2. What are the products of a neutralization reaction? 

F acid and metal 

G water and hydrogen 

H salt and hydrogen 

J salt and water 

3. How does an increase in hydronium ions affect the pH of a solution? 

A raises the pH 

B lowers the pH 

C does not affect the pH 

D any of the above, depending on concentration 

4. a. Why is the reaction of an acid with a base called a neutralization 

reaction? 

b. What would you use to neutralize a solution of sodium hydroxide? 


48 




Standard 12 – Forces of Nature 

GLE 0807.12.1 Investigate the relationship between magnetism and electricity. 


Electricity and magnetism are related forces. When a compass is held close to a wire 

with an electric current flowing through it, the compass needle no longer points 

north because an electric current produces a magnetic field. A compass needle is a 

magnet. It moves from its north-south orientation only when it is in a magnetic field 

different from Earth’s. The motion of electrons in the wire produces a magnetic field 

around the wire. 

When a magnet is in motion relative to a wire, the opposite effect occurs. The 

magnetic field causes charged particles to move inside a conductor, such as a 

copper wire. However, this only occurs when the magnet is moving or when the 

conductor is moving. It is the relative motion of wire and the magnetic field that 

causes electrons to move, and it is this motion that generates an electric current. The 

process by which an electric current is made by changing a magnetic field is called 

electromagnetic induction. 

An electric generator in a power plant uses electromagnetic induction to change 

mechanical energy into electrical energy. The energy that generators convert into 

electrical energy comes from different sources. The source in nuclear power plants 

is thermal energy from a nuclear reaction. The energy boils water into steam. The 

steam turns a turbine. The turbine turns the magnet of the generator, which induces 

an electric current and generates electrical energy. Other kinds of power plants 

burn fuel such as coal or gas to release thermal energy. Hydroelectric plants use the 

energy of falling water to turn a turbine. 




Which of the following will induce an electric current in a wire? 

A moving a magnet into a coil 

B moving a wire between the poles of a magnet 

C turning a loop of wire between the poles of a magnet 


The correct answer is D. Electromagnetic induction occurs when a conductor, 

such as a metal wire, is in motion relative to a magnetic field. It does not matter 

whether the conductor moves or the magnet moves as long as they move in relation 

to each other. 


49 






1. An electric motor uses an electromagnet to change 

A mechanical energy into electrical energy. 

B magnetic fields in the motor. 

C magnetic poles in the motor. 

D electrical energy into mechanical energy. 

2. What happens to the magnetic field around a wire if you reverse the 

connection between the wire and the poles in a battery? 

F The magnetic field is not affected. 

G The magnetic field disappears. 

H The magnetic field becomes stronger. 

J The magnetic field reverses direction. 

3. How do electric power plants generate a current? 

A magnetic reversal 

B magnetic induction 

C thermal induction 

D electromechanical induction 

4. a. Why do power plants need a source of kinetic or thermal energy? 

b. What type of materials could be used in the coils of an electric 

generator? 


50 





GLE 0807.12.2 Design an investigation to change the strength of an 

electromagnet. 


A single loop of wire carrying a current does not have a very strong magnetic 

field. However, suppose you form many loops into a coil. The magnetic fields of the 

individual loops will combine to make a much stronger field. A solenoid is a coil of 

wire that produces a magnetic field when carrying an electric current. In fact, the 

magnetic field around a solenoid is very similar to the magnetic field of a bar magnet. 

The strength of the magnetic field of a solenoid increases as more loops per meter are 

used. The magnetic field also becomes stronger as the current in the wire is increased. 

The ends of the solenoid are like 

the poles of a bar magnet. 

An electromagnet is made up of a solenoid wrapped around an iron core. The 

magnetic field of the solenoid makes the domains inside the iron core line up. 

The magnetic field of the electromagnet is the field of the solenoid plus the field 

of the magnetized core. As a result, the magnetic field of an electromagnet may be 

hundreds of times stronger than the magnetic field of just the solenoid. 

To make an electromagnet stronger, you can increase the number of loops per 

meter in the solenoid. You can also increase the electric current in the wire. Some 

electromagnets are strong enough to lift a car or levitate a train. 




Which of the following changes will increase the strength of a solenoid? 

A add coils 

B remove coils 

C decrease the current 

D reverse the current 

The correct answer is A. Additional coils increase the strength of an electromagnet. 

Removing coils (Answer B) or decreasing the current (Answer C) will decrease its 

strength. Reversing the direction of the current (Answer D) will change the direction 

of the magnetic field but not its strength. 


51 






1. Look at the solenoids and electromagnets shown below. Identify which 

of them has the strongest magnetic field. 

A 

B 

C 

D 

2. The magnetic field of a solenoid can be increased by 

F adding more loops per meter. 

G increasing the current. 

H putting an iron core inside the coil to make an electromagnet. 

J all of the above. 

3. a. In what way is an electromagnet similar to a bar magnet? 

b. How does an electromagnet differ from a bar magnet? 


52 





GLE 0807.12.3 Compare and contrast Earth’s magnetic field to that of a 

magnet and an electromagnet. 


A compass points to the north because Earth itself is one giant magnet. In fact, Earth 

behaves as if it has a bar magnet running through its center. The poles of this imaginary 

magnet are located near Earth’s geographic poles. If you put a compass near a bar 

magnet, the marked end of the needle points to the south pole of the magnet. Opposite 

poles of magnets attract each other. The tip that points to the north is the needle’s 

north pole. Therefore, the point of a compass needle is attracted to the south pole of 

a magnet. A compass needle points north because the magnetic pole of Earth that 

is closest to the geographic North Pole is a magnetic south pole. The compass needle 

points to the north because its north pole is attracted to a very large magnetic south pole. 

Although you can think of Earth as having a giant bar magnet through its center, 

there isn’t really a magnet there. The temperature of Earth’s core is very high. The 

atoms in it move too violently to stay lined up in domains. Scientists think that 

Earth’s magnetic field is made by the movement of electric charges in the Earth’s 

core. The Earth’s core is made mostly of iron and nickel. The inner core is solid 

because it is under great pressure. The outer core is liquid because the pressure is 

not as high. As Earth rotates, the liquid in the core flows. Charged particles move, 

which makes a magnetic field. 

The strength of a magnetic field decreases rapidly with distance from the magnet. 

On the surface of the planet, Earth’s magnetic field is not very strong compared to 

that of a nearby electromagnet, or even that of a permanent bar magnet. Even so, it 

is very important. The magnetic field prevents charged particles from the sun, which 

could harm living things, from reaching the surface. 




Where is the south pole of Earth’s magnetic field? 

A at the geographic south pole 

B near the geographic south pole 

C at the geographic north pole 

D near the geographic north pole 

The correct answer is D. The magnetic south pole is actually near the geographic 

north pole because a compass needle is marked with a “north-seeking” pole. The 

geographic north pole is actually in Antarctica (Answers A and B). Because the 

magnetic field is not exactly aligned with the axis of rotation, the magnetic poles are 

not located exactly at the geographic poles (Answers A and C). 


53 






1. Most of the charged particles in the solar wind are deflected before they 

reach Earth’s surface. What causes this deflection? 

A an electric field 

B a magnetic field 

C Earth’s gravity 


2. What is the source of Earth’s magnetic field, according to current 

theories? 

F a large bar magnet 

G alignment of the magnetic domains of the inner core 

H moving metal ions in the outer core 

J magnetic domains in the lithosphere 

3. Why is a small bar magnet able to deflect a compass from Earth’s large 

magnetic field? 

A The bar magnet is much closer to the compass than the source of 

Earth’s field. 

B The bar magnet is made of magnetic material, and Earth is not. 

C Solar wind absorbs Earth’s magnetic field. 

D The lithosphere shields the compass from Earth’s magnetic field. 

4. a. The moon has a completely solid core. Based on current theories 

about Earth’s magnetic field, why would the moon not have a 


b. What could cause Earth’s magnetic field to reverse directions? 


54 





GLE 0807.12.4 Identify factors that influence the amount of gravitational force 

between objects. 


All matter has mass. Gravity is a result of mass. Therefore, all matter is affected by 

gravity. That is, all objects experience an attraction toward all other objects. This 

gravitational force pulls objects toward each other. According to the Law of Universal 

Gravitation, all objects in the universe attract each other through gravitational force. 

The size of the force depends on the masses of the objects and the distance between 

the objects. The gravitational force is stronger when the masses are greater or when 

the objects are closer together. 

Relationship between gravitational attraction and distance 

The mass of an object is a measure of the amount of matter it contains, so mass 

is a constant characteristic of a particular object. Weight is a measure of the force 

of gravity on the object, which is proportional to the mass. Therefore, weight is a 

function of the masses of the object and the larger object to which it is attracted, so 

weight can vary. A person would not weigh as much on the moon as on Earth. 




Why don’t you notice the gravitational pull of objects towards you or your 

body towards objects, such as a pencil? 

A The force of gravity influences only objects that are very close together. 

B You don’t notice the pull because Earth’s pull is greater. 

C Small objects exert no gravitational force. 

D The mass is too small to cause a force large enough to notice. 

The correct answer is D. The force of gravity exists between any two objects, so 

Answer C is incorrect, but it is very small when the objects are not very large. Answer 

B is incorrect because gravitational force exists between any two objects, although 

it is strongest when they are close together. Gravitational force between Earth and 

other objects does not affect their gravitational pull on one another. 


55 






1. Which of the following statements explains the Law of Universal 

Gravitation? 

A Objects in the universe attract each other through gravitational force, 

depending on their weights and the distance between them. 

B Objects in the universe attract each other through frictional force, based 

on friction and the distance of their masses. 

C Objects in the universe attract each other through gravitational force, 

depending on their masses and distance between the objects. 

D Objects in the universe attract each other through motivational forces, 

depending on their weights and masses. 

2. What is the measure of gravitational force on an object? 

F friction 

G weight 

H balance 

J mass 

3. How does mass affect gravitational force? 

A Gravitational force decreases as the masses of the objects increase. 

B Gravitational force increases as the masses of the objects increase. 

C Gravitational force increases as the masses of the objects decrease. 

D Gravitational force between objects does not depend on their masses. 

4. a. How is the acceleration of falling objects affected by gravity? 

b. Why is the acceleration, due to gravity, the same for all objects? 


56 





GLE 0807.12.5 Recognize that gravity is the force that controls the motion of 

objects in the solar system. 


An object falls toward Earth because Earth and the object are attracted to each other 

by gravity. This attraction depends on the masses of the objects and the distance 

between the objects. Both Earth and the moon are attracted to each other. Although 

it may seem as if Earth does not orbit the moon, Earth and the moon actually orbit 

each other. 

The gravitational force between you and Earth is large. Whenever you jump up, 

you are pulled back down by Earth’s gravitational force. On the other hand, the 

sun is more than 300,000 times more massive than Earth. So why doesn’t the sun’s 

gravitational force affect you more than Earth’s does? The reason is that the sun is so 

far away. 

You are about 150 million kilometers (93 million miles) away from the sun. At this 

distance, the gravitational force between you and the sun is very small. If there were 

some way you could stand on the sun, you would find it impossible to move. The 

gravitational force acting on you would be so great that you could not move any part 

of your body! 

Although the sun’s gravitational force on your body is very small, the force is very 

large on Earth and the other planets. The gravity between the sun and the planets 

is large because the objects have large masses. If the sun’s gravitational force did 

not have such an effect on the planets, the planets would not stay in orbit around 

the sun. The effect of the sun’s gravitational pull within the solar system extends to 

comets that orbit the sun at distances that are halfway to the nearest star. 




What force prevents the moon from moving away from Earth? 

A tides 

B inertia 

C electromagnetism 

D gravity 

The correct answer is D. Gravity is the force that causes two bodies to be attracted to 

one another. Tides are a result of gravity, not a cause for the bodies to stay together 

(Answer A). Inertia would cause the moon to separate from Earth if there were no 

gravitational pull between them (Answer B). Electromagnetism is not a force of 

attraction between large bodies (Answer C). 


57 






1. The Law of Universal Gravitation applies to 

A all objects in the universe. 

B only objects on Earth. 

C only the planets that orbit the sun. 

D only certain planets in the solar system. 

2. Kepler discovered that planets move faster when they 

A are farther from the sun. 

B are closer to the sun. 

C have more mass. 

D rotate faster. 

3. The solar system includes the planets, the moons of those planets, and 

the sun. Which of the following is true about the solar system? 

A The gravity of the sun does not affect the moons of the planets. 

B Other planets exert gravity on Earth but do not exert gravity on Earth’s 

moon. 

C No gravity exists between Earth and the other planets or their moons. 

D Gravity exists among all parts of the solar system and holds it together. 

4. In your own words, describe: 

a. how gravity affects objects 

b. examples of gravity at work 


58 



TCAP Test Preparation 

Practice Test A 

1. You are doing a lab experiment that involves recording the time it 

takes for a solution to change color after mixing. This table shows your 

measurements. The time for Test 3 differs significantly from the other 

measurements. How should you handle that data point? 

Test 1 2 3 4 

Time (sec) 28 31 48 30 

A Erase it from your records because it is obviously wrong. 

B Avoid writing it in your notebook in the first place. 

C Change the number so it matches the other times. 

D Record the data and try to figure out why it was different. 

2. Which of these is an example of a chemical change? 

F wood burning 

G bending a nail 

H separating a salt water solution 

J pounding a gold nugget into a sheet 


59 





3. When two populations can no longer interbreed, they have 

A developed similar traits and characteristics. 

B developed different looks. 

C developed into two species. 

D adapted to their environments. 


is called 

F a liquid. 

G a suspension. 

H homogeneous. 

J heterogeneous. 


60 





5. The picture below shows a model of a molecule. Which of the following 

cannot be determined from the model? 

A the number of atoms in the molecule 

B the number of electrons in each atom 

C the type of bonds joining the molecule 

D the physical state of the substance 

6. How does adaptation help an organism? 

F It helps the organism change colors. 

G It improves its ability to survive and reproduce. 

H It improves its ability to change species. 

J It helps the organism become a fossil. 


61 





7. Fossil records can reveal changes in the environment over time. 

Scientists have found fossils of marine animals on the tops of 

mountains in Canada. What does this tell us about the history of the 

environment in that area? 

A The mountains were once sediment at the bottom of an ocean. 

B The ancient environment in the area did not favor fossilization. 

C The ancient environment in the area was much drier than it is today. 

D The mountains formed before the animals died, and their remains 

were fossilized. 

8. What is necessary for substances to burn? 

F hydrogen 

G oxygen 

H helium 

J carbon 


62 





9. The following graphic shows a full tank of helium (A), the same tank 

after it has filled 10 balloons (B), and then the same tank after it 

has filled 20 balloons (C). Use this graphic to answer the following 

question. 

� � � 

In which tank is the greatest pressure being exerted on the tank’s inner 

surface? 

A Tank A 

B Tank B 

C Tank C 

D all three tanks have the same pressure 

10. Modern scientific explanations of how species have changed over time 

F have replaced Darwin’s theory. 

G rely on genetics instead of natural selection. 

H fail to explain how traits are inherited. 

J combine the principles of natural selection and heredity. 


63 





11. Which one of the following in the Periodic Table of Elements tells the 

physical state of an element at room temperature? 

A the atomic number 

B the color of the chemical symbol 

C the atomic mass 

D the element name 

12. Which of the following statements best describes the particles of a 

liquid? 

F The particles are far apart and moving fast. 

G The particles are close together but moving past each other. 

H The particles are far apart and moving slowly. 

J The particles are closely packed and vibrating in place. 


64 





13. In the graph below, what is happening in the range where the line is 

horizontal? 

Temperature (°C) 

30 

20 

10 

Liquid + solid 

0 

-10 

Freezing point Solid 

-20 

-30 

-40 

Time 

Liquid 

A Particles have acquired enough energy to slide past one another. 

B Particles are rearranging from a solid into a liquid. 

C Particles are rearranging from a liquid into a solid. 

D Particles are no longer locked in position. 

14. When using a triple-beam balance to measure mass, which is not 

necessary to get an accurate reading? 

F Making sure the balance is on a level surface. 

G Ensuring minimum motion is affecting the substance. 

H Allowing the balance to come to a complete rest to ensure accuracy. 

J Using your finger to keep the beam from vibrating. 


65 





15. A change that affects the physical properties but not the identity of a 

substance is 

A a reaction. 

B a reduction. 

C a chemical change. 

D a physical change. 

16. Which of the following is an example of a suspension? 

F seawater 

G gelatin 

H salad dressing 

J cooking oil 


66 





17. Based on the information in the table below, which two atoms are 

isotopes of the same element? 

A #1 and #2 

B #2 and #3 

C #3 and #4 

D #4 and #5 

Protons Electrons Neutrons 

Mystery atom #1 15 15 15 






18. What is the first step of a scientific investigation? 

F conducting an experiment 

G asking a question 

H drawing a conclusion 

J making a prediction 


67 





19. Which of the following soil properties influences how nutrients can be 

dissolved in soil? 

A soil texture 

B soil fertility 

C soil structure 

D soil pH 

20. Why does it take longer for Jupiter to orbit the sun than for Earth to 

orbit the sun? 

F Jupiter is larger than Earth. 

G Jupiter is farther from the sun than Earth. 

H Jupiter drags many more moons along with it. 

J Collisions with asteroids have slowed Jupiter’s motion. 


68 





21. Smog is a type of air pollution traditionally defined as a combination of 

smoke and fog. When composed of particles that are too small to settle 

out, smog can be considered 

A a colloid. 


C a compound. 

D an element. 

22. A beach, a cloud, and the air we breathe are examples of 

F interaction of elements. 

G distillation. 

H physical properties. 

J mixtures occurring in nature. 


69 





23. A change that affects the appearance or the state of a substance, but not 

its identity is a 

A reaction. 

B reduction. 

C chemical change. 

D physical change. 

24. Why do scientists compare fossils with living organisms? 

F to support the idea that organisms do not share ancestors 

G to support the idea that organisms have changed over time 

H to support the idea that organisms do not change over time 

J to support the idea that there are no new organisms to discover 


70 





25. To what group does a vascular plant with seeds belong? 

Nonvascular 

Mosses, liverworts, 

and hornworts 

The Four Main Groups of Living Plants 

Ferns, horsetails, 

and club mosses 

A angiosperms only 

B gymnosperms only 

C gymnosperms or angiosperms 

D ferns, horsetails, and club mosses 

Vascular 

No seeds Seeds 

Nonflowering 

Gymnosperms 

Flowering 

Angiosperms 

26. What evidence do fossils provide scientists in relation to extinctions? 

F Plants and animals have not changed for billions of years. 

G In spite of environmental changes, species remain the same. 

H Plants and animals change in response to environmental changes. 

J Earth is unchanging and has remained the same for billions of years. 


71 





27. The term heterogeneous means 

A not evenly mixed. 

B all the same. 

C unreactive. 

D pure. 

28. There are three species of birds on an island. Bird A has a heavy bill 

for eating seeds. Bird B has a pointed bill for eating insects. Bird C 

has a sharp bill for eating insects and seeds. If all insects suddenly 

disappeared, which bird or birds would be the least affected? 

F Bird A 

G Bird B 

H Bird C 

J Bird A and Bird C 


72 





29. Which of the following would most help Marie keep thorough and 

accurate records for her science project? 

A using a pen instead of a pencil for making sketches 

B performing experiments at home rather than at school 

C having a good memory for writing things down the next day 

D writing all of her observations in a single laboratory notebook 

30. A biologist notices that a species of moth has either dark coloration or 

light coloration. In a certain area where tree bark is dark, birds tend 

to prey on light moths more often than on dark moths. Which of the 

following is a reasonable conclusion? 

F The light moths are more likely to lay eggs on trees with light bark. 

G The light moths have a better chance of surviving than the dark moths. 

H More of the light moths will survive once the dark moths have adapted. 

J More of the dark moths will survive to pass their traits to their offspring. 


73 





31. The amount of matter present before a change is the same as the 

amount present after a change. This principle is called 

A the law of conservation of energy. 

B the law of conservation of mass. 

C photosynthesis. 

D a reversible change. 

32. What happens during the chemical reaction shown by this equation? 

Mg + Br 2 → MgBr 2 

F A metal and a nonmetal form a salt. 

G A metal and a nonmetal form a molecule. 

H Two nonmetal elements combine to form a compound. 

J Magnesium and bromine form a mixture. 


74 





33. Look at the pictures below. Notice the similarities between the 

structures. Some scientists think these similarities suggest which of 

the following? 

A Legs may have developed from flippers. 

B Mammals may have developed from bats. 

C A cat’s leg, a dolphin’s flipper, and a bat’s wing have identical functions. 

D Cats, dolphins, and bats may have had the same ancestor millions of 

years ago. 

34. Two populations have developed into two species when 

F the populations adapt. 

G the populations are separated. 

H the populations look different. 

J the populations can no longer interbreed. 


75 

Cat’s leg 

Dolphin’s flipper 

Bat’s wing 





35. Which of the following applies to a correctly balanced chemical 

equation? 

A Products and reactants have the same number of molecules. 

B Products and reactants have the same number of atoms for each element. 

C The subscripts are the same on both sides of the equation. 

D There are at least two products of the reactions. 

36. Matter composed of two or more pure substances is always 

F a dissolved solid. 

G a mixture. 

H a liquid. 

J a solution. 


76 





37. According to the graph below, how many years must the strontium-90 

decay before only 25% of the sample remains? 

A 112 

B 84 

C 56 

D 28 

Percent of Radioactive 

Element Remaining 

100 

75 

50 

25 

Radioactive Decay of Strontium-90 

0 28 56 84 112 

Years 

38. A scientist notices that lichen are growing on only one side of all of the 

rocks in an area. How might the scientist test her idea that the lichen’s 

growth pattern depends on the position of the growing surface? 

F Observe the rocks for a year and see if the pattern of lichen growth 

changes during that time. 

G Collect one of the rocks and place it in a laboratory to observe whether 

the lichen growth pattern changes. 

H Place new, lichen-free rocks in the area in different positions and observe 

whether lichens grow on a particular side of each new rock. 

J Turn one of the rocks around and observe whether lichens grow on the 

other side of the rock over a period of a month. 


77 





39. Which of these elements is the most reactive? 

A nitrogen 

B helium 

C neon 

D argon 

40. How might a scientist accidentally introduce bias into an experiment? 

F by working with several other scientists instead of working alone 

G by writing down only the observations that are most interesting to him 

H by having a control group that differs from the experimental groups by 

only one factor 

J by working on a scientific problem at the same time that another 

research group is working on the same problem 


78 





41. Which of these statements about the chemical equations below is true? 

1 

2 

methane + oxygen → carbon dioxide + water + energy 

CH 4 + O 2 → CO 2 + H 2 O + energy 

nitrogen + oxygen + energy → nitrogen oxide 

N 2 + O 2 + energy → N 2 O 

A Equation 1 shows an endothermic reaction. 

B Equation 2 shows an endothermic reaction. 

C Both equations show endothermic reactions. 

D There is not enough information to determine whether the reactions 

are endothermic. 

42. Which of these is an example of a technology designed to meet an 

economic need? 

F the evergreen forests of the Northwest 

G nuclear power plants that produce electric current 

H archeological excavations by university researchers 

J a report on a newly discovered species 


79 





43. The ability of substances to combine and form new substances is called 

A solubility. 

B physical reactivity. 

C chemical reactivity. 

D malleability. 

44. The process in which populations die out without leaving descendents 

is called 

F extinction. 

G erosion. 

H adaptation. 

J evidence. 


80 





45. Each graph below shows an acid being titrated with a base. Use these 

graphs to answer the following question. What can you conclude about 

these titration reactions? 

pH 

14 

13 

12 

11 

10 

9 

8 

7 

6 

5 

4 

3 

2 

1 

0 

Equivalence point 

0 10 20 30 40 50 60 

Base added to acid (mL) 

Titration Curve 

pH 

14 

13 

12 

11 

10 

9 

8 

7 

6 

5 

4 

3 

2 

1 

0 

Equivalence point 

0 10 20 30 40 50 60 

Base added to acid (mL) 

A The graph on the right shows a titration in which the base is stronger 

than the acid. 

B The graph on the left shows a titration in which the base is stronger than 

the acid. 

C Both graphs show titrations in which the base is stronger than the acid. 

D Both graphs show titrations in which the acid is stronger than the base. 

46. What ion is produced in solution by every acid? 

F hydroxide 

G hydronium 

H oxide 

J hydroxyl 


81 





47. The universal law of gravitation states that the movements of the 

planets around the sun depend on 

A the composition of the planet. 

B the planet’s mass and distance from the sun. 

C the number of moons a planet has. 

D the speed at which the planet spins on its axis. 

48. The alkali metals are in Group 1 in the Periodic Table. The atoms of 

alkali metals have one electron in their outermost level. Which of the 

following statements about alkali metals is true? 

F Alkali metals are generally found in their uncombined form. 

G Alkali metals have low densities. 

H Alkali metals should be stored underwater. 

J Alkali metals are unreactive. 


82 





49. Based on the Periodic Table segment below, which pair of elements 

would most likely have a similar arrangement of outer electrons? 

13 

5 

B 

10.81 

13 

Al 

26.98 

A boron and aluminum 

B helium and fluorine 

C carbon and nitrogen 

D chlorine and oxygen 

14 

6 

C 

12.01 

14 

Si 

28.09 

15 

7 

N 

14.01 

15 

P 

30.97 

16 

8 

O 

16.00 

16 

S 

32.06 

17 

9 

F 

19.00 

17 

Cl 

35.45 

18 

2 

He 

4.00 

10 

Ne 

20.18 

18 

Ar 

39.95 

50. In a laboratory investigation on changes in states of matter, Melissa 

observes that the melting point of water is 0° Celsius and that the 

freezing point of water is 0° Celsius. What can Melissa conclude from 

this observation? 

F Both melting and freezing are exothermic reactions. 

G Water boils at 0° Celsius. 

H Melting and freezing can occur at the same temperature. 

J She made an error in her measurements. 


83 





51. When a chemical reaction occurs, atoms are never 

A ionized. 

B rearranged. 

C destroyed. 

D vaporized. 

52. How many atoms are represented in the formula CaCO 3 ? 

F 3 

G 4 

H 5 

J 6 


84 





53. The solubility of the material used to construct the graph below is 

88 g/100 g H 2 O at 20°C. What is the solubility of the substance at 60°C? 

Grams of solute 

per 100 g H2O 240 

200 

160 

120 

80 

40 

Temperature Vs. Solubility 

0 

0 20 40 60 80 

100 

Temperature (˚C) 

A 88 g/100 g H 2 O 

B 100 g/100 g H 2 O 

C 122 g/100 g H 2 O 

D 264 g/100 g H 2 O 

54. What do you end up with if you cut a magnet in half? 

F one north-pole piece and one south-pole piece 

G two unmagnetized pieces of metal 

H two pieces each with a north pole and a south pole 

J two north-pole pieces 


85 





55. Which of these changes would increase the strength of an 

electromagnet? 

A use a plastic core instead of a metal core 

B add more coils of wire 

C make the wire coils bigger 

D alternate the direction of current 

56. What do scientist think is the cause of Earth’s magnetic field? 

F rotation of the solid inner core of the planet 

G charged particles flowing in the liquid outer core 

H iron in the rocks of the mesosphere 

J induction caused by the solar wind 


86 





57. Which of these drinks is the strongest acid? 

A milk 

B tap water 

C tea 

D orange juice 

58. What is one of the properties of a strong base? 

F sour taste 

G reacts with metal to produce hydrogen gas 

H dissolves glass 

J has a slippery feel 


87 





59. Which of the following elements is the least reactive? 

A nitrogen 

B gold 

C argon 

D chlorine 

60. Which of these materials is a chemical compound? 

F lemonade 

G baking soda 

H brass 

J paper 


88 





61. In the water cycle, as illustrated below, at what point does water gain 

energy? 

A evaporation 

B condensation 

C precipitation 

D none of the above 

62. A certain substance has a definite shape and volume, and its particles 

do not move fast enough to overcome the attraction between them. 

What do these properties indicate about the state of the substance? 

F It is a solid. 

G It is a liquid. 

H It is a gas. 

J It is a plasma. 


89 





63. During field investigations of undisturbed rock layers, scientists can 

assume that the relative age of a rock layer is probably 

A determined by using radioactive decay. 

B more than the age of the fossils it contains. 

C less than the age of the fossils it contains. 

D less than the rock layer below it. 

64. Which of these is an example of technology? 

F designing a process for making biofuel 

G writing a novel 

H climbing a mountain 

J burning wood in a campfire 


90 





65. The figure below shows a model of a boron atom. Which model of the 

atom is shown? 

A Dalton’s model 

B the plum-pudding model 

C Bohr’s model 

D the electron-cloud model 

66. Which of the following actions would not help maintain biodiversity? 

F protecting individual species 

G protecting forests and wetlands 

H preventing industrial wastes from being dumped in the ocean 

J increasing consumption of natural resources 


91 





67. How do branching diagrams help scientists analyze fossils and living 

organisms? 

A Branching diagrams are used to identify, and show relationships 

between, organisms. 

B Branching diagrams are used to identify, and show all of the 

characteristics of, organisms. 

C Branching diagrams are used to identify and show all organisms. 

D Branching diagrams are used to identify organisms and show their ages. 

68. Which of the following is true about flammability? 

F Flammability is a physical property. 

G Flammability is a chemical property. 

H Flammability is a not a property. 

J Flammability is a not a characteristic property. 


92 





69. In the figure below, the black circles represent neutrons. What is the 

atomic number of the atom shown? 

A 3 

B 4 

C 7 

D 11 

70. An element is shiny, brittle, and a poor conductor of electricity. Which 

of the following is the best classification for the element? 

F metal 

G nonmetal 

H metalloid 

J transition metal 


93 





71. Which animals on a branching diagram are the most closely related? 

A the two at the top of the diagram 

B the two at the bottom of the diagram 

C any two animals next to each other on the diagram 

D the animals on each end on the diagram 

72. A Siberian tiger and a common house cat do not belong to the same 

F order. 

G species. 

H class. 

J family. 


94 





73. Based on this chart, what can you conclude about transition metals? 

Element Density 

(g/cm3 Melting Appearance 

) point (°C) 

Chromium 7.15 1907 shiny, silver-colored, hard 

Lithium 0.534 180.5 shiny, gray, soft 

Gold 19.3 1064.18 shiny, yellow, hard 

Potassium 0.89 63.38 shiny, gray, soft 

Sodium 0.97 97.72 shiny, silver-colored, soft 

A Transition metals have a greater density than nonmetals. 

B Transition metals have a lower density than alkaline earth metals. 

C Transition metals have a higher melting point than alkali metals. 

D Transition metals are yellow colored. 

74. What is the source of the magnetic field of a solenoid? 

F protons moving inside a bar magnet 

G electrons moving in a coil of wire 

H the interaction of a current and Earth’s magnetic field 

J a moving magnet 


95 





75. Biological classification schemes change 

A as new evidence and more kinds of organisms are discovered. 

B about every 100 years. 

C when scientists disagree. 

D only once. 

76. Which of these is the best description of what type of scientists work 

with engineers to develop new technologies? 

F physicists and chemists 

G technology specialists 

H scientists from any specialty 

J mathematicians 

77. Why does Jupiter’s gravity have a tiny effect on Earth even though it is 

the largest planet? 

A Planets do not affect one another through gravity. 

B The sun’s gravitational force is so strong that it hides Jupiter’s. 

C Earth is not large enough to be affected by Jupiter. 

D Jupiter has a small gravitational pull because it is very distant. 


96 




Practice Test B 

1. Based on the pie chart of components of seawater below which of the 

following is not a valid conclusion? 

Other = 0.7% 

Potassium = 1.1% 

Calcium = 1.2% 

Chlorine = 55.0% 

Sulfur = 3.7% Magnesium = 7.7% 

Sodium = 30.6% 

A Because there is a greater amount of chlorine in the sample than sodium, 

there must be additional sources of chlorine in the environment besides 

the compound sodium chloride. 

B The dissolved sodium chloride found in the sample is a different 

compound from the sodium chloride used in cooking. 

C Magnesium salts are more than twice as common as sulfur salts. 

D The ocean tastes salty because the most abundant dissolved solid is 

sodium chloride. 

2. Which one of the following does not represent a mixture? 

F grape juice 

G water from a freshwater lake 

H a popsicle 

J distilled water 


97 






is called 

A a liquid. 


C homogeneous. 

D heterogeneous. 

4. Reactivity is the ability of substances to combine and form new 

substances. What substance listed below exhibits chemical reactivity 

when combined with vinegar? 

F water 

G baking soda 

H sugar 

J cooking oil 


98 





5. This drawing shows the fossils found in rock layers at three different 

sites of a field investigation. Layer A contains an index fossil of a type 

of trilobite called Phacops. Which of the following is a valid conclusion 

about rocks in layer A at all three sites? 

A They were all formed at different times. 

B They are all different ages. 

C They are all about the same age. 

D They were all formed catastrophically. 

6. In what way is a successful experiment never the final step in a 

scientific investigation? 

F The results may later be proven wrong. 

G Scientists have to keep investigating so that they have work to do. 

H The data from an experiment lead to new questions and further 

investigation. 

J The experiment is not complete until a new theory is proposed. 


99 





7. Which of the following is not part of Darwin’s theory of natural 

selection? 

A Individuals in a population are different from one another. Some of those 

differences are genetic traits. 

B More offspring are born than will live to become adults. 

C Individuals that have favorable traits are more likely to survive and 

reproduce. 

D All organisms within a species have the same number of offspring. 

8. Which process causes substances to react to form one or more 

new substances? 

F chemical change 

G physical change 

H evaporation 

J freezing 


100 





9. Examine the graph below. Which of the following is a reasonable 

conclusion drawn from the data in the graph? 

Beak size (mm) 

Average Beak Size in Galápagos Finches 

10.0 

9.0 

Dry 

year 

Dry 

year 

Dry 

year 

Wet year 

1978 1980 

Year 

1982 1984 

A Beak size has steadily increased over the years. 

B The wetter the year, the shorter the beak size of the Galápagos finch. 

C Beak size has remained the same, while climate has changed over time. 

D The longer the beak size of the Galápagos finch, the fewer seeds there are. 

10. Which of these is the appropriate SI unit for measuring a chemical to 

place in a test tube during a lab experiment? 

F ounce 

G gram 

H kilogram 

J pound 


101 





11. The Law of Universal Gravitation states that the movements of the 

planets around the sun depend on 

A the composition of the planet. 

B the planet’s mass and distance from the sun. 

C the number of moons a planet has. 

D the speed at which the planet spins on its axis. 

12. The ability of substances to combine and form new substances is called 

F solubility. 

G physical reactivity. 

H chemical reactivity. 

J malleability. 


102 





13. David set up an experiment to determine how tall some house plants 

can grow. He tested the hypothesis that house plants grow taller when 

they are exposed to more hours of light. His experimental conditions 

are shown in the table below. The last column in the table shows how 

much the plants grew. Which factor is the variable? 

Group 

Experiment to Test How Tall Plants Grow 

Factors Results 

Kind of Amount Amount Light Growth 

Plant of Soil of Water exposure (cm) 

(ounces) (cups per (hours per 

week) day) 

1 (Control) House 

plant 

2 (Experimental) House 

plant 


plant 


plant 

A kind of plant 

B amount of water 

C light exposure 

D growth 

16 25 0 -8 

16 25 5 2 

16 25 10 15 

16 25 15 20 

14. Which of these would not be an example of technology? 

F using electric currents to study magnetism 

G detecting an avalanche by hearing it from a distance 

H monitoring a tornado with tiny radio transmitters 

J recording changes in the rain forest by comparing satellite photos 


103 





15. What does a dichotomous key use to help a scientist identify 

organisms? 

A a series of statements 

B a graph of typical data 

C a series of photographs 

D a chart with circles and arrows 

16. Which of the following is not a prey adaptation? 

F camouflage 

G chemical defenses 

H parasitism 

J warning coloration 


104 





17. While cutting through the side of a mountain to build a highway, 

workers expose several layers of rock, as shown in the diagram below. 

Fossils of whale bones, shark teeth, and sand dollars are found in the 

rocks that form Layer 4. Fossils of rodents, toads, and lizards are found 

in Layer 2. These discoveries support which of the conclusions below? 

Layer 1 

Layer 2 

Layer 3 

Layer 4 

Layer 5 

A When Layer 4 formed, the mountain was near a large lake. 

B When Layer 4 formed, whales, sharks, and sand dollars lived in the 

mountains. 

C When Layer 4 formed, the area where the fossils were found was covered 

by an ocean. 

D When Layer 4 formed, whales, sharks, lizards, toads, and rodents were in 

the same food web. 

18. The process by which organisms that are better adapted to their 

environment survive and reproduce more successfully than less well 

adapted organisms do is called 

F natural selection. 

G fossilization. 

H extinction. 

J selective breeding. 


105 





19. Heredity, experience, and adaptation to the environment 

A hinder a species from adapting further. 

B negatively affects the abiotic factors in an environment. 

C prohibits an organism from changing. 

D determines an organism’s behavior. 

20. Smog can be considered a colloid when it is composed of 

F particles too small to settle out. 

G a cloudy suspension. 

H a chemical compound. 

J a pure element. 


106 





21. Organisms have changed over time. Scientists have proven this fact by 

A examining and comparing fossil evidence. 

B discovering all the organisms that have ever lived on Earth. 

C finding that organisms of the past are identical to those living today. 

D proving that there are more organisms with bones than without. 

22. When a strong base is dissolved in water, it produces a solution 

containing a high concentration of 

F hydrogen ions. 

G hydronium ions. 

H hydroxide ions. 

J ammonium ions. 


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23. An atom has 5 protons, 6 neutrons, and 5 electrons. What is the atom’s 

mass number? 

A 5 

B 10 

C 11 

D 16 

24. Which of the following is true about Bohr’s model of the atom? 

F The electrons are located throughout the positively charged material. 

G The electrons travel in definite paths around a small, positively charged 

nucleus. 

H There are regions around the nucleus where electrons are likely to be 

found. 

J The center of the atom is positively charged and dense, and electrons 

travel around it but in no exact arrangement. 


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25. Based on the Periodic Table segment below, which pair of elements 

would most likely have a similar arrangement of outer electrons? 

A neon and argon 

13 

5 

B 

10.81 

13 

Al 

26.98 

B helium and fluorine 

C oxygen and nitrogen 

14 

6 

C 

12.01 

14 

Si 

28.09 

D phosphorus and silicon 

15 

7 

N 

14.01 

15 

P 

30.97 

16 

8 

O 

16.00 

16 

S 

32.06 

17 

9 

F 

19.00 

17 

Cl 

35.45 

18 

2 

He 

4.00 

10 

Ne 

20.18 

18 

Ar 

39.95 

26. What do scientists use branching diagrams for? 

F to help classify animals 

G to determine which animals can breed 

H to show how humans are related to plants 

J to show the family tree of a species 


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27. How does Earth’s magnetic field resemble that of an electromagnet? 

A Earth’s field is caused by the alignment of magnetic domains. 

B Electric current flows in coils inside Earth. 

C Both fields are caused by the motion of charged particles. 

D Gravity affects the shape of both fields. 

28. The fact that all organisms have DNA as their genetic material is 

evidence that 

F all organisms undergo natural selection. 

G all organisms may have descended from a common ancestor. 

H selective breeding takes place every day. 

J genetic resistance rarely occurs. 


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29. Which conclusion can you make from the diagram below? 

A All mammals descended from aquatic ancestors. 

B Whales are larger than other mammals. 

C Pigs and whale share a common ancestor. 

D Camels and llamas are ancestors of the other mammals on the list. 

30. Which of the following is true about the tree of life? 

F The tree of life includes only fossils. 

G The tree of life includes all know organisms. 

H The tree of life is a complete record of life on Earth. 

J The tree of life is the same as the fossil record. 


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31. Which of the following is not a physical property of matter? 

A state 

B color 

C luster 

D pH 

32. Which group of the Periodic Table includes the most reactive 

nonmetals? 

F group 2 

G group 9 

H group 17 

J group 18 


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33. In the picture below, the circles in the jars represent atoms of an 

element. The substance in Jar 2 is in which physical state? 

A gas 

B liquid 

C solid 

D energetic 

34. Which statement applies to the transition metals? 

F They are very reactive compared to other metals. 

G They display a very wide range of properties. 

H They tend to gain electrons easily. 

J They have similar properties to one another. 


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35. How does the fossil record help scientists learn how species have 

changed over time? 

A Scientists use the fossil record to determine how fossils are formed. 

B Scientists use the fossil record to examine the DNA of extinct organisms. 

C Scientists use the fossil record to look for relationships between extinct 

and living organisms. 

D Scientists use the fossil record to determine the age of Earth. 

36. Carbon-14 can be used to determine the age of objects up to 

F 10,000 years old. 

G 50,000 years old. 

H 1,000,000 years old. 

J 50,000,000 years old. 


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37. Assuming that you can see all of the particles in this nucleus, what is its 

atomic number? 

A 6 

B 8 

C 12 

D 14 

38. Why do parts of Earth’s history lack a fossil record? 

F Only organisms that lived on land can form fossils. 

G Fossils of extinct organisms cannot be found. 

H Only animals form fossils so no fossil record of plants is known. 

J Fossils are rare because specific conditions are necessary for fossils 

to form. 


115 





39. Which of the following is not evidence that supports Darwin’s theory of 

Natural Selection? 

A gaps in the fossil record 

B historical sequence of life found in the fossil record 

C fossils of more primitive life forms found in lower sedimentary layers 

D vestigial structures 

40. In what part of the atom is most of its mass located? 

F the nucleus 

G the electron cloud 

H the protons 

J the electron path 


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41. Which of the following changes would not affect the strength of the 


A decreasing the current 

N 

Current 

B placing an iron rod inside the solenoid 

Current 

C placing a wooden dowel inside the solenoid 

D increasing the number of wire coils 

42. Which of these elements has seven valence electrons? 

F helium 

G argon 

H chlorine 

J oxygen 


117 

S 





43. A device that uses electromagnetic induction to convert kinetic energy 

into electrical energy is a 

A transformer. 

B generator. 

C motor. 

D solenoid. 

44. An insecticide kills a few insects, but a few survive. Because of natural 

selection, which of the following is most likely to happen? 

F Eventually the rest of the insects will die off. 

G The survivors will reproduce, and the replacement population will be 

resistant to the insecticide. 

H The survivors will reproduce, but the offspring will be killed by another 

application of insecticide. 

J The survivors will reproduce but will be deformed. 


118 





45. The table below shows data from a laboratory experiment in which 

Anne measured the temperatures of the following substances: ice, ice 

water, water at room temperature, and boiling water. Which of the 

following is a valid conclusion based on this experiment? 

Temperature of Substances 

Substance Temperature 

Ice −2 o C 

Ice water 0 o C 

Water 27 o C 

Boiling water 100 o C 

A For water, phase changes occur at 0° C and 100° C. 

B Molecules in ice have a greater attraction for one another than in liquid 

water. 

C Water does not absorb energy at 0°C. 

D Thermal energy is not related to temperature. 

46. According to the Law of Conservation of Mass 

F change has nothing to do with saving or losing mass during a chemical or 

physical change. 

G amount of matter present after a change is less because matter has been 

saved. 

H amount of matter present before a change is the same as the amount 

present after a change. 

J amount of matter present before a change is less than the amount 

present after a change. 


119 





47. Which one of the following waves requires a medium? 

A electromagnetic waves 

B mechanical waves 

C light waves 

D X rays 

48. Which of these is the earliest known hominid? 

F Cro-Magnon 

G Australopithecine 

H Homo habilis 

J Neanderthal 


120 





49. Look at the diagram below. What kind of substance should appear in 

the blank space under pure substance? 

Matter 

Pure substance Mixture 

Element Heterogeneous mixture 

A colloid 

B compound 

C molecule 

D atom 

50. Until the 1700s, scientists classified organisms into only two kingdoms. 

Today’s scientific classification system has four kingdoms. Why have 

scientists added more kingdoms? 

F The previous theory of classification did not account for the Latin names 

of organisms. 

G Scientists thought there were too many organisms to classify into only 

two kingdoms. 

H Scientists found that some living things did not fit into the plant group or 

the animal group. 

J Scientists found too many similarities between organisms in different 

kingdoms. 


121 





51. Which of the following traits found in birds is not an adaptation for 

flight? 

A rigid skeleton 

B sharp beak 

C light skeleton 

D keel bone 

52. Aluminum-27 has 13 protons. What is the total mass of its neutrons? 

F 13 amu 

G 14 amu 

H 27 amu 

J 40 amu 


122 





53. You are doing a lab experiment that involves recording the time it 

takes for a solution to change color after mixing. This table shows 

your measurements. Time 3 differs significantly from the other 

measurements. How should you handle that data point? 

Test 1 2 3 4 

Time (sec) 28 31 48 30 

A Erase it from your records because it is obviously wrong. 

B Avoid writing in your notebook in the first place. 

C Change the number so it matches the other times. 

D Record the data and try to figure out why it was different. 

54. Iodine is in Group 17 of the Periodic Table. During chemical changes, it 

forms an ion whose charge is 

F –1 

G –2 

H +1 

J +2 


123 





55. Which of the following is a learned behavior? 

A a human walking upright 

B a mother killdeer pretending to have a broken wing 

C a crane performing a courtship dance to attract a mate 

D a chimpanzee using a stick to get food from a hard-to-reach area 

56. The function of the generator at a hydroelectric plant is to convert 

F mechanical energy into electrical energy. 

G kinetic energy into magnetic energy. 

H thermal energy into magnetic energy. 

J electrical energy into mechanical energy. 


124 





57. Look at the model of an oxygen atom. How would this atom form 

an ion? 

A gain one electron 

B gain two electrons 

C gain four electrons 

D lose six electrons 

58. Which of the following will induce an electric current in a wire? 

F moving a magnet into a coil of wire 

G moving a wire between the poles of a magnet 

H turning a loop of wire between the poles of a magnet 

J all of the above 

Oxygen 


125 





59. Which of the following assumptions is not part of the kinetic theory? 

A All matter is made up of tiny, invisible particles. 

B The particles are always moving. 

C Particles move faster at higher temperatures. 

D Particles are smaller at lower pressure. 

60. Diamond and graphite are very different, yet both are naturally 

occurring forms of the element 

F carbon. 

G silicon. 

H boron. 

J lead. 


126 





61. The transformer shown below has twice as many coils on the right 

side as on the left side. How will its output voltage compare to its 

input voltage? 

Primary coil Secondary coil 

A output voltage is half the input voltage 

B output voltage is equal to the input voltage 

C output voltage is double the input voltage 

D output voltage is four times the input voltage 

62. A scientist has a hypothesis that a stream is acidic because it contains 

sulfuric acid from acid rain. An experiment shows that there is nitric 

acid, but no sulfuric acid in the stream. The hypothesis was 

F not valuable because there was no sulfuric acid. 

G not valuable because the acids were not analyzed correctly. 

H valuable because it led to an experiment that showed what acid is in the 

stream. 

J valuable because there may be sulfuric acid in the next stream that is 

tested. 


127 





63. Potassium iodide is soluble in water and has a melting point of 680°C. 

The atoms or ions in this compound are held together by 

A carbon-chain molecules. 

B electrons shared between the atoms. 

C the bonds between ions of opposite charges. 

D attraction between nuclei of potassium and iodine atoms. 

64. The reason mass and weight are the same everywhere on Earth’s 

surface is because 

F mass and weight are the same thing. 

G mass and weight are measured the same way. 

H the gravitational force is the same. 

J mass is the same as weight throughout the universe. 


128 





65. Students using the dichotomous key below notice that one tree has thin 

1.2 cm needles that occur in clusters. Which of the following inferences 

can be made? 

A Dichotomous Key to Common Trees of the Northern United States 

1. a. Leaves are thin and needlelike (coniferous) 

b. Leaves are broad and fanlike (deciduous) 

2. a. Needles are over 2.5 cm long and are clustered 

b. Needles are 1.25 cm long or less. 

3. a. Needles occur in clusters of 3 

b. Needles occur in clusters of 5 

A The plant is deciduous. 

B The plant is a Pinus rigida. 

C The plant is an Eastern white pine. 

Go to 2 

Go to 6 

Go to 3. 

Go to 4. 

Pitch pine (Pinus rigida) 

Eastern white pine (Pinus strobus) 

D The plant cannot be identified from the information provided. 

66. Balancing a chemical equation so that the same number of atoms of 

each element is found in both the reactants and the products is an 

application of 

F activation energy. 

G conservation of energy. 

H conservation of mass. 

J a double-displacement reaction. 


129 





67. Which of the following is not a characteristic of metals? 

A shiny 

B malleable 

C brittle 

D ductile 

68. Why does a falling object move toward Earth instead of Earth moving 

toward the object? 

F The force of gravity pulls small objects to larger objects. 

G Gravity acts on objects only when they are close to the surface of Earth. 

H Earth does move toward the object, but because of the difference in mass, 

that motion cannot be detected. 

J Inertia keeps Earth from moving. 


130 





69. Look at the solenoids and electromagnets shown below. Identify which 

of them has the weakest magnetic field. 

A 

B 

C 

D 

Current — 2 A 




70. Which of the following is not a compound? 

F carbon dioxide 

G water 

H table salt 

J hydrogen 


131 





71. What type of elements are used as semiconductors for electronics 

applications? 

A transition metals 

B metalloids 

C rare earth metals 

D group 4 metals 

72. The elements in a compound 

F join in a specific ratio according to their masses. 

G combine by reacting with one another. 

H can be separated by chemical changes. 

J All of the above 


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73. What is the correct formula for sodium sulfide? 

A NaS 

B Na 2 S 

C NaS 2 

D SoS 

74. Which of the following does not use the relationship between electricity 

and magnetism in its normal operation? 

F generator 

G motor 

H transformer 

J light bulb 


133 





75. Calcium is an alkaline earth metal. What is the ratio of calcium atoms 

to oxygen atoms in calcium oxide? 

A 1:1 

B 2:1 

C 1:2 

D 1:3 

76. Which adaptation might give an advantage to an animal living in a 

hot desert? 

F brightly coloration 

G nocturnal habits 

H large feet 

J small teeth 

77. What classification applies to all of the elements on the list below? 

A transition metal 

B alkaline earth metal 

C alkali metal 

D metalloid 


134

Holt Science and Technology Grade 8 Tennessee Comprehensive ...

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