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PREFACE
The Synergy for Success in Science Series aims to enable students acquire in-depth
knowledge and understanding of science concepts relevant to daily life, society, and the
environment.
This series aims to develop students into lifelong learners having deep appreciation of
scientific knowledge and processes, and equipped with scientific attitudes, skills, and values.
Each book in the series uses concrete examples and matches them with colorful visuals
and language that is suited to the level of the students to whom the book is intended. This
makes learning experience relevant, accessible, and meaningful to students regardless of
their background and language skills.
This series makes science learning easier with the help of the following features:
Key Concept Important key words and concepts are defined, compared, and
differentiated. This facilitates easy understanding of science
concepts.
Know More This concept-related information enriches students knowledge and
reinforces their understanding of science concepts, hence appreciate
their applications.
Let’s Review These open-ended questions reinforce students understanding and
mastery of science concepts in
each lesson.
Let’s Do ThisThese are simple classroom exercises that enable students to explore
and apply science concepts in real-life experiences.
Chapter SummaryThis serves as a review guide for students.
Key Ideas summarizes important concepts at the end
of each chapter.
Concept Map is a visual summary of the concepts presented in the
chapter.
Chapter Test These multiple choice and structured questions enable students
evaluate their knowledge, understanding, skills, and mastery of the
concepts on their own.
Enrichment
This contains suggested activities that students can do in relation to
the topic in each chapter.
Making ConnectionsThis present practical application/s of the science concept
discussed in the chapter.
iii
iii
Table of Contents
Preface
unit 1
Earth and Space
Chapter 1
The Internal Structure of Earth
Layers of Earth
Theories of Diastrophism
Chapter Summary
Chapter Test
Making Connections
3
9
11
13
16
Plate Tectonics
Continental Drift Theory The Theory of Plate Tectonics
Chapter Summary
Chapter Test
Making Connections
18
21
25
27
29
1.1
1.2
Chapter 2
2.1
2.2
unit 2
Force, Motion, and Energy
Chapter 3
Electromagnetic Spectrum
Electromagnetic Waves
Electromagnetic Spectrum
Chapter Summary
Chapter Test
Making Connections
33
37
44
46
48
Light
Mirrors
Lenses
Optical Instruments Chapter Summary
Chapter Test
Making Connections
50
63
74
78
80
83
3.1
3.2
Chapter 4
4.1
4.2
4.3
iv
iii
Chapter 5
Electricity and Magnetism
5.1
Electromagnetic Induction 86
5.2
Applications of Electromagnetic Induction
94
Chapter Summary
100
Chapter Test
102
Making Connections
105
unit 3
Living Things and their Environment
Chapter 6
Coordinated Functions of the Endocrine, Reproductive, and
Nervous Systems
6.1
The Endocrine System 109
6.2
The Reproductive System 116
6.3
The Nervous System 130
Chapter 7
Chapter Summary
141
Chapter Test
143
Making Connections
145
Heredity: Inheritance and Variation
7.1
Nucleic Acids: DNA and RNA 148
7.2
Central Dogma of Molecular Biology 155
7.3
Mutations 166
Chapter 8
Chapter Summary
175
Chapter Test
177
Making Connections
179
Evolution
8.1
The Theory of Evolution 182
8.2
Evidence of Evolution 192
Chapter Summary
200
Chapter Test
202
Making Connections
205
v
Chapter 9
9.1
9.2
unit 4
Chapter 10
10.1
10.2
Chapter 11
11.1
11.2
11.3
11.4
Chapter 12
12.1
12.2
Ecology
Biodiversity and Ecosystem Stability
Population Ecology
Chapter Summary
Chapter Test
Making Connections
The Science of Matter
Gas Laws
Basic Properties of Gases
Gas Laws
Chapter Summary
Chapter Test
Making Connections
233
237
256
259
262
Biomolecules
Biomolecules
Carbohydrates
Lipids Proteins Chapter Summary
Chapter Test
Making Connections
264
267
272
278
285
287
290
Chemical Reactions
Chemical Equations
Patterns of Chemical Reactivity Chapter Summary
Chapter Test
Making Connections
292
298
305
307
309
Glossary
Index
vi
208
217
224
226
229
311
321
Unit 1
Earth and Space
E
arthquakes occur when the stress under the plates
is suddenly released. Last 2013, a 7.2–magnitude
earthquake hit the province of Bohol in the
Philippines. The earthquake killed many people and
destroyed houses, establishments, and even Loboc church,
one of the old churches in the Philippines.
In this unit, the internal structure of Earth and their
functions are discussed. The theories and the factors that
explain the plate movements are also included in this unit.
Chapter 1
The Internal
Structure of Earth
Geologists describe Earth as an astronomical body
composed of layers of rocks and minerals. Each layer
has its own function that helps maintain the condition of
Earth. The outer core, for example, helps in maintaining
Earth’s magnetic field.
In this chapter, the layers of Earth and how they interact
with one another are discussed.
LEARNING GOALS
• Describe the internal structure of Earth.
• Determine the functions of each layer of Earth.
• Describe and analyze the different theories of diastrophism.
2
Earth and Space
1.1 Layers of Earth
!
Know More
Earth is divided into three layers namely, the crust, the
mantle and the core. Each layer has its own composition,
properties and characteristics.
Ocean floors are also
known as sima. The
word sima is from the
elements silicate and
magnesium. These two
are the main components
that make up the ocean
floors.
ocean
crust
mantle
core
Figure 1.1 Earth has three major layers. Each layer is divided into sublayers.
Crust
The crust is the outermost and the thinnest layer
of Earth. It is made up of igneous, sedimentary,
and metamorphic rocks.
The crust is broken up into plates. Plates are composed of
great variety rocks that are made up of silicon, aluminum,
minerals, and ores.
The crust has two types, namely, continental crust and
oceanic crust.
oceanic
crust
continental
crust
upper mantle
Figure 1.2 The thickness of Earth's crust is approximately 18 miles
The Internal Structure of Earth
3
Continental crust
The continental crust covers almost 40 percent of Earth
and makes up the continents. It is made up of sials, which
are rocks made of granite rich in aluminum silicate. It has
g
an approximate density of 2.6
.
cm 3
Oceanic crust
The oceanic crust is found beneath the ocean floor. It is
formed from the lava that seeped up from mid-ocean
ridges. These undersea mountain ranges have openings
where the magma comes out. Cooled by the seawater,
the lava covers the sea floor, thus, forming a new oceanic
crust.
Lava is the magma that seeped up from volcanoes
or mid‑ocean ridges.
Magma is a mixture of hot liquid base, mineral
crystals, semi-molten rocks, and dissolved gases.
It is found beneath the surface of Earth.
The oceanic crust is thinner and denser
than the continental

g 

crust. It has an approximate density
. On the
densityof= 3

cm 3 
average, it is about 4 miles thick. It is made up of darkcolored igneous rocks known as basalt rocks.
A basalt rock is an igneous rock that is made up of
silicon, oxygen, and magnesium.
Mantle
The mantle is the thickest layer of Earth. It consists
of hot, dense silicate rock shell which is made up
of silicon, oxygen, and other elements.
The mantle lies between the core and the crust. It is
divided into the upper and lower mantle. The upper
mantle includes the lithosphere and the asthenosphere.
4
Earth and Space
The lower mantle is located between the upper mantle
and the core.
!
Know More
upper mantle ( » 477 miles)
lower mantle ( » 1349 miles)
The boundary between
the crust and mantle
is called Mohorovicic
discontinuity or Moho. It
was named after Andrija
Mohorovičić (1857–1936),
a Croatian metreologist
and geophysicist who
discovered Moho.
Figure 1.3 The mantle is about 1800 miles thick.
Upper mantle
The upper mantle is composed of variety of rocks. One of
them is peridotite, which is made up of minerals, olivine,
and pyroxene. This layer includes all layers below the
crust down to a depth of about 447 miles.
Lithosphere
Lithosphere, the upper part of the mantle, is about 60 miles
thick. Like crust, it is made up of variety of rocks but it is
cooler and more rigid.
Asthenosphere
Asthenosphere is located below the lithosphere. It is softer,
hotter, and more fluid than the lithosphere. Asthenosphere
carries broken large pieces of lithosphere on it. Its flow is
part of mantle convection, which is the heat transfer from
material to another material that occurs in the mantle.
The Internal Structure of Earth
5
!
Know More
The name pyroxene
is derived from the
Greek pyro meaning
“fire” and xenos meaning
“stranger” and was given
by Rene Just Haüy.
oceanic crust
lithosphere
Continental Crust upper most Layer
of the mantle
continental crust
asthenosphere
Figure 1.4 The asthenosphere is thicker than the lithosphere.
Lower Mantle
The lower mantle is the layer found between the upper
mantle and the core. It is made up of iron, magnesium, and
silicate compounds. It is denser and hotter than the upper
mantle. It is about 1349 miles depth and plays a major role
in controlling the thermal evolution of the planet.
Core
The core is the deepest and the hottest layer of
Earth found beneath the mantle. It is made up
iron and nickel.
crust
mantle
outer core
1 400 miles thick
liquid iron and
nickel
inner
core
6
Earth and Space
The core is made up of two layers, namely, the outer core
and the inner core. Some scientists believe that the metals
in the core are in constant motion and that the inner core
rotates faster.
Outer Core
The outer core is about 1400 miles thick. With a temperature
ranging from 4000 °C to 5000 °C, the layer is so hot that the
iron and nickel metals are liquid.
The outer core is very important to Earth as it creates the
magnetic field. This magnetic field goes way out into the
space and makes a protective barrier around Earth. It
shields the planet from the Sun’s damaging solar wind.
magnetic
North Pole
geographic
North Pole
liquid inner
core
solid
inner core
geographic
South Pole
magnetic
South Pole
Figure 1.5 The convection current in the outer core
generates the magnetic field.
Inner Core
The inner core is the innermost layer of Earth with a radius
of about 759 miles. It has a temperature ranging from
5000 °C to 7000 °C. It is under immense pressure that the
inner core is still solid even though it is hot.
!
Know More
liquid core
inner core
mantle
Figure 1.6 The inner core represents 1.7% of the Earth's mass.
In 1936, Danish seismologist
Inge Lehmann (1888–1993)
discovered the inner core
and the outer core of
Earth. She observed that
seismic waves created by
earthquakes on the surface
of Earth would bounce off
the two cores differently.
The Internal Structure of Earth
7
Let’s Review
1 What are the layers of mantle?
2 Differentiate between the oceanic crust and the
continental crust.
Let’s Do This!
Purpose
Build a clay model of Earth
What You Need
red, orange, yellow, and blue clays
rolling pin
ruler
knife or cutter
marble
What You Need to Do
1 Make a red clay ball that has a diameter of 30 mm. Set it aside.
2 Using the rolling pin, flatten the orange, yellow, and blue clays. The
thickness of the orange clay should be at least 50 mm; the yellow
clay should be at least 5 mm thick; and the blue clay should be 11
mm thick.
3 Cover the red clay with the orange clay. Make sure that the red clay
ball is completely covered with the orange clay ball.
4 Cover the clay ball with the yellow one and then the blue one. Make
sure the clay ball is completely covered before covering it with
another layer of clay.
5 Cut the clay ball in half using a knife or cutter. Then insert the
marble at the middle of the red clay ball.
Guide Questions
1 Roll the marble while it is in the middle of the clay ball. How does it
affect the other layers?
2 If you move one of the layers in the clay ball, will it affect the other
layers? How is this similar to the layers of Earth?
8
Earth and Space
1.2 Theories of Diastrophism
!
Know More
Diastrophism (or tectonism) refers to the deformation of
Earth's crust which leads to the formation of different
landforms and other features.
The deformations are caused by Earth's movements,
namely, uplift, subsidence, and thrust. Uplift refers to the
movement in which the crust rises, while the subsidence
is the sinking of the crust. Thrust refers to the horizontal
movement of the crust. These movements are supported
and explained by the theories of diastrophism—the theory
of isostasy, the contraction theory, the convection theory,
and the expansion theory. The descriptions of each theory
are listed on the table below. Continental drift theory also
is a theory of diastrophism. It will be discussed in chapter 2.
American geologist
Clarence Edward Dutton
(1841–1912) coined the
term ‘isostasy’ in 1889.
Theory
Theory of Isostasy
Description
The term isostasy comes from the
Greek ísos which means "equal," and
stásis which means "standstill." The
theory refers to the balance of the
crust such that it floats and elevates
on a denser material based on its
density and thickness.
Contraction Theory The contraction theory states
that Earth is shrinking through
geological time. As it shrinks, the
bigger chunks and blocks of crust
are pushed downward; and they
eventually sink. The lighter and the
smaller chunks are then compressed
and pushed upward.
Convection Theory The convection current theory states
that the crusts and rocks are pushed
by convection currents. As the rocks
are pushed, they tend to move
upward. This movement causes the
folding and deformation in the crust.
Expansion Theory
The expansion theory states that
Earth is expanding in size and mass
and that the distance of the continents
from one another is increasing as
well.
The Internal Structure of Earth
9
Let’s Review
Enumerate and explain the theories of diastrophism.
Let’s Do This!
Purpose
Demonstrate how land erosion affects the crust balance in water
What You Need
2 pieces of Styrofoam
scissors
glue
a basin of water
1 cup soil
What You Need to Do
Cut an 8" × 8" piece and a 4" × 4" piece of Styrofoam.
Glue the 4" × 4" piece on the top of the 8" × 8" piece.
Place the glued pieces on the basin filled with water.
Put 2 spoonfuls of soil on the 4" × 4" piece. Observe how the Styrofoams
balances on the water.
5 Remove the glued pieces from the basin and move the soil to the
remaining part of the 8" × 8" piece. Observe how the Styrofoam floats
in the water.
1
2
3
4
Guide Questions
1 How did the Styrofoam float when the soil was on the top of the
4" × 4" piece?
2 How did the weight of the soil affect the balance of the Styrofoam?
10
Earth and Space
Chap ter Summary
Key Ideas
1 Earth is made up of three layers, namely, the crust, the mantle, and the core.
2 The crust is the outermost and the thinnest layer of Earth.
3 The mantle lies between the core and the crust.
4 The core is the deepest and the hottest layer of Earth, and it is found beneath
the mantle.
5 Diastrophism refers to the deformation of Earth's crust.
6 Isostasy refers to the balance of Earth’s crust such that it floats and elevates
on a denser material based on its density and thickness.
7 The contraction theory states that Earth is shrinking through geological time.
The bigger plates are pushed downward, while the smaller plates are pushed
upward.
8 The convection theory states that the convection currents in the mantle push
the plates upward. This movement causes the deformation and folding in the
crusts.
9 The expansion theory states that Earth's size and mass are expanding.
10 Uplift is the movement of Earth in which the crust is rising.
11 Subsidence is the movement of Earth in which the crust is sinking.
12 Thrust is the movement of Earth in which the crust is moving horizontally.
The Internal Structure of Earth
11
Chap ter Summary
Concept Map
Earth
is composed of
Crust
Mantle
Core
is divided into
Continental
Crust
Oceanic Crust
Upper Mantle
Lithosphere
Asthenosphere
Lower Mantle
12
Earth and Space
is divided into
Outer Core
Inner Core
Chapter Test
I Multiple Choice Questions
Choose the correct answer.
1 Earth's core is mostly made up of
_____.
A aluminum
B magnesium
C iron and nickel
D magnesium and copper
5 The lithosphere and the asthenosphere
are part of the ____.
A atmosphere
B core
C crust
D mantle
2 Which of the following describes
Earth’s asthenosphere?
A A rigid and hard solid rock
B A gas under high pressure
C A liquid at high temperature
D A solid that is able to flow due to
deformation
6 The three main layers of Earth’s interior
are _____.
A the crust, the mantle, and the core
B the crust, the core, and the
lithosphere
C the crust, the mantle, and the
asthenosphere
D the mantle, the inner core, and the
outer core
3 Earth's crust is made mostly of
_____.
A iron and nickel
B iron and silicon
C copper and nickel
D oxygen and silicon
4 The lithosphere consists of ____.
A the asthenosphere only
B the crust and the entire mantle
C the crust and the uppermost
mantle
D the oceanic and continental
crusts only
7 Which of the following statements is
NOT true about the continental crust?
A It forms the continents.
B It is up to 100 miles thick.
C It can be found beneath the ocean.
D It is thicker and less dense than the
oceanic crust.
8 Which of the following statements is
true about the continental crust?
A It forms the continents.
B It covers 90 percent of Earth’s
surface.
C It can be found beneath the ocean.
D It is thinner and less dense than the
oceanic crust.
The Internal Structure of Earth
13
Chapter Test
9 The crust and the uppermost part of
the mantle make up Earth’s _____.
A asthenosphere
B lithosphere
C lower mantle
D core
10 Which of the following statements
correctly describes the core?
A It permits plate motion.
B It is the source of Earth’s heat.
C It is a thin, cold, and rigid layer.
D It helps in maintaining the
magnetic field.
II Structured Questions
True or False. Study each given statement carefully and determine whether it is
correct or not. Explain your answer briefly.
_____ 1 The mantle is the thickest layer of Earth.
_____ 2 The Earth's interior consists of the crust, the mantle, and the core.
_____ 3 The theory of expansion shows gradual changes in the position of the
continents.
_____ 4 As you get closer to Earth’s inner core, heat and pressure increase.
_____ 5 The theory of isostasy states that the rocks form a higher region and slowly
rise while the lower region becomes heavier and slowly sinks.
_____ 6 The inner core creates Earth’s magnetic field.
_____ 7 The asthenosphere plays an important role in the movement of the
lithospheric plates.
_____ 8 Only the oceanic crust floats on the magma.
_____ 9 The mantle is primarily solid, yet it flows under certain pressure.
_____ 10 Earth’s lithosphere consists of the crust and the uppermost part of the
mantle.
14
Earth and Space
Enrichment
Solve the problem.
What’s in the Box?
Liza returned home from school to find a box sitting on the kitchen table. Her
best friend had come to visit her and brought her a present. In order for Liza
to open the present, she had to tell her best friend at least three facts about it.
She could do anything she needed to do to the box except open it to look at the
gift directly. However, she should be careful not to damage the gift. How many
facts do you think Liza can learn about the gift? How is Liza’s challenge related
to earthquakes and to Earth’s interior?
The Internal Structure of Earth
15
Making Connections
Technology
To study how a material behaves under varying pressure, geophysicists use Diamond Anvil Cell (or DAC). This is a small chamber that
has two polished diamonds. A sample of the
material is placed between the two diamonds
where it will be compressed. The pressure
applied to the material can reach up to 6000
gigapascals. Since diamonds are also known
to be transparent to some electromagnetic
waves, spectroscopy and other diffraction techniques can be performed while
the material is being compressed. However, due to small size of the stage, the
size of the material to be analyzed is limited.
Environment
Basalt rocks are igneous, which means that they
came from the lava that cooled down. However,
they are not only known as the main component
of the oceanic crust, but they are also used in
many industries. Unknown to some, basalt rocks
are used for construction and building of roads.
They are also used as grinding stones for grains.
16
Earth and Space
Chapter 2
Plate Tectonics
E
arth’s crust is the substrate of human life. Humans
depend on the resources that are found on it. The
condition of the crust is greatly affected by the
behavior of the plates on it.
In this chapter, the movements in Earth's crust are
explained through the theory of plate tectonics and the
continental drift theory. The effects of such movements
are discussed as well.
LEARNING GOALS
• Explain the different phenomena that occur along plate boundaries.
• Describe the possible causes of plate movement.
• Enumerate the lines of evidence that support plate movement.
2.1 Continental Drift Theory
The continental drift theory was proposed by Alfred
Wegener in the early 20th century. According to the theory,
continents were a single landmass called “Pangaea” that
broke and drifted to their current locations. The fossils
that were found along the coastlines of South America and
Africa were one of Wegener's proofs. Wegener thought
that these animals and organisms could not have swum
over the ocean and that they could have travelled through
land.
Figure 2.1 The coastlines of some of the continents are interlocking.
!
Know More
Alfred Wegener (1880–
1930) started to get
curious to the plate
movements when he
noticed that the coastlines
of some continents fit
with one another.
18
Earth and Space
Polar Wandering
After Wegener’s death, scientists discovered evidence in
support of the continental drift theory through the study
of ancient magnetism called paleomagnetism. Scientists
observed that the basalt rocks on the ocean floor, being
magnetized, tend to line up to Earth’s magnetic field.
Paleomagnetism is the study of ancient magnetism.
magnetic
North
geographic
Pole
North Pole
geographic magnetic
South Pole South Pole
Figure 2.2 Earth's magnetic field direction and
orientation
Geologists observed the rocks that were of the same age,
and came from different continents. They found out that
the rocks were pointing to the same pole. Also, the paths
of the rocks were interlocking as if they were pieces of a
jigsaw puzzle. Then geologists studied more rocks from
a different generation. The paths of those rocks were the
same as the paths of the rocks of the other generation.
However, all paths were separated as if the Earth's
continents tilted, and the poles changed position.
Geologists then conducted another experiment. They
observed that the rocks in North America and Europe.
They noticed that the paths of the rocks with different
ages at those places were interlocking. However, the paths
were separated by a longitude of 30° . This would show
that the pole changed its location, supporting Wegener's
theory. They called this phenomenon polar wandering.
Figure 2.3 The polar wandering curve shows the similarities of Europe
and North America.
Plate Tectonics
19
Let’s Review
1 What is the main idea of the continental drift
theory?
2 Does the magnetism on Earth affect the movements of the plates?
Let’s Do This!
Purpose
Demonstrate how lava from a mid-ridge ocean piles on the ocean floor
What You Need
2 pieces of Styrofoam
poster paint (brown, orange,
red, and green)
water
rice flour
3 trays
What You Need to Do
1 Paint the pieces of Styrofoam brown and let them dry.
2 Fill the trays with water and add 4 spoonfuls of rice flour to each tray.
Make sure that the mixture will not be too viscous. Then add a small
drop of red poster paint to the first tray, orange to the second, and
then green to the third.
3 Place the pieces on top of the rice flour and water mixture carefully.
The pieces should be approximately 1 inch away from each other.
4 Press the pieces of styrofoam downwards slowly until the rice flour
and water mixture flows on top of them. Let the mixture dry on the
pieces.
5 Perform two more trials using the same pieces of Styrofoam by
repeating steps 2 to 4. Use the orange mixture for the second trial and
the green mixture on the third trial.
Guide Questions
1 What happened to the mixture on the Styrofoam after performing the
third trial?
2 How did the second and the third sets of mixture affect the first
mixture on the Styrofoam?
20
Earth and Space
2.2 The Theory of Plate Tectonics
Figure 2.4 Earth's crust consists of major and minor plates.
The theory of plate tectonics was formulated in the
1960s and 1970s as new information was obtained about
the nature of the ocean floor. The theory states that the
lithosphere is broken into large, rigid pieces called plates.
These plates are all moving in different directions and at
different speeds (from 2 cm to 10 cm per year—about the
speed at which your fingernails grow) in relation to one
another. The movements are caused by three different
driving forces.
The theory of plate tectonics states that Earth's
lithosphere is broken into plates that are moving in
different directions.
The slab pull is the driving force caused by the sinking
of the denser oceanic crust. The sinking then pull the
other plates down to the mantle. The ridge push is the
driving force caused by the magma that seeped out
from a divergent boundary. The hot lava pushes the old
plates away. A convection current in the mantle is also
considered as a driving force. When convection occurs in
the mantle, the crusts above are pushed causing them to
move relative to one another.
Plate Tectonics
21
Evidence for Plate Tectonics
Scientists gave a diverse body of evidence that supports
the theory of plate tectonics. Here are some bits of the
evidence:
!
Know More
A phenomenon called
seafloor spreading
occurs at the divergent
boundary. As the seafloor
is pulled apart, the magma
rises from the mantle. This
lava is cooled by the sea
water , thus, creating a
new layer of ocean floor.
1 Positioning technologies like the global positioning
system (GPS) satellite laser ranging and very long
baseline interferometry show direct measurement as
the crust moves in well-defined patterns.
2 Continental margins have a close fit like South America
and Africa.
3 As the age of seafloor basalts decreases, their distance
from ocean ridges decreases as well.
4 As continental margins are reconstructed, there is
evidence of geological continuity as shown by the
identical fossils found in different continents.
5 There is continuation of geologic structures from one
continent to another, which are now separated by
oceans (for example, the Appalachian-Caledonian
mountain chain).
Plate Boundaries
Plates that make up Earth’s crust meet at plate boundaries.
When plates move, stress builds up at those boundaries.
Stress, when released, causes movements in the crust. It
is the reason why volcanoes and mountains are usually
formed and earthquakes occur near plate boundaries.
Figure 2.5 Active volcanoes, plate tectonics, and the "Ring of Fire"
22
Earth and Space
Depending on how two plates are moving in relation to
one another, there are three types of plate boundaries,
namely, convergent, divergent, and transform boundaries.
These types and their descriptions are listed on a table
below.
Type of
Boundary
Convergent
boundary
Divergent
boundary
Transform
boundary
Description
This is a boundary between
colliding plates. Plates only
move a few centimeters
each year, so collisions are
very slow; and they last for
millions of years. Volcanic
activities can occur at this
type of boundary.
This is a boundary between
plates that separate from
one another. As the plates
separate along the boundary,
the block between the faults
cracks and drops down into
the asthenosphere. Volcanic
activities can also occur at
this type of boundary.
This is a boundary where
plates slide past one
another. It is marked in
some places by linear
valleys along the boundary
where rock has been ground
up by the sliding. Volcanic
activities do not occur at
this boundary.
volcanoes (volcanic arc)
trench
earthquakes
ridge
lithosphere
asthenosphere
earthquakes
within crust
Let’s Review
1 Differentiate between the three types of
boundaries.
2 Give three pieces of evidence for plate tectonics
theory.
Plate Tectonics
23
Let’s Do This!
Purpose
Demonstrate how to form the world map using the principle of jigsaw
puzzle
What You Need
picture of the world map printed on an 8.5” x 11” paper
paste or glue
scissors
cardboard
What You Need to Do
1 Paste the picture of the world map on the cardboard and let it dry.
2 Draw lines on the map. The lines should be far from one another,
enough to make a jigsaw puzzle.
3 Cut along the lines that you have drawn.
4 Exchange jigsaw puzzles with your classmate.
Guide Question
What are the clues that you used for putting the pieces of the puzzle
together? Can those clues support the continental drift theory?
24
Earth and Space
Chap ter Summary
Key Ideas
1 The continental drift theory states that the continents of the world were once
a single landmass that broke, and that they drifted to their current locations
through geological time.
2 Paleomagnetism is the study of ancient magnetism.
3 Polar wandering is a phenomenon wherein Earth's magnetic pole changed
its location through geological time.
4 The theory of plate tectonics states that lithosphere is broken into plates that
are moving in different directions.
5 The ridge push is the driving force caused by the magma that seeped out
from a divergent boundary that pushes the old boundaries away.
6 The slab pull is the driving force caused by the sinking of the denser oceanic
crust. The sinking then pulls the other plates down to the mantle.
7 A convection current causes plate movements by pushing the plates upwards
when heat is transferred in the mantle.
8 A plate boundary is where two plates meet.
9 A divergent boundary is the boundary between plates that are separating
from each other.
10 A convergent boundary is the boundary between colliding plates.
11 A transform boundary is the boundary between sliding plates.
Plate Tectonics
25
Chap ter Summary
Concept Map
Plate Tectonics
involve
Plate
Movements
driving forces
Slab Pull
are explained by
Continental
Drift Theory
occur along
Plate
Boundaries
include
Ridge Push
Convergent
Boundaries
Convection
Currents
Divergent
Boundaries
Transform
Boundaries
26
Earth and Space
Chapter Test
I Multiple Choice Questions
Choose the correct answer.
1 According to the theory of plate
tectonics, __________.
A the asthenosphere is strong and
rigid
B the lithosphere is divided into
plates
C the asthenosphere is divided
into plates
D the asthenosphere moves over
the lithosphere
2 According to the plate tectonics
theory, a plate can be made up of
__________.
A mantle
B oceanic lithosphere only
C continental lithosphere only
D both continental and oceanic
lithosphere
3 How are plates moved?
A By compressional forces
B By contraction of the crust
C By convection currents in the
mantle
D By the eruptions of lava from
volcanoes
4 The theory of plate tectonics helps
scientists explain __________.
A convection current
B slab pull
C how earthquakes and volcanic
eruptions occur
D why Earth’s core is less dense
than the mantle
5 Active volcanoes do not form at
__________.
A transform boundaries
B divergent boundaries
C the center of continents
D convergent boundaries
6 A convection current, a ridge push,
and a slab pull work together to
produce __________.
A earthquakes
B boundary
C continental lithosphere
D constant plate motion
7 What do scientists use the global
positioning system?
A To measure Earth’s thickness
B To measure plate motion
C To make images of tectonic
plates
D To measure the distances of
boundaries
8 Which of these does not provide
evidence for the continental drift
theory?
A Fossil records
B Paleomagnetism
C Seafloor spreading
D Ridge push
Plate Tectonics
27
Chapter Test
9 The study of paleomagnetism
revealed that __________.
A Earth’s crust has basalt rocks
B Earth’s magnetic field poles have
tilted
C the rocks of the seafloor are less
than 200 million years old
D drifting continents follow Earth’s
magnetic lines of force
10 Colliding plates meet at a _________.
A Convection current
B Divergent boundary
C Transform boundary
D Convergent boundary
II Structured Questions
True or False. Study the statements carefully and determine whether it is correct or
not. Explain your answer briefly.
_____ 1 T
he theory of plate tectonics is an accurate description of why Earth's surface
has changed over time.
_____ 2 Slab pull boundary is a boundary where melting plates meet.
_____ 3 Paleomagnetism is the study of modern magnetism.
_____ 4 Alfred Wegener proposed the continental drift theory.
_____ 5 Polar wandering is a phenomenon that shows Earth’s magnetic pole is
changing its location through geological time.
Enrichment
Construct a three-dimensional model of each type of plate boundary showing
typical earthquake foci depths and the structures that tend to result at each
type of boundary.
28
Earth and Space
Making Connections
Technology
Physicians are not the only ones that use tomography scans to get images of
internal parts. Geologists have their version of CT scan but instead of using
X-rays, they use seismic waves. This technique is called seismic tomography.
This is used to generate computed and 3-D images of the plates. It is also
used to determine the thickness of the plate and to observe its formation and
evolution.
To generate images, through seismic tomography, geologists use seismic
waves from earthquakes. The time for seismic waves to reach the receiver is
used to calculate the speed of the waves. If it takes longer for the waves to
reach the station, then there is a material that is blocking the wave.
Plate Tectonics
29
Making Connections
Environment
Unknown to some, plate
movements have a great
effect on climate change. One
effect is the volcanic eruption
that causes the emission of
CO2. Volcanoes are usually
formed at convergent and
divergent boundaries. As the
plates move, stress builds up
at the boundaries. This stress
then triggers the eruption.
Too much of the gas in the
environment can increase the
green house effect.
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Earth and Space