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Unit 3 – Inside
the Earth
Unit Essential Question (EQ) :
How do events that take place
inside the Earth cause changes
on its surface?
1
Concept #1: Earth’s Layers
 Lesson
#1 EQ: How can you
compare and contrast the
Earth’s layers in relation to
temperature, density, and
composition?
2
Concept#1 – Earth’s Layers

Vocabulary Words for this lesson:
– Crust
– Mantle
– Core
– Density
– Composition
3
Concept #2: Plate
Tectonics
 Lesson
#2 EQ:
• How does the theory of plat
tectonics explain the changes
that occur on Earth?
• What evidence do scientists
have that the continents were
once joined together?
4
Vocabulary for this lesson
Lithospheric plates
 Convection currents
 Plate tectonics
 Faults
 Plate boundaries (convergent,
divergent, transformed)

5
Vocabulary (continued)
Continental drift
 Subduction
 Sea floor spreading
 Pangaea
 Mid-ocean ridge

6
Concept #3 Subsurface
Topography
 Lesson
Essential Question:
• How are the geological
features (landforms) that
exist on land similar to the
geological features on the
ocean floor?
7
Concept #3 Vocabulary
Subsurface topography
Continental shelf
Continental slope
Trench
Abyssal plain
Sonar
Seamount
8
Concept #4 Earthquakes
and Volcanoes
 Lesson
Essential Questions:
•How do earthquakes affect
Earth’s surface?
•How do volcanoes affect
Earth’s surface?
9
Concept #3: Earthquakes
and Volcanoes

Vocabulary List
Epicenter
Faults
seismic waves
Focus
Magnitude
Tsunami
Hot spot
Ring of Fire
Richter Scale
Stress
10
Lesson #1: How can you compare and
contrast the Earth’s layers in relation to
temperature, density, and composition?

The Earth has three
different layers:
– Crust
– Mantle
– Core

Temperature and
pressure increases
as you go deeper
into the Earth
through each layer
Crust
Mantle
Core
11
Earth’s Layers
Crust layer
Crust
layer
12
Earth’s Layer: Crust layer
The
top layer of the
Earth is called the crust.
This
is the layer that we
live on, and it also the
thinnest layer.
13
Earth’s Layers - Crust layer
It
is thick in some places
and thin in others.
The
crust is divided into
large sections called
continental plates.
Characteristics of crust
layer
 Composition:
•Made up of loose igneous,
sedimentary, and
metamorphic rocks and soil
•Elements found in the crust
include silicon, aluminum,
calcium, sodium and potassium
15
Characteristics of crust
layer
 The
Crust layer is made up of
two layers
•Density:
–continental crust (below
the continents) – 32 to 70
km thick
–oceanic crust (below the
oceans) – 5 to 10 km thick
Earth’s Layers – Mantle layer
Upper
mantle
layer
Lower
mantle
layer
17
Earth’s Layers - Mantle layer
 The
next layer below the crust
is the mantle layer and is the
largest layer.
 Composition:
There are several
elements in this layer:
Silicone
Oxygen
Magnesium
Iron
18
Earth’s Layers - Mantle layer
 Density:
The mantle layer is
about 2900 km thick and is
divided into two parts which
are the upper mantle and
lower mantle
19
Upper Mantle Layer
 The
upper mantle is made up
solid rock
 Temperature
(870° C)
is 1,600° F
Lower Mantle Layer
 The
lower mantle is made up of
melted rock and flows very
slowly like a thick liquid
 Temperature
is 4,0006,700° F (2,200-3,700° C)
Earth’s Layers - Core layer
Outer core
Inner
core
22
Earth’s Layers - Core layer
 This
is the layer below the
mantle and is the center layer
of the Earth
 Density:
It is about 3500 km
thick and 3900 km below the
Earth’s surface
23
Earth’s Layers - Core layer
 This
layer is very dense and
under great amounts of
pressure
 Temperatures
in this layer
are extremely high (hotter
than the SUN!)
Earth’s Layers Parts of the Core layer
 The
core is divided into two
layers
– Outer core
• Composition: Liquid layer
made up of melted iron and
nickel
• Density: About 2200 km
thick
25
Earth’s Layers Parts of the Core layer
 Inner
core
• Composition: Solid layer made
up of iron and nickel
• Density: About 1300 km
thick
• Temperature: Can get up to
about 13,000°F (7,200°C =
7,500 K)
Concept #2: Plate Tectonics
 Lesson
Essential Questions:
– How does the theory of plate
tectonics explain the changes
that occur on Earth?
– What evidence do scientists
have that the continents were
once joined together?
27
Theory of Plate Tectonics
28
Continental Drift Theory

Theory (idea)
developed by a
German scientist,
Alfred Wegener, in
the early 1900s
29
Continental Drift Theory

What is it?
– Theory that continents were once
connected like a jigsaw puzzle (about
200 million years ago) which he called
Pangaea (which means “all land”)
– Somehow the continents drifted apart
but he didn’t know why
30
Proving the Continental Drift
Theory
 What
evidence (proof) did he have
to support his idea (theory)?
– Similar animal fossils of found on
different continents help support
this theory
– Plants that once grew on
continents with warmer climates
were found as fossils on
continents with colder continent
31
Proving the Continental Drift
Theory

Rocks also gave clues that supported
the idea that continents were once
connected
• The same rocks could be found
around the land area where the
continents were once connected but
are now separated.

The idea of seafloor spreading helped
provide more information to support the
continental drift theory.
32
Seafloor Spreading
 What
is seafloor spreading?
– As the plates move farther apart,
magma from the Earth’s interior
moves up to fill the gap,
sometimes leading to the eruption
of undersea volcanoes. This
process, called seafloor
spreading.
– This is how new seafloor is
formed.
33
Seafloor spreading
34
Theory of Plate Tectonics
 What
is it?
– This theory was developed in
the 1960s.
– Combined the ideas of
continental drift and seafloor
spreading.
35
Theory of Plate Tectonics
 The
theory states that the
Earth’s surface is divided into
large sections called plates that
the continents and oceans rest on.
 These
plates moves around on top
of a plastic-like layer of the upper
mantle called the Asthenosphere
Cross Section of the Lithosphere
and the Asthenosphere
37
Theory of Plate Tectonics
 These
plates move in different
directions and at different
speeds.
 Rate
of movement is very slow
(about .5 to 6 inches in a year)
over time.
Theory of Plate tectonics
 The
are seven major plates in the
Lithosphere:
– the African, North American,
South American, Eurasian,
Australian, Antarctic, and Pacific
plates.
 There
are also several minor plates
that also exist, including the
Arabian, Nazca, and Philippines
plates.
39
Continental Plates
40
Theory of Plate Tectonics

The plates in the Lithosphere are
moving around like cars in a
demolition derby, which means they
sometimes crash together, pull apart,
or sideswipe each other.

The place where the two plates meet
is called a plate boundary.
Theory of plate tectonics –
plate boundaries

Boundaries have different names
depending on how the two plates are
moving in relationship to each other
– crashing: Convergent Boundaries
(forms earthquakes, mountains, and
volcanoes)
– pulling apart: Divergent Boundaries
– or sideswiping: Transform
Boundaries (forms faults that cause
42
earthquakes)
The first type of plate
boundary (place where plates
meet) we will talk about is
called a convergent
boundary.
Plate Boundaries –
Convergent Plate Boundaries

This is the place where two plates
converge, or come together

One plate will sink and disappear
under the other plate. This process
is called subduction.

The area where subduction takes
place is the subduction zone.
Convergent boundaries
 What
happens in the subduction
zone?
– The area where subduction
takes place is the subduction
zone.
– The plate that subducts, or
sinks under the other plate,
melts and becomes magma.
What happens in the
subduction zone?
 The
newly formed magma is
forced upward along the plate
boundary.
 Just
above the area where the
magma shots upwards,
volcanoes form.
What is formed from
convergent boundaries?

When a oceanic plates sinks under a
continental plate volcanoes form

When a oceanic plate sinks under
another oceanic plate volcanoes form
that will become islands.

When two continental plates collide, one
does not sink under the other and
subduction does not occur. This type of
collision forms mountains.
Convergent plate boundary
48
The second type of plate
boundary (place where plates
meet) we will talk about is
called a divergent boundary.
Plate tectonics –
Divergent Plate Boundaries
 When
two plates move apart, the
area formed between those two
plates is called the divergent
boundary
 As
plates pull apart, magma pushes
up and becomes new seafloor.
 In
some areas where plates pull
apart, rift valleys form.
Divergent plate boundary
51
The third type of plate
boundary (place where plates
meet) we will talk about is
called a transform
boundary.
Plate tectonics –
Transform Plate Boundary

This type of plates boundary happens when
two plates slide past each other

Plates can slide past each other in two
directions
– Going the same direction
– Going the opposite direction but at different
rates

Plates sliding past each other cause
earthquakes (example San Andreas Fault)
Plate tectonics – Transform
boundary
54
What causes Plate tectonics?
 Scientist
are not sure why but they
believe you can compare how it
takes place to how you heat up a
can of soup…by convection
currents.
 What
are convection currents?
What are convection currents?
 Scientist
believe that as the plates
heat up the denser plates get
hotter and rises above the less
dense cooler plates. This change is
temperature and density is thought
to cause plate movement.
(Continued on the next slide)
What are convection currents?

As the hotter plates rise to the top,
it starts to cool and sinks back down.

This pushes the cooler plates that
had sunk down to the bottom towards
the top.

This continuous cycle of heating,
rising, cooling, and sinking is called a
convection current.
Features caused by Plate
Tectonics

Mountains (by a process called
subduction)

Earthquakes

Volcanoes

Islands
58
Concept #3 Subsurface
Topography
 Lesson
Essential Question:
• How are the geological
features (landforms) that
exist on land similar to the
geological features on the
ocean floor?
59
Concept #3 Subsurface
Topography
– Draw what you think the ocean floor
looks like.
– View Brain Pop Video “Ocean Floor”
– View Power Point Presentation and
Discuss Ocean Topography
– Complete Workbook pages
– Label Parts of the Ocean Floor
– Compare/contrast your drawing of the
ocean floor with the actual ocean floor
diagram.
– Review Brain Pop and take Quiz
Concept #3 Subsurface Topography

Vocabulary for this
lesson:
– Subsurface
topography
– Continental shelf
– Continental slope
– Abyssal plain
– Guyot
– Seamount
– Deep-ocean trench
What is subsurface
topography?

Subsurface topography simply
describes the physical features of the
ocean floor.

Subsurface means below the surface or
ground level.

Topography means knowing, locating, and
labeling these physical features.
How have scientist mapped the
ocean floor?



Because it is impossible to actually see
the ocean floor, scientist that map the
ocean floor, called oceanographers, use a
method called echo sounding.
Echo sounding measures the time it
takes a pulse of sound (sound wave) to go
from the ship to the ocean floor and
then back to the ship.
Using this technique, scientist have been
able to map features or parts of the
ocean floor.
Parts of the Ocean’s Subsurface
Topography (Ocean Floor)
Abyssal Plain
Define the parts of the Ocean
Floor
Continental Shelf
 Continental Slope
 Abyssal Plain
 Seamount
 Guyot
 Deep Sea Trench

Define Parts of the Ocean
Floor

Continental Shelf – Marks the beginning of
the ocean shoreline. This is the end part
of the continent that gradually extends
into the ocean.

Continental Slope – a steep drop from the
continental shelf down to the ocean floor.

Abyssal Plain – is the flattest part of the
deep ocean floor formed by sediment
from the land that has settled over time.
Define Parts of the Ocean Floor

Seamount – inactive volcano peaks

Guyot – A flat-topped seamount flattened
by the action of waves (force of erosion).

Trench – a long, narrow, steep-sided
depression where one plate sinks
underneath another (volcanoes and
earthquakes can take place here).

Sonar – stands for sound navigation and
ranging. It is a system that uses sound
waves to calculate distance to an object.
Compare geological features found on
land to the ones found in the ocean

Trenches in the ocean are similar to valleys
found on land. The ocean trenches are
usually longer and deeper than any valley
found on land.

The Abyssal Plain found in the ocean is
similar to plains or flat areas of land found
on surface.

Volcanic cones that form underwater, called
seamounts, rise to form volcanic islands
above water (this is how Hawaii was formed).
Concept #3 Subsurface
Topography

Label the ocean features in the diagram
on your handout.

Lab activity “Model of the Ocean Floor”

Compare/contrast your drawing of the
ocean floor to the diagram you labeled
during the lesson.

Watch Brain pop clip “Ocean Floor” and
take quiz.
• Concept #4 Lesson Essential
Questions:
How do earthquakes affect
Earth’s surface?
How do volcanoes affect Earth’s
surface?
70
Vocabulary for this lesson
Epicenter
Seismic Waves
Focus
Ring of Fire
Stress
Magnitude
Richter Scale
Tsunami
Faults
Volcanoes
Earthquakes
As we study each word, you will check
them off on your student concept map.
71
Lesson # 3
 In
this lesson we will explore
– The effects earthquakes
have on Earth’s surface
– The effects volcanoes have
on Earth’s surface
72
Lesson # 3:
 At
the end of this lesson you will
be able to
–