Unit 3 – Inside the Earth

Unit Essential Question (EQ) : How do events that take place inside the Earth cause changes on its surface?

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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?

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Concept#1 – Earth’s Layers Vocabulary Words for this lesson:

– Crust– Mantle– Core– Density– Composition

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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?

Concept #2: Plate Tectonics

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Vocabulary for this lesson

Lithospheric plates Convection currents Plate tectonics Faults Plate boundaries (convergent,

divergent, transformed)

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Vocabulary (continued) Continental drift Subduction Sea floor spreading Pangaea Mid-ocean ridge

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Concept #3 Subsurface TopographyLesson Essential Question:

•How are the geological features (landforms) that exist on land similar to the geological features on the ocean floor?

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Concept #3 Vocabulary

Subsurface topographyContinental shelfContinental slopeTrenchAbyssal plainSonarSeamount

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Lesson Essential Questions:•How do earthquakes affect Earth’s surface?

•How do volcanoes affect Earth’s surface?

Concept #4 Earthquakes and Volcanoes

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Concept #3: Earthquakes and Volcanoes Vocabulary List

Epicenter TsunamiFaults Hot spotseismic waves Ring of FireFocus Richter ScaleMagnitude Stress

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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 LayersCrust layer

Crust layer

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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.

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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

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Characteristics of crust layerThe 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

Lower mantle layer

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Upper mantle layer

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 OxygenMagnesium Iron

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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

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Upper Mantle Layer

The upper mantle is made up solid rock

Temperature is 1,600° F (870° C)

Lower Mantle Layer

The lower mantle is made up of melted rock and flows very slowly like a thick liquid

Temperature is 4,000-6,700° 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

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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 TectonicsLesson 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?

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Theory of Plate Tectonics

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Continental Drift Theory

Theory (idea) developed by a German scientist, Alfred Wegener, in the early 1900s

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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

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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

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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

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Seafloor spreading

Theory of Plate Tectonics

What is it?–This theory was developed in the 1960s.

–Combined the ideas of continental drift and seafloor spreading.

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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

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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

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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 earthquakes)

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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

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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

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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

                                           

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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 TopographyLesson Essential Question:

•How are the geological features (landforms) that exist on land similar to the geological features on the ocean floor?

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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?

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Epicenter Richter ScaleSeismic Waves TsunamiFocus FaultsRing of Fire VolcanoesStress EarthquakesMagnitude

As we study each word, you will check them off on your student concept map.

Vocabulary for this lesson

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Lesson # 3

In this lesson we will explore

–The effects earthquakes have on Earth’s surface

–The effects volcanoes have on Earth’s surface

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At the end of this lesson you will be able to–

Lesson # 3: