Structure of the Earth

Chapter 3

Section 1 Layers of the Earth

Objectives:Describe and compare the crust, mantle, and coreDescribe the structure of the lithosphereExplain why matter within the asthenosphere movesMake a model of the earth and its layers

Skills Warm-up

Layer by LayerList different objects that are made up of layers.Classify them based on number, type, and thickness of layers.Do most of the objects contain soft or hard centers?

Earth’s InteriorEarth’s surface is made up of ______, ______, and _______

At one time, people thought earth might be ___________

In 1864, Jules Verne wrote “Journey to the Center of the Earth”

What do you think is between earth’s surface and its center?

Earth’s Interior

What would you find if you could bore a hole deep into the earth until you reached its center?

1. The _________ __________of the materials changes as you go __________

2. Materials increase in ________ as you go __________

3. __________ and _________ increase with depth, but at different rates

The way that these factors ________ in the earth’s interior produces ________ with different ________ __________ and different ________ __________

Layers of the Earth

3 Main Layers based on ___________ properties:

________ – outermost layer of the earth

________ – middle layer of the earth

________ – innermost layer of the earth

Activity

Watch parts of Journey to the Center of the Earth

Chemical Makeup of Layers

From _________ to _________:Crust – contains rocky ________ (silicon/oxygen compounds) rich in _________ (Al), _______ (Fe), and ___________ (Mg)

Thickness varies from _______to _______

Mantle – dense, mostly _____ and ____ _________Makes up ________ of Earth’s volume

Makes up ________ of Earth’s mass

Core – very dense, mostly two metals: ___ and ___

Makes up ________ of Earth’s mass

Makes up ________ of Earth’s volume

Physical Makeup of Layers

3 Main Layers based on ___________ ___________:• The _____________

includes the crust and outer mantle – it is strong, cold and rigid

• The _____________ is just below in the mantle - it is hot, semi-liquid, and easily deformed (plasticity)

• The ______________ (mantle) below the asthenosphere – very strong and rigid because temperature isn’t high enough

Physical Makeup of Layers

______ ______– liquidTemperature overcomes pressureCirculation of molten Fe is source of magnetic field?

______ ______– solidVery high pressure overcomes high temperature

Physical Properties of Layers

____________________ deep inside the earth are ______ __________to melt the silicates and other substances that make it up

But, most of the earth’s interior is not ___________

Why????

Physical Properties of Layers

_________ inside the earth offset the high temperatures_______ pressures will not allow the earth’s matter to _______

Physical Properties

• _________ between __________ and ________ varies with depth of each of earth’s layers

• Depending on this balance, matter can be ________, ________, or ___ _________

• ___________ – condition where the right balance of pressure and temperature makes _______ material _______ and ___________, but not completely liquid

Questions So FarAnswer the following 10 questions on a sheet of paper and hand them in at the

end of class (use your guided notes)

1. How thick is the crust and what does it contain?

2. What materials does the mantle contain?

3. How much of the earth’s volume does the mantle make up? How much of the earth’s mass?

4. Which layer is more dense, the mantle or the core? (Remember D = M/V)

5. What materials account for the density of the earth’s core?

Questions So Far6. Based on their characteristic physical properties, what are the 5 zones of the earth?

7. What does the lithosphere include?

8. What is the hot, soft, and flowing condition of the asthenosphere called?

9. What is the physical condition of the outer core? Why?

10. What is the physical condition of the inner core? Why?

Skills Warm-up

Crust:What objects besides the earth have crusts?How are their crusts similar to and different from the earth’s crust?

Structure of the ____________

Two distinct parts:

___________ _______Less dense because of higher percentage of silicon and oxygen, has more aluminumContains rocks called rhyolite and granite

___________ _______More dense and darker in colorContains rocks called basalt and gabbro

Which varies in thickness more?

Movement in the ______________Material is ________ and ________ – like hot tar

Intense heat from Earth’s core causes this material to _____________

Matter ______ as it heats, then cools and slowly _______

The result – ___________, a circular flow of matter that is very slow, but has important effects!

Living on Oceanic Crust

Most oceanic crust is covered with _________

But many islands and the surface of some continents are made of oceanic crust

_________ __________

___________

___________ __________ (Idaho, Washington, Oregon)

Oceanic crust soil is not as ________ because of large amounts of _______ and ____________

Can be used to grow _________, _________, and ____________ or to graze ____________

. Hawaii

Iceland

Graphing Activity Temperature Changes in then

EarthEach student should complete the graphing activity using the data and the graph paper that I give out.

If it is not completed in class, it must be done for homework.

Plasticity Activity

Section 2 Studying the Earth’s Interior

Objectives:Identify two types of seismic wavesDescribe the movement of seismic wavesExplain how earth scientists make inferences about the earth’s coreInfer the characteristics of an object through indirect observation

Skills Warm-up

Boiling Over:Without removing the cover from a pot cooking on the stove, how could you determine what was cooking inside?How might your method of determining the pot’s contents be similar to the way scientists determine what is inside of the earth?

How do we know it’s hot in there?

How do we know what the chemical makeup is?

How do we know that some parts are liquid and some are solid?

Studying the Earth

Studying the EarthThe interior of the earth _______ be observed _________

Deepest mine is ___ ____ _______

Deepest hole ever bored into the crust went down only ________ – still far from the mantle

Earth’s _________ does provide some clues

________ _______(magma) from volcanoes is evidence for high temperatures inside the earth

But most knowledge has come from ________ ___________ of how _______ _________from earthquakes travel

Shock Waves• You have all

probably experienced shock waves

• Have ever hit a baseball or softball with a bat?

• The vibrations or shock waves travel through the bat to your hands

• Shock waves can also travel through the _______

Seismic Waves____________ – sudden movements in the crust that can cause shockwaves

________ _____– shock waves from an earthquake

can pass from one side of the Earth to the other

__________ – instrument that detects seismic waves.

Located all over Earth’s surfaceScientists gain valuable information about the interior of earth by comparing the ________ and ________ _______of waves

Types of Seismic WavesThe two types most useful for studying the Earth’s interior are:

____ _______ travel in a _______________ movement of rock particles. Particles are squeezed together, then pulled apart.

____ _______ travel in an ______________ movement of rock particles.

S waves cannot travel through __________

Speed and Bending of Waves

_______ at which waves travel depends partly on the ________ of the rock it travels through

The higher the density, the ________ the speedAs a wave passes through the Earth and encounters rock types with different densities, its speed __________

If a wave passes through rock layers at a slight _______, a change in speed can cause it to change _____________

Speed and Bending of Waves

Most seismic waves travel in a ________ path through the Earth. This curving is called _________

When a wave passes into a rock of a different ________, its path may ______ sharply

Inferring from Seismic Waves

With knowledge of how seismic waves travel, scientists have:

Located the _________ between earth’s ________Inferred the ________/_________ __________ of layers

Andrija MohorovicicCroatian scientist

In 1909 he discovered the boundary between the earth’s ______ and _________

The Moho_________ ___________– “Moho”, the boundary between the crust and the mantle.

At a depth of between ____and ____km below the surface, seismic waves suddenly ______ _____

At this depth, rocks became much more ______, and probably of a different ________ ________

The CoreWhen an earthquake occurs, it sends seismic waves in ____ _______

P and S waves are detected by ______________

At a certain distance away from where the earthquake occurs starts a zone in which ____ _________can be detected

Called the _________ _______ – caused by the Earth’s ________

The CoreNote that __________ __________ from the earthquake, only ____ ________ are detected. What does this tell you about the core?

It suggests that at least part of the core is _______ since no ____ ________ are detected

The size of the earth’s core can be calculated from the size of the _________ ________

Answer the following questions:

Where do the seismic waves from an earthquake go?

What happens as P waves strike the core? Why?

Which waves cross the core?

Which waves are detected in the shadow zone?

What can be used to calculate the size of the core?

Activity – How Does Matter in the Mantle Move