Journey to the Center of the Earth

Journey to the Center of the Earth

by Judy Hutton

First, lets review density!

Multiple Choice

If an object is less dense it will.....

• sink

• float

Multiple Choice

If an object is more dense it will.....

• sink

• float

Multiple Choice

Based on what we know about density, would we find more dense layers in the center of the Earth or less dense layers in the center of the Earth?

• More dense in the center

• Less dense in the center

Earth's Composition

-The Earth is divided into three layers Based on Composition- the crust, the mantle, and the core.-These layers are made up of different elements and compounds.

-The less dense compounds make up

the crust and the mantle.

-The more dense compounds make up

the core.

​-The Earth is divided into Five layers

Based on How it behaves Mechanically

​The Lithosphere, the Asthenosphere,

The ​Mesosphere, the Outer Core and

the Inner Core

Lets start with the Crust

The Crust

The crust is the outermost layer and the thinnest

 There are two types of crust: continental and oceanic.

Both crusts are made mainly of the elements oxygen, silicon, aluminum. (Rocks and minerals)

The Crust

• Usually between 3-25 miles thick (5-40 km)

• Can be as thick as 80 km under mountains and very thin beneath the ocean

Oceanic Crust

• The part of the crust that lies beneath the ocean is called oceanic crust

• It is made of basalt, which typically forms from cooling lava

Continental Crust

• Continental crust is what forms all of Earths' land masses

• Depending on the location, the composition varies greatly

• Overall, it is mostly types of granite

Multiple Select

What are the two types of crust?

• Oceanic

• Continental

• Thick

• Tectonic Plate

The Mantle

The layer of the Earth between the crust and the core.

The mantle is much thicker than the crust and contains most of the Earth’s mass (84%)

The mantle has more magnesium and less aluminum and silicon than the crust, making it much more dense

The Mantle

The mantle is made of very hot rock, but still solid. It is nearly 3,000 km thick, and we divide it into 3 main layers based on physical characteristics.

Upper Mantle

The Lithosphere: Made up of two parts- the crust and the rigid upper part of the mantle. This is where tectonic plates are found.

​

The Asthenosphere: Plastic / Silly putty like part of the mantle that the lithosphere sits on.

​

Convection currents in the mantle cause movement. Movement of the asthenosphere causes movement of the over-riding tectonic plates.

Lithosphere

• The crust and upper part of the mantle have very similar compositions

• We group them together into a single layer called the lithosphere

• Averages about 100 km thick

• ​Made mostly of Silicates rocks.

• ​Broken into Plates

• ​Thicker, lighter Continental plates

• ​Heavier, thinner Oceanic Plates

Asthenosphere

• A soft layer of upper mantle, just beneath the lithosphere

• Material is hotter and under higher pressure

• This layer can bend and "flow" like a melted plastic, but is still solid

Mesosphere

• This layer is hotter but more stiff than the asthenosphere

• This is due to the increasingly high pressure

• Includes the lowest part of the mantle and part of Earth's core

Multiple Choice

What is denser? The lithosphere or the asthenosphere?

• Lithosphere

• Asthenosphere

Multiple Choice

What is the second (2) layer of the Earth?

• Mantle

• Crust

• Core

Multiple Choice

What is the first (1) layer of the Earth?

• Core

• Mantle

• Crust

Multiple Choice

Which layer of the Earth is shown in YELLOW?

• Crust

• Mantle

• Inner Core

• Outer Core

Multiple Choice

The mantle is the ______ layer of the earth

• thinnest

• thickest

• coldest

• hottest

Multiple Choice

Starting from the crust and traveling to the inner core. It will become

• More dense the deeper you go

• less dense the deeper you go

• colder at every stage

• nothing changes from top to bottom

Multiple Choice

The mantle becomes ______dense the lower you go

• less

• more

The Core

The Outer Core: The liquid layer of the Earth’s core that lies beneath the mantle and surrounds the inner core.

The Inner Core: The solid, dense center of our planet that extends from the bottom of the outer core to the center of the Earth. (3,964 miles beneath the surface)

The Core

• The core is made mostly of the dense metals, iron and nickel.

• Consists of 2 layers: the outer and inner core

• Total radius = 3,480 km

Outer Core

• A layer of molten Iron and nickel metals surrounding the inner core

• The intense heat causes the metals to melt, making this layer a liquid

• 2,258 km thick

• ​Flowing Iron creates the Earths Magnetic Field!!!

The Core and Earth's Magnetic Field

Scientists believe that movements inside the liquid outer core as it flows around the Inner Core are what creates the magnetic field around the Earth.

This Magnetic field is what protect the planet from the Sun's deadly radiation.

​The field lights up when stuck by high energy radiation causing the Aurora's (Northern Lights)

Inner Core

• A dense ball of solid metal

• This section is so dense and under so much pressure, the atoms in the Iron metals can not melt and stay solid

• 1,222 km thick

Solar Wind and Earth’s Magnetic Field

​The Earths magnetic field is called the Magnetosphere, It protects us from solar winds and cosmic radiation.

​

Solar wind is a supersonic plasma

​

Plasma is electrically charged particles or ions that flows outward from Sun at high speeds & bathes planets in a flood of high-energy particles. (Which isn’t very good for us!)

Solar Wind and Earth’s Magnetic Field

The auroras are created when 

high-energy particles in Van Allen belts collide with gases in Earth’s atmosphere & give off light

The Strength of Earth’s Magnetic Field

​Jupiter has a super-strong magnetic field.

Mars lost it's Magnetic Field because it cooled enough for it's core to become solid (it no longer flows). The incoming radiation is what prevents life on the surface of Mars.

Our magnetic field is decreasing by 5% a century.

What would happen if our magnetic field became weaker? 

Multiple Choice

Which layer is at the center of the Earth?

• Inner Core

• Outer Core

• Continental Crust

• Oceanic Crust

Multiple Choice

This layer spins as the planet rotates and creates Earth's magnetic field.

• Inner Core

• Outer Core

• Mantle

• Crust

Multiple Choice

Which is made of Liquid?

• Core

• Outer core

• Inner core

Multiple Choice

What is the Core made of?

• Oxygen and Silicon

• Magnesium and Nickel

• Iron and Nickel

• Oxygen and Iron

Open Ended

Put the layers of the Earth in order from the outermost layer to the innermost (including the upper mantle)

Multiple Choice

True or False. The mantle is hotter than the crust.

• True

• False

Multiple Choice

True or False. The Earth's crust is thicker than the inner layers.

• True

• False

Multiple Choice

What layer of the mantle is flexible like plastic?

• lithosphere

• asthenosphere

• lower mantle

Multiple Choice

What causes the asthenosphere to move?

• Convection currents

• Outer Core

• Inner Core

Multiple Choice

What is denser? The lithosphere or the asthenosphere?

• Lithosphere

• Asthenosphere

Multiple Choice

True or False. The Earth's crust is thicker than the inner layers.

• True

• False

Multiple Choice

What layer of the mantle is flexible like plastic?

• lithosphere
• asthenosphere
• lower mantle

Multiple Choice

True or False. The mantle is hotter than the crust.

• True

• False

Open Ended

Put the layers of the Earth in order from the outermost layer to the innermost

Multiple Choice

What part of the earth generates our magnetic field?

• Atmosphere

• Surface

• Plate tectonics

• Core

Multiple Choice

Why doesn't Mars have a strong magnetic field?

• It doesn't have a metal core

• It doesn't have an atmosphere

• Its metal core is not moving

• It is a scientific mystery