Layers of the Earth and Density

Unit 4 Lesson 1

Earth's Layers

By the end of this lesson, you should be able to identify Earth's compositional and physical layers and describe their properties.

What are Earth's layers?

Multiple Choice

True or False: The outermost layer of solid Earth is sometimes called the crust.

• True

• False

Multiple Choice

True or False: The crust is the densest layer.

• True

• False

Multiple Choice

True or False: The mantle is the layer between the crust and the core.

• True

• False

Multiple Choice

True or False: Earth's core is divided into five parts.

• True

• False

First, lets review density

Multiple Choice

If an object is less dense than the liquid it is in, will it sink or float?

• 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

What is the Earth made of?

●Earth is composed of three compositional
layers: Crust, Mantle, Core

○Compositional Layers: structural layers of the
Earth defined by the materials from which
they are made, each with their own densities.

●Earth is composed of five physical
layers: Lithosphere, Asthenosphere,
Mesosphere, Outer Core, and Inner Core

○Physical layers: structural layers of Earth
defined on the basis of how materials act

●Each layer of the Earth is made up of different elements

○The solid portion of Earth is made of mostly Oxygen (O) and Silicon (Si)

○The atmosphere is made mostly of Nitrogen (N) and Oxygen (O)

●Each layer of the Earth has a different density and temperature

Crust

●The outermost layer of the Earth

●Two types of crust: continental and
oceanic

●Thinnest Layer

●Solid Layer

●Life exists on this layer

●Composed of mainly oxygen (O),
silicon (Si), and aluminum (Al)

Multiple Choice

Which is NOT true about the Crust?

• It is the outermost layer of the Earth

• It is the thickest layer

• Life exists on this layer

• It is a solid layer

Mantle

●Between the outer core and the crust

●Thickest layer

●Semi-solid: having the qualities of
both a solid and a liquid;
exceptionally thick substance
○Like jello or oobleck

●About 500 to 4,000 degrees Celsius

●Composed of mainly magnesium (Mg)
and iron (Fe)

Multiple Choice

The mantle is a ______: which is having the qualities of both a solid and a liquid; exceptionally thick substance.

• Solid

• Semi-solid

• Liquid

• Gas

Outer Core

●Surrounds the inner core

●Liquid metal

●Composed of molten (liquid) iron
(Fe) and nickel (Ni)

●Temperature ranges from 4,000 to
5,000 degrees Celsius

Multiple Select

What 2 metals is the molten in the outer core made up of?

• iron (Fe)

• nickel (Ni)

• hydrogen (H)

• helium (He)

Inner Core

●Inner most layer of the Earth

●Solid because of extreme pressure

●Composed mostly of iron (Fe)

●Hottest layer; about 6000 degrees
Celsius

Multiple Choice

About how hot is the Inner Core?

• 5,000 degrees Celsius

• 6,000 degrees Celsius

• 600 degrees Celsius

• 1,000,000 degrees Celsius

Reorder

Reorder the following from least dense (left) to most dense (right).

• crust

• mantle

• core

1

2

3

• 1
• 2
• 3

The other layers…

●Lithosphere: the solid, rigid outer layer of
the Earth consisting of the crust and the
solid portion of the upper mantle

●Asthenosphere: the somewhat fluid
portion of the mantle upon which the
lithosphere is located

●Mesosphere: the region of the mantle
beneath the lithosphere and
asthenosphere, but above the outer core

Draw

Label the 4 main layers of the Earth with the following letters:

A- Inner Core B- Outer Core C- Mantle D- Crust

​Lithosphere

• ​The lithosphere is the top, solid section of the Earth.

• It is made up by the crust and upper mantle.

• ​It forms the tectonic plates

​Asthenosphere

• ​Weak soft mantle

• Rock flows more slowly

• Tectonic Plates move on this layer

​Mesosphere

• ​Strong Lower Portion of the Mantle

• Rock flows more slowly than rock in the asthenosphere

Let's Review

Multiple Choice

The _______ is a region of hot, slow-flowing, solid rock between the core and the crust.

• core

• mantle

• crust

• atmosphere

Multiple Choice

The __________ is the densest compositional layer and makes up one-third of Earth's mass.

• core

• mantle

• crust

• atmosphere

Multiple Choice

The __________ is the outermost, rigid physical layer of Earth.

• Lithosphere

• Asthenosphere

• Mesosphere

• Inner Core

• Outer Core

Multiple Choice

Which model of Earth's interior has three parts; the crust, mantle, and core?

• Earth's Compositional Layers

• Earth's Physical Layers

Multiple Choice

Which of Earth's compositional layers is made up mostly of iron and nickel?

• Crust

• Mantle

• Core

Open Ended

Explain the difference between the lithosphere and the crust.

Open Ended

Explain the differences between the inner core and the outer core.