Earth's Layers

Earth's Layers

Features of Earth's Layers

• Today we know that Earth's interior is made up of three main parts:

• The crust, mantle, & core

• Each layer varies greatly in size, composition, temperature and pressure

Pressure

The deeper inside Earth, the greater the mass of rock that is pressing down from above. This creates pressure. The deeper down inside the Earth, the greater the pressure is.

Temperature

The temperature inside Earth increases as depth increases. The intense pressures squeeze rocks together and release energy from radioactive substances.

Open Ended

Name one of Earth's layers

The Crust

• Outermost and thinnest layer of Earth

• 2 types of crust: Oceanic (under the ocean) and Continental (land)

• Composed mostly of oxygen, silicone, and aluminum

The Crust

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

• Can be as thick as 80 km thick under mountains and very thin under oceans

Multiple Choice

How many types of crust are there?

• 2

• 3

• 4

• 5

Multiple Choice

As we travel deeper into Earth, the temperature_______.

• increases

• goes up and down

• decreases

• stays the same

Multiple Choice

Both the temperature and pressure increase as depth increases.

• True

• False

Oceanic Crust

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

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

• More dense and thinner than continental crust (5-10km)

• Younger (newer) than continental crust

Continental Crust

• Continental crust is what forms all of Earths land masses

• The composition varies, depending on the location

• Overall, it is mostly types of granite

Continental Crust

• Less dense than oceanic crust

• Thicker than oceanic crust

• Older than oceanic crust

Multiple Choice

What is the HARD, RIGID outer layer of Earth called?

• asthenosphere

• crust

• lithosphere

• mantle

The Lithosphere

• Solid outer section of Earth, which includes the crust (rocky layer)

• Also includes the cool, dense, rigid upper part of the mantle

• Averages about 100km thick

Asthenosphere

• A soft layer beneath the lithosphere

• Material is hotter and under higher pressure

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

Asthenosphere

• A soft layer beneath the lithosphere

• Material is hotter and under higher pressure

• Weaker, less rigid (plasticity - like silly putty)

• Crust moves over this layer

The Mantle

• Largest layer of the Earth

• It is nearly 3,000 km thick

• Composed of silicate rocks rich in magnesium and iron

• Intense heat causes the rocks to rise and then cool and sink. 

• The process is called convection, which causes the crust to move.

• Average temperature 3000 degrees

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 the largest layer of Earth?

• crust

• inner core

• mantle

• outer core

Multiple Choice

Name the soft, pliable layer directly below the lithosphere.

• lower mantle

• crust

• outer core

• asthenosphere

The Core

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

• Consists of 2 layers: the outer core and the inner core

• Total radius = 3,480 km thick

Outer Core

• A layer of molten metal surrounding the inner core

• The intense heat causes the metals to melt, making this layer a liquid (Iron and Nickel)

• 2,258 km thick (second largest)

• Average temperature 4000 -5000 degrees

Inner Core

• A dense ball of solid metal

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

• 1,222 km thick

• So hot it melts everything in the outer core

• Spins at a speed faster than the earth rotates

• Most dense layer of Earth

• •Average temperature 5000 -6000 degrees

The Core and Earth's magnetic Field

• Scientist believe that the movement inside the liquid outer core create the magnetic field around the Earth

Multiple Choice

What is the only liquid layer of Earth?

• crust

• outer core

• mantle

• inner core

Seismic Waves

• Waves of energy cause by earthquakes and other rock movement

• Travel through some layers of the Earth

• Recorded using seismographs

Seismic Waves

• Seismic Waves are used to determine which layers of the Earth are solid or liquid

• Some seismic waves cannot pass through certain layers, giving us a clue to the layers' composition

Multiple Choice

What are the four layers of Earth from inside to outside?

• Crust, Outer core, mantle, inner core

• crust, mantle, outer core, inner core

• Inner core, outer core, mantle, crust

• Mantle, outer core, inner core, crust

Multiple Choice

The _____ is a solid metal ball.

• crust

• outer core

• mantle

• inner core