Download EARTH`S INTERIOR

EARTH’S INTERIOR
Name _______________________________________________ Hour _____
The Layers of the Earth
The earth is made up of four different layers. If you are wondering why it
has that many layers this is because of its history. There are many historians
and geologists that believe the earth wasn’t always made up for four layers.
Instead, they believe that as the earth cooled rapidly, the heavier parts of
the earth sank inside of the world and the lighter, more dense materials
moved into the middle of the world. Therefore, the lightest materials of all
rose to the top. This explains why things like rock are on the surface of the
earth and the much heavier things like iron are located in the earth’s core.
The four layers of the earth are:

The Crust – the part of the earth that you live on

The Mantle – a hot area that has the ability to flow (think of lava)

The Outer Core – the heaviest parts of earth in a hot liquid state

The Inner Core – the heaviest parts of earth in a solid state
Based on the reading above, label the 4 layers of the earth below.
The crust of the earth is about 5 miles thick under oceanic crust and 25 miles thick under the
continental crust. This means that under water (oceans) the layer of the earth goes five miles and
under solid ground it goes further at twenty-five miles. The crust is broken into many different
parts called plates. These plates are located below the actual crust on a soft area known as a
mantle. The plates float on the mantle which allows them to move. The crust of the earth is made
of rock.
The Mantle is the largest layer of the earth at 1,800 miles thick. It is made up of extremely hot
rock. The plates under the crust of the earth move because the mantle moves. The mantle is so
dense that the plates drift along on top similar to how oil might float on top of water. Some
scientists believe the flowing occurs due to convection currents. Convection currents are
caused by hot material in the bottom of the mantle rising up, cooling, and sinking to the bottom
again. As it gets to the bottom it again becomes hot and repeats the process continually. This
current is able to move the plates of the crust as well.
The top of the outer core is 4,000 degrees Fahrenheit but the deeper you go into the core, the
hotter it will become. At its hottest point the outer core will reach a temperature of 9,000 degrees
Fahrenheit. This layer of the earth is so hot that the entire layer is layer of liquids. The outer core is
a total of 1,400 miles thick and 1,800 miles beneath the top layer of the crust. This area of the earth
is comprised specifically of melted nickel and iron.
The inner core is the final layer of the earth. This layer of the earth has a temperature so high
that metals are put together and cannot move like liquid does but instead they vibrate and work as
a solid. The inner core can be found 4,000 miles under the crust. This layer of the earth is
approximately 800 miles thick. The highest temperature for this layer will be found in the deepest
section of the layer and will reach 9,000 degrees. The pressure for this layer is an amazing
45,000,000 pounds for square inch. To get a better understanding of what that means it is
3,000,000 times more than the air pressure you are used to.
Questions:
1. How many layers of the earth are there? ___________
2. What is the highest temperature level reached on the earth’s core? ______________
True or False
3.
4.
5.
6.
The outer core is all liquid gases. __________
The Inner Core is between the Mantle and the Crust. _________
The plates under the crust are able to move because the mantle is made of liquid. _____
Convections currents move the plates of the earth. _______