Name: ____________________
Date: _____________________
Structure of the Earth
The crust is the outermost solid layer. The crust varies in thickness from
about 5km under the ocean to about 30km under the continents.
Beneath the crust is a layer called the Mantle. This is the thickest layer of
the Earth, at around 2900km. The upper part of the mantle is cooler and in
a solid state, while the bottom part is hotter and melts all the minerals, so
this part of the mantle is in a liquid state. The crust and the upper mantle
are together known as the Lithosphere.
Beneath the lithosphere, the rock of the mantle behaves like a ‘plastic’
solid. The rocks flow slowly here, and this ‘plastic’ layer is called the
Asthenosphere.
The core of the Earth is made of mostly iron and nickel. The outer core is
about 2300km thick, and it is in a liquid state due to the extremely high
temperatures. The inner core is the hottest layer of the Earth, but it is
actually solid. This layer is 1200km thick and it gives Earth its magnetic field.
Activity 1
1. Label the 4 main layers of the Earth (Outer core, crust, mantle, inner core)
Temp (oC):
20 – 500
500 – 2000
4000 – 6000
~7000
2.
3.
4.
5.
6.
7.
Which layer is the thickest? ___________________________
Which layer is the thinnest? ___________________________
On which layer do we live? ____________________________
Which layer is the hottest? ____________________________
Which layer is the coolest? ____________________________
Which layers are in a liquid state? ______________________
8. Why might the outer core be a liquid while the inner core is a solid, even
though the inner core has a higher temperature?
______________________________________________________________
______________________________________________________________
______________________________________________________________
9. Determine if the following statements are true or false:
True or False?
Every layer of the Earth is the same thickness.
The mantle is completely liquid.
The mantle is the thickest layer
We live on the crust.
The deeper we go into the Earth, the cooler it becomes.
The crust is the coolest layer of the Earth.
10. Match each of the words in the first list with the phrase that describes it
in the second list.
Mantle
We live on this layer
Crust
Layer below the crust
Inner Core
Contains melted iron and nickel
Outer Core
Layer of air
Atmosphere
Contains solid iron and nickel
Activity 2
Using the space below, create a table showing the properties of the crust,
mantle, outer core and inner core. Your headings should be Layer, Thickness,
Temperature and Composition.