The Earth is made up of concentric layers, with the crust being the outermost layer. Below the crust lies the mantle, which extends almost 3000 km deep. The innermost layer is the core, with a radius of 3500 km. The crust varies in thickness depending on whether it is over continental masses or ocean floors. Continental crust consists of silica and alumina, called sial, while oceanic crust contains silica and magnesium, called sima. The Earth's crust contains various types of rocks that form through igneous, sedimentary and metamorphic processes and undergo continuous changes through the rock cycle.

1. Inside Our Earth
Class- VIII
Presented by
Gourab Narayan Deb
B.Ed , 4th Semester
KSS Jain College of Education

2. About The Earth
• The Earth, our
homeland is a dynamic
planet.
• It is constantly
undergoing changes
inside and outside.

3. Interior Of The Earth
•Concentric layers with one inside another
•Three layers- Crust,Mantle,Core

4. Crust -
•The uppermost layer
•Thinnest layer
•35 km on the
continental masses
•5 km on the ocean
floors

5. Mantle –
•Situated just beneath the crust
•Extends up to 2900 km
Core –
•Innermost layer
•Radius of about 3500 km
•Nife
•Very high temperature & pressure

6. • Continental masses
are consist of Silica
& Alumina
• It is thus called sial
• Oceanic crust consist
of Silica &
Magnesium
• It is called sima
Sial & Sima

7. Rocks & Minerals
•Earth’s crust consists of
various types of rocks
•Have different colour,
size and texture
•Three major types of
rocks- Igneous,
Sedimentary,
Metamorphic rocks

8. Igneous Rocks
•Primary rocks
•Becomes solid when
molten magma cools
•Two types
-Intrusive rocks
-Extrusive rocks
•Granite is an example
of such a rock

9. Sedimentary Rocks
•Large rocks broken down
into small fragments
•Smaller particles are
called Sediments
•Sandstone is an example
•Contain fossil of plants ,
animals

10. Metamorphic Rocks
•Igneous &
Sedimentary rocks
can change into it.
•Due to great heat
and pressure
•Clay changes into
slate

11. Rock Cycle
•One type of rock
changes into
another type
•Process occurred
in a cyclic manner
•Known as the rock
cycle

12. Thank You