The Earth is composed of four main layers - the crust, mantle, outer core, and inner core. The crust is the topmost layer and ranges from 7-50 km thick. It is broken into tectonic plates that move and allow heat to escape from the interior. Below the crust lies the mantle, which makes up 84% of the Earth's volume and is solid but capable of flowing. Within the mantle, convection currents transfer heat between the upper and lower regions. At the center is the core, with an outer liquid layer surrounding a solid inner core made of iron and nickel. The layers grow progressively hotter and denser toward the Earth's center.

2. LAYERS OF EARTH

3. Study inside the
earth.
Where we walk
on?

4.  Crust.
 Mantle.
 Core.

5. It is thin layer on earth’s surface.
 Crust accounts for 1% of earth’s volume.
It is made up of large amount of silicon and
aluminum.
Its depth ranges from 7-50 km .

6.  Earth crust is broken
into 19 pieces( 12
small and 7 large)
called tectonic plates.
 These plates allow
heat to escape from
interior of earth into
space.

7. • Oceaniccrust:
 Oceanic (very dense,
made of basalt).
 The crust is only about
3-5 miles (8 kilometers)
thick under the
oceans(oceanic crust).
Continental crust:
 Continental (less dense,
made of granite).
 This crust is about 25
miles (32 kilometers)
thick under the
continents
(continental crust).

8. Types of crusts

10.  It is layer between earth crust and outer core and it is 84%
of earth volume.
 It is solid but capable of flow (like hot asphalt or fudge).
 The mantle is made up of semi-molten rock called magma.
 In the upper part of mantle the rock is hard , but lower
down the rock is soft and beginning to melt.
 The hot material (magma) in the mantle rises to the top of
the mantle, cools, then sinks, reheats, and rises again.
These convection currents cause changes in the Earth’s
surface.

11. Upper mantle.
Lower mantle.

12. • The upper mantle has
olivine( a very special
rock),compounds with
silicon dioxide and
substance called
peridodite.
• Temperature ranges
between 500 to 900 C.
• The lower mantle is
more solid than upper
mantle.it has a lot
olivine rock ,iron , and
magnesium.
• Temperature in this
zone can reach up to
4000 C at boundary
with core.

13. • In geology ,the central region of earth is termed as core.
• It extends fourteen hundred to eighteen hundred miles
from earth’s center.
• The core is made of iron and nickel.
It has two parts:
• An inner solid core.
• An outer liquid core.

14. Outer core
• It consists of molten
(liquid) metal that is about
4,700°C.
• Located about 1,800 miles
beneath the crust and is
about 1,400 miles thick.
• Composed of the melted
metals nickel and iron.
Inner core
• It is solid sphere of iron.
• It is believed to be as hot as
6,650°C (12,000°F).
• Heat in the core is probably
generated by the radioactive
decay of uranium and other
elements.
• It is solid because of the
pressure from the outer core,
mantle, and crust compressing

15. Outer
core
Inner
core

16. How are the earth’s layers similar to an egg?
Shell=crust
Egg white=mantle
Yolk=core

18. Graphand table below shows the relation between depth and density/pressure, temperature
and other factors.

19. Earth quakes:
Earthquakes are caused by
tectonic movements in earth’s
crust.
Most earthquakes happen
where tectonic plates meet and
glide against each other .
Moving rock and magma within
volcanoes can also trigger
earthquakes.

21. Effects.

22. Any questions ?