L11 : Structure of Earth - Natural Phenomena, Science, Class 8 Video Lecture

hello friends this video on some natural
phenomena part 11 is brought to you by
exam vo calm no more fear from exam if
you want to know the real cause of
earthquake for that you will actually
need to understand the structure of the
earth so let us see what are the various
layers which are present inside the
earth now based on the chemical
composition the structure of the earth
is divided into four major layers that
is trust mantle outer core and inner
core so this is how it looks like so arc
as we all know it is kind of spherical
in shape so inside that sphere it is it
is a lot of things are present inside
the sphere it's like a ball so inside
the ball is not hollow instead inside
the bone you have a smaller ball inside
that you have yet another smaller ball
inside that you again have a smaller
ball so that's how you have four
different layers right so now if you
just try to so if you just try to keep
inside and see what is present inside
that ball the ball is right now bird so
you will see these four layers now in
these four layers the outermost layer is
the crust so here if you see this black
thin layer that is thrust
inside the crust you have quite a thick
layer you see this red layer it is quite
thick so this is mantle with inside this
you have the outer core this is outer
core and the innermost one is the inner
core so these are the four major layers
which are present within the earth so
the surface of the earth is basically
situated on the crust so crust is the
outermost and if you see here the black
layer is the thinnest layer so I am able
to understand this picture it is like a
ball but the ball is not hollow inside
inside the ball also you have so many
different stuffs so I have just cut a
cross section of the ball just to see
what is there inside so I am just seeing
it from one side of the ball right so if
you look at it from sideways so the
silent you would be something like this
this is Earth so if you look at it from
one side you see inside the bigger ball
which is earth you have a smaller ball
inside then you get another smaller ball
and inside you have the inner core so
this is inner core than outer food then
Bandhan and then the thin crust so that
is how the structure of the earth is now
let us see the details of each of these
layers in a little more detail so the
first is inner core so the innermost
layer as the name suggests and it is
extremely dense the density is very very
high and it is solid in nature and it is
what we made up of iron and nickel so
you will see that the core that is inner
core outer body are mostly made up of
they contain a lot of iron inside it and
that is how the magnetic field of the
earth is created because iron is a
magnetic material so magnetic field of
the earth comes out of these iron which
is present in it in the earth so this
inner core is extremely hot the
temperature of the inner pole is
approximately 5,500 degree Celsius in
fact it is more than this so the
temperature in inner core is more than
5,500 degree Celsius and sometimes it
even moves to 6,000 degree Celsius next
is the outer core outer core is also
quite dense but it is liquid so it is
kind of molten and it is also composed
of islands so the iron here is liquid
iron so here also the temperature is
quite high in somewhere around 5000
degrees Celsius but inner food is the
most hottest
so as you come outside the temperature
thing goes on decreasing the next one is
mantle samantha is fallen however
sometimes or in some areas it might be
liquid it is the thickest layer of the
earth so you saw in the picture that was
thickest layer it is composed of rocks
which are rich in iron
to magnesium so the temperature and
mantle is around 1200 degrees ashes so
you see the temperature is gradually
decreasing as we are coming towards the
outer layer and finally crust which is
the outermost layer and Trust is
relatively a thick thin layer when
compared to all other layers and in
crust also we have two types of crust
that as one is oceanic crust and the
other one is the continental crust so
what do we mean by Oceanic and
continental crust so the outermost layer
which is located below the ocean basins
that is called the oceanic crust and
oceanic crust is even thinner than
continental crust continental crust it
forms the pin it is located under the
continents so it is comparatively
cheaper so oceanic crust is thinner part
of the crust and continental crust is
the thicker part of the crust but crust
is anyway a thin layer it is not a very
thick layer when compared to mantle and
the course now the interesting part here
is so here you can see this is
interesting patterns the outer part of
the crust that is the outer part of the
sphere it is not just one single piece
if you imagine a ball so the outer
portion of the ball is like just one
piece but in this case that is not the
case instead it is made up of a number
of parts which are all joined together
to form the crust so that is how the
outer side of the crust is so we see
that the crust is fragmented that is it
is made up of separate pieces and each
piece is called a fragment and with this
it has been given a name was plate so we
say that the crust is made up of plates
now these plates play the most important
role in behind the cause of earthquakes
so here if you see this is how the here
the earth is in the form of a ball now
if you try to
magnifying how it looks like it looks
some more like this now this is not just
one single piece so this black outlines
which you see these are the plates so
seven and such claims so you see this is
one plate this is one pane
this one is one plate this is again one
plate so this is how you have so many
different claims and all of these claims
joined together it is forming the
surface of the crust thank you
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