The Earth is composed of several layers, including a crust, mantle, and core. The crust is the outermost solid rock layer that continents and oceans reside on. Below is the mantle, made of both solid and molten rock. At the center is an iron-nickel core, with the outer core liquid and the inner core solid. Seismographs are used to study the composition and structure of Earth's internal layers.

2. • The Earth is a planet that is almost
spherical in shape and is made up of LAND,
WATER, AND AIR.
• Large masses of land, called CONTINENTS,
comprise about one-fourth of its surface.
• 75% of it is covered with water.
• The blanket of air surrounding Earth is
called ATMOSPHERE.

3. LAYERS OF THE EARTH
 The outermost layer of the
Earth is the CRUST.
 Made up of loose solid
rocks where continents
and oceans are located.
 The thickness of the
continents and oceans
varies from 10-65 km.
crust

4. 2ND LAYER OF THE EARTH
• MANTLE which is 2,880 km
thick.
• It is composed of solid rocks
in the upper portion while,
very hot molten rocks in its
lower portion.
• The boundary between crust
and mantle was discovered by
ANDRIZA MOHOROVICIC.
• The boundary named as the
MOHOROVICIC
DISCONTINUITY or MOHO,
varies from place to place.

5. 3RD LAYER OF THE EARTH
• The CORE is divided into
two parts:
• OUTER CORE and INNER
CORE.
• Outer core is about 2880-
4960 km thick.
• It is composed of molten
iron and nickel. Studies of
earthquake waves suggest
that the outer core is made
up of liquid(molten
metals).

6. INNER CORE
 INNER CORE is believed
to be made up of solid
materials.
 It has a diameter of about
2560-2880 km.
 The entire core has an
approximate temperature
of 4700°C.

7. SEISMOGRAPH
 An instrument that
measures the forces and
direction of earthquake
waves.
 The density of the layers
was suggested by the
study of earthquake
waves.
 The center of the Earth is
known to be very hot
because of the magma
released from volcanoes.

8. SCIENCE IDEAS
• The layers of the Earth are the CRUST, the MANTLE, and the
CORE.
• The CRUST is the outermost layer of the Earth.
• The MANTLE, which lies beneath the crust, is composed of solid
rock and hot molten rock.
• The CORE, is made up of molten iron, nickel in its outer portion
and solid materials in its inner structure.
• The layers of the solid Earth is being studied using modern
instruments like the SEISMOGRAPH.