for elementary.. :)

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.