The document discusses the layers of the Earth and how temperature and pressure increase with depth. It describes the three main layers - crust, mantle, and core. The crust consists of continental and oceanic crust. The mantle is divided into the lithosphere, asthenosphere, and lower mantle. The core has a solid inner core and liquid outer core. Heat in the Earth comes from primordial heat left over from formation and radioactive decay in the core, which also generates the magnetic field. Heat transfers to the surface via conduction in solids and convection in liquids like the mantle.

1. • Using data collected from seismic waves, geologists have
learned the Earth’s interior is made up of several layers.
Each layer surrounds the layer beneath it, like the layers of
an onion.

2. A JOURNEY TO THE CENTER OF THE
EARTH
• The three main layers
of Earth are the crust,
the mantle, and the
core. These layers
vary greatly in size,
composition,
temperature, and
pressure.

3. Temperature…
• About 20 meters below Earth’s surface,
rock begins to get warmer. For every 40
meters that you descend from that point,
the temperature rises 1 degree Celsius.
This rapid rise of temperature continues
for several tens of kilometers and
continues to grow hotter and hotter
approaching the core. The high
temperatures inside Earth are a result of
heat left over from the formation of the
planet.

4. Pressure…
• The more you descend into Earth’s interior, the amount
of pressure increases. Pressure results from a force
pressing on an area. Because of the weight of the rock
above, pressure inside Earth increases as you go
deeper. The deeper you go, the greater the pressure.

5. THE CRUST
• The crust is the layer
of rock that forms
Earth’s outer skin.
The crust is a layer of
solid rock that
includes both dry
land and the ocean
floor. This layer of
the Earth is much
thinner than the
layers beneath it.

6. • The crust beneath the ocean is called
oceanic crust, which consists mostly of
rocks such as basalt. Basalt is dark rock
with a fine texture.
BASALT

7. • Continental crust, crust that forms the
continents, consists mainly of rocks such as
granite. Granite is a rock that usually is light in
color and has a coarse texture.
GRANITE

8. THE MANTLE
• Below Earth’s crust is the mantle. Earth’s mantle is
made up of rock that is very hot, but solid. Scientists
divide the mantle into layers based on the physical
characteristics of those layers. Overall, the mantle is
nearly 3000 km thick.

9. The Lithosphere…
• The upper most part of the mantle and the crust
together form a rigid layer called the
lithosphere. In Greek, “lithos” means “rock.”

10. The Asthenosphere…
• Below the lithosphere is a layer that is
hotter and under increasing pressure.
Like road tar is softened by the heat
of the sun, this part of the mantle is
somewhat soft- it can bend like
plastic. This soft layer of the mantle
is called the asthenosphere. In
Greek, “asthenes” means “weak.”
Although this layer is softer than the
rest of the mantle, it is still solid.

11. The Lower Mantle…
• Below the asthenosphere, the mantle is
solid. This solid material extends all the way
to Earth’s core.

12. THE CORE
• Beneath the mantle is
Earth’s core. The
core is made mostly
of the metals iron and
nickel. It consist of
two parts- a liquid
outer core and solid
inner core.

13. The Inner and Outer Cores…
• The outer core is a
layer of molten
metal that
surrounds the inner
core. Despite
pressure from the
rock above, it is
liquid.

14. • The inner core is a dense ball of solid metal. In the inner
core, extreme pressure squeezes the atoms of iron and
nickel so much that they cannot spread out and become
liquid.

15. The Core and Earth’s Magnetic
Field…
• Scientists believe that
movements in the Earth’s
liquid outer core create
Earth’s magnetic field.
Because Earth has a
magnetic field, the planet
acts as a giant bar
magnet.

16. THE
EARTH’S
INTERNAL
HEAT

17. INTRODUCTION
• Heat is needed for organisms to
survive. This heat may come from
internal and external sources. The
Earth's internal heat provides the
heat and energy which supplies
the force for natural phenomena
such as earthquakes and volcanic
eruptions. It also provides energy
for the movement of the plates.
However, despite the large amount
of heat that the Earth possesses, its
internal energy is greater during its
early stages.

18. SOURCES
OF
EARTH’S
INTERNAL
HEAT
1. Primordial heat of
the planet remains
from its early stage.
2. Radiogenic Heat or
Heat from the decay of
radioactive elements.

19. Primordial Heat
Is the internal heat energy accumulated by dissipation
in a planet during its first few million years of
evolution.

20. Primordial Heat

21. Primordial Heat

22. Primordial Heat

23. Radiogenic Heat
Is the thermal energy released as a result of spontaneous
nuclear disintegration of natural radioactive elements
inside the planet: uranium, thorium, and potassium.

24. Decay of Long-
lived Radioisotopes

25. Decay of Long-
lived Radioisotopes

26. Decay of Long-
lived Radioisotopes

27. Methods
of Heat
Transfer
•Conduction
•Convection
•Radiation

28. Methods of
Heat Transfer
Conduction –
governs the
thermal conditions
in almost entire
solid portions of
the Earth.

29. CONDUCTION
can be defined as the
process by which heat
energy is transmitted
through collisions
between neighboring
atoms or molecules.

30. Heat from the Earth's
core and radiation
from the Sun is
transferred to the
surface of the Earth by
conduction.
CONDUCTION

31. Methods of
Heat Transfer
Convection –
dominates the thermal
conditions in the zones
where large quantities
of fluids(molten rocks)
exist.

32. CONVECTION
In geological time scale,
the mantle behaves as a
viscous fluid
due to the existence of
high temperatures.

33. CONVECTION
In convection current, the
mantle of the
earth moves slowly because
of transfer of heat from the
interior of the earth up to
the surface. This result to the
movement of tectonic plates.

34. CONVECTION
Hot materials are added at
the edges of a plate and then
it cools. At those edges, it
becomes dense by its
exposure from the heat and
sinks into the earth at an
ocean trench. This start the
formation of volcanoes.

35. Distribution
of Earth’s
Internal
Heat

36. Methods of
Heat Transfer
Radiation –
the process of
heat exchange
between the
Sun and Earth

37. RADIATION
process by which
heat is directly
transmitted through
a substance when
there is a difference
of temperature or
between adjoining
regions, without
movement of the
material.

38. REMEMBER
•Heat of the planet is a
factor to make the planet
habitable.
•Primordial and
Radiogenic heat are the
main sources of heat of
the Earth
•Heat Transfer Processes:
Conduction, Convection,
and Radiation