Transcript Inside the Earth

Andes Mountains,
South America
Evidence of Continental Drift
.
– Fossils of Glossopteris, a seed fern that resembled low
shrubs, have been found on many continents, indicating
that the areas had a single climate that was close to the
equator.
Earth’s Layers
Layers of the Earth
• There are two ways that scientists label
the layers of the Earth.
– Composition layers
– Physical layers
Composition (What it is made of)
• Crust
• Mantle
• Core
Earth’s Layers
• How are the earth’s
layers similar to an
egg?
• Shell=crust
• Egg white=mantle
• Yolk=core
The Crust
•
•
•
•
Outer layer
5-100 km thick
Thinnest layer
2 types of crust
– Oceanic (very dense,
made of basalt)
– Continental (less
dense, made of
granite)
Oceanic and Continental Crust
• Middle layer
• Very thick layer
• Roughly 2800 km
thick
• No one has ever
drilled to the mantle
• It is VERY hot
• composed of silicate
rocks that are rich in
iron and magnesium
• Even though its solid
it can flow
The Mantle
Convection Currents
Convection Currents
Cause the Tectonic
Plates to move
Movement of these
plates Cause:
1. Earth Quakes
2. Mountains
3. Volcanoes
4. Rift valleys
5. Tsunamis
Tectonic Plates
• Earth’s crust is broken into about 19
pieces
• These plates move on top of the
asthenosphere
• Made mostly of Iron
and Nickel
• 1/3 of the earth’s mass
• Very hot
• The core’s diameter is
about the size of Mars
(6856 km )
The Core
Physical Layers
• The less familiar layers are the physical layers.
• They are based on how the layer looks or acts.
Physical Structure of the Earth
• Lithosphere (Crust) - (15-300 km) rigid outer layer
• The tectonic Plates
• A combination of crust and the upper region of
the mantle
• Cold and brittle (easily broken)
Physical Layers
• Asthenosphere
• weak sphere” (250 km)
– Hard rock that acts
like warm tar or
honey
– Ductile and highly
Viscous
• involved in plate
tectonic movements
Mesosphere
• Layer found
between the
asthenosphere
and the outer
core
Physical Layers Continued
• Outer Core- (2200 km)
– liquid layer
• Inner Core- (diameter= 2456 km)
• Solid, dense core of the planet
• Densest layer of the planet
Side by side comparison
Crust
Mantle
Core
Lithosphere
Asthenosphere
Outer Core
Inner Core
The “spheres”
• Atmosphere
–
–
–
–
Least dense layer of the Earth
Made of mostly oxygen and nitrogen
Surrounds the Earth
Filters out harmful radiation
• Biosphere
– Layer that all life is in
– Not a specific location, just anywhere life is
found
Hydrosphere
– Density= ~1.0 g/mL
• Describes the combined
mass of water found on,
under, and over the
surface of a planet.
• Approximately 75% of the
Earth's surface, an area of
some 361 million square
kilometres (is covered by
ocean.
Interesting fact…
• Did you know?...
– The center of the Earth’s core is hotter than
the surface of the sun. The temperature of
Earth’s inner core reaches 6000 °C whereas
the surface of the sun is roughly 5500 °C.
• The sun’s core, however, is 15,000,000 °C