Transcript Layers of the Earth

Layers of the Earth
Geosphere
The Earth as a System
• Integrated system of rock, air, water, and
living things.
• This system is divided into four parts:
–
–
–
–
atmosphere (air)
hydrosphere (water)
biosphere (living things)
geosphere (rock)
Geosphere
• Solid part of the
Earth’s crust that
consists of all
rock, and the soils
and sediments on
Earth’s surface.
• Most located in
Earth’s interior
Earth’s Interior
• Seismic Waves: the
waves that travel
through the Earth’s
interior during an
earthquake.
• Altered by the type of
material that it travels
through.
Seismologists
• Scientists who
measure changes in
these waves to
determine that the
earth’s interior is
made in layers.
Composition of the Earth
• Three layers:
– crust
– mantle
– core
• Density increases
towards the center of
the Earth
Crust
• Thin, outer layer.
• Made up of light
elements
• less than 1% of
Earth’s mass
• 5-70km thick
Mantle
• Layer beneath the
crust
• 64% of mass of Earth
• 2,900 km thick
• Made of
– lithosphere
– asthenosphere
– mesosphere
Lithosphere
• Outer layer
• cool, rigid
• divided up into
huge tectonic
plates
Asthenosphere
• 250 km thick
• solid, plastic layer
made of rock
• flows very slowly
and allows
tectonic plates to
move across
Mesosphere
• 2,250 km thick
• “middle” sphere
• lower part of mantle
Core
• 3,248 km radius
• sphere of hot, dense
nickel and iron
• 4,000 - 5,000 °C
• 1/3 of the Earth’s mass
• Made of
– Outer Core
– Inner Core
• Outer Core; 2,200 km
thick, outer shell,
made of liquid nickel
and iron
• Inner Core: 1,228 km
radius; a sphere of
solid iron and nickel
First Life???
• First life may have first evolved deep in the
crust and then migrated to the surface when
conditions became favorable.
• “extremophiles”
• Hypothesized that the biomass below the
surface far exceeds the biomass at the
surface.
• Be able to draw and label the three layers of
the earth (crust, mantle, and core) as well as
the 5 layers based on physical properties
(lithosphere, asthenosphere, mesosphere,
outer and inner core).