Presentation #1 for the Biology L2 project

1. Juan Sebastián Rodríguez Cubillos
Biology L2 project
9-A
Earth´s inner and outer core
Presentation #1

2. Earth's inner core (Introduction):
• Is Earth's innermost part and is a
primarily solid ball with a radius of about
1,220 km (760 mi), according to seismological
studies. (This is about 70% of the Moon's
radius.)

3. Composition:
• The materials that the inner core has can be
represented in simple percentages (these
values are approximations):
• Iron 80%
• Nickel 12%
• Sulfur, oxygen, gold, platinum and siderophile
elements 8%

4. Discover:
• Earth was discovered to have a solid inner
core distinct from its liquid outer core in 1936,
by the seismologist Inge Lehmann, who
deduced its presence from observations of
earthquake-generated seismic waves that
reflect off the boundary of the inner core and
can be detected by sensitive seismographs on
the Earth's surface.

5. Temperature and pressure:
• The temperature of the inner core can be
estimated by considering both the theoretical
and the experimentally demonstrated constraints
on the melting temperature of impure iron at the
pressure which iron is under at the boundary of
the inner core, temperature is about 5,700 K
(5,430 °C; 9,800 °F).
• Meanwhile the pressure consists of 330 to 360
gigapascals.

7. Outer core (Introduction):
• is a liquid layer about 2,266 km (1,408 mi)
thick composed of iron and nickel that lies
above Earth's solid inner core and below
its mantle.

8. Composition:
• As the inner core the outer core materials can
be also represented in percentages (these
values are approximations):
• Iron 49%
• Nickel 49%
• Other light elements 2%

9. Properties:
• Temperature: The temperature of the outer
core ranges from 4400 °C (8000 °F) in the
outer regions to 6100 °C (11000 °F) near the
inner core.
• Importance: Without the outer core, life on
Earth would be very different. Convection of
liquid metals in the outer core creates
the Earth's magnetic field.

10. Magnetic field:
• Is the magnetic field that extends from
the Earth's interior to where it meets the solar
wind, a stream of charged particles emanating
from the Sun.

11. Importance of the magnetic field:
• Earth's magnetic field serves to deflect most
of the solar wind, whose charged particles
would otherwise strip away the ozone layer
that protects the Earth from harmful
ultraviolet radiation. One stripping mechanism
is for gas to be caught in bubbles of magnetic
field, which are ripped off by solar winds.