Transcript Earth`s Interior Notes

Earth’s Interior
Link for intro animation:
http://www.precisiongraphics.com/portfolio/animation/
Earth began to form in a process called accretion
(gathering), where dust and debris collide and stick
together to form a large mass.
Eventually the mass got large enough to be called a
Planetesimal (planet building block)
The planetesimal began to cool as it spun through space.
Oblate spheroid forms- The spinning motion of the
young, developing Earth caused it to form into a
sphere that bulges in the center.
7900
miles
7926 miles
How do we know about Earth’s
Interior?
1. Drilling
2.Earth’s
Magnetic
Field
3.Seismic
Waves
Drilling into the
Earth
•Humans have been
able to drill down about
12 km (approximately
7.6 miles) into the
Earth’s crust.
•We have never drilled
into the mantle, outer
core, or inner core.
Why are there different layers?
• Earth’s main heat engine: 1. radioactive
decay (Uranium, Potassium, Thorium). 2.
Pressure from asteroid hits.
• Differentiation (layering) of Earth’s interior
is due to gravity and differing densities.
Earth’s 4 Layers
1.
2.
3.
4.
Crust
Mantle
Outer core
Inner core
Crust
• Solid, rigid layer
mostly Oxygen &
Silicon (SiO2).
• Depth of 7-70 km.
• Two types:
Oceanic and
Continental
Earth’s Crust
Mantle
• Plastic-like with liquid
properties
• Composed mostly of
iron, silicon, and
magnesium
• Depth of 2890 km
(from the surface)
• 1000 °C
Thickest of Earth’s Layers!
Earth’s Mantle
Outer Core
• Liquid
• Composed of iron
and nickel
• Depth of 5150 km
(from the surface)
• 3700 °C
Earth’s Outer Core
Inner Core
• Solid
• Composed of
iron and nickel
• Extends to a
depth of 6371
km (from the
surface)
• 4300 °C
Ooblek
• Observations -Write observations and
conclusion in booklets titled Ooblek:
• Before the addition of water, is cornstarch a
solid, liquid, or gas?
• When you try to pour the mixture into your
hand, does the mixture behave like a solid,
liquid, or gas? Explain
• When you try to roll the mixture into a ball
and apply pressure, does the mixture act like
a solid, liquid , or gas? Explain
• Conclusion:
Earth’s Inner Core
How the Earth Moves
Lithosphere-Made up of the crust and the
uppermost portion of the mantle.
Asthenosphere-Plastic-like and made up of the
upper mantle.
Movement of the liquid outer core of the Earth
generates a strong magnetic field that surrounds
the planet. This causes the Earth to act much like
a large magnet, with the poles of the magnet
located near the poles of the Earth.
Earth’s Magnetic Field
Our magnetic field is called the magnetosphere. It stretches
out through the atmosphere and acts as a protective barrier
to deadly, high-energy solar radiation.
Earth’s Magnetic Field
The Earth’s magnetic
field allows us to use
compasses to locate
direction on the planet.
A small magnetic
needle that is allowed
to spin freely aligns
itself with the Earth’s
magnetic field and
points to the magnetic
North Pole.
The point of origin of an earthquake is called
the Focus. The spot on the surface of the
Earth directly above it is called the Epicenter.
Seismic wave: the energy
released during an
earthquake which travels
through the Earth.
3 Types:
* Primary (P) waves
* Secondary (S) waves
* Surface waves
Seismic Waves
Features 1. How
2.
do they Where
occur? do they
start?
3. Can
they
travel
through
solids?
Categories
Primary
Wave
(P-Wave)
Secondary
Wave
(S-Wave)
4. Can
they
travel
through
liquids?
5. Can
they
travel
through
gasses?
6. How do
they react
when
density
changes?
7. Are
they
detected
on the
other
side of
the
world?
8. Do
they
show up
in
Shadow
Zones?
9. Can
they
travel
through
the
inner
core?
10. Can
they
travel
through
the
outer
core?
Primary Waves
Primary waves, also
known as P-waves,
1.
Travel through the
Earth by
compressing and
expanding.
2.
Can travel through
solids, liquids, and
gases.
3.
Are the fastest type
of seismic wave,
they are always
detected first by a
seismograph.
Secondary
Waves
Secondary waves,
also known as Swaves.
1.
Travel in an upand-down pattern
much like the
waves that move
through water.
2.
Move much more
slowly than Pwaves
3.
Can only travel
through solid
material, not liquids
and gases.
Surface Waves
Surface waves are
produced as a rolling
motion of ground
along the surface of
the Earth.
Surface waves are
the most destructive
of all seismic waves.
Waves Tell Us Earth’s Composition.
Remember:
• P-waves can travel
through solids, liquids, and
gases, while S-waves can
only travel through solids.
•We noticed that P-waves
pass through the entire
Earth, while S-waves can
disappear.
•So we know what Earth’s
layers are made of !!!
Seismic Waves
Data from many
earthquakes has shown
that S-waves disappear
when they encounter the
liquid outer core.
As P waves pass from one
type of material into
another, they are refracted
(or bent slightly).