Download Earth`s Interior Notes

Earth’s Interior
Chapter 8, pages 233-237
Link for intro animation:
http://www.precisiongraphics.com/portfolio/animation/
Earth’s Formation
- 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 caused Earth to form into a sphere
bulging in the center.
7900
miles
7926 miles
Why does Earth have different layers?
- Differentiation (layering) of Earth’s interior is
due to gravity and differing densities in
molten state.
- Earth’s main heat engine to create molten
state : 1. radioactive decay (Uranium, Potassium,
Thorium). 2. Pressure from asteroid collisions.
Earth’s 4 Layers
1.
2.
3.
4.
Crust
Mantle
Outer core
Inner core
1. Crust
- Solid, rigid layer mostly
Oxygen & Silicon (SiO2).
- Depth of 7-70 km.
- Two types: Oceanic and
Continental
Earth’s Crust
2.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
3. Outer
Core
- Liquid
- Composed of iron and
nickel
- Depth of 5150 km (from
the surface)
- 3700 °C
4. Inner Core
- Solid
- Composed of
iron and nickel
- Extends to a
depth of 6371
km (from the
surface)
- 4300 °C
Earth’s Inner Core
How the Earth Moves
- Lithosphere is made up of the crust and the
uppermost portion of the mantle and is solid.
- Asthenosphere is made up of the upper mantle
and is “plastic-like”.
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: How does ooblek model the Earth’s outer
core and inner core?
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.
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?
Seismic (Earthquake) Wave Basics
- Seismic wave: the energy released during an
earthquake which travels through the Earth.
-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.
3 Types of Seismic Waves:
* Primary (P) waves
* Secondary (S) waves
* Surface waves
Primary Waves
1. Primary waves, also
known as P-waves,
- Travel through the Earth
by compressing and
expanding.
- Can travel through
solids, liquids, and
gases.
- Fastest seismic wave.
Secondary
Waves
2. Secondary waves,
also known as Swaves.
- Travel in an up-anddown pattern much like
the waves that move
through water.
- Can only travel
through solid material,
not liquids and gases.
Surface Waves
3. Surface waves
- produced as a
rolling motion of
ground along the
surface of the
Earth.
- Surface waves are
the most
destructive.
Waves Tell Us Earth’s Composition.
- Scientists noticed that
P-waves pass through
the entire Earth, while
S-waves can disappear.
Shadow Zones
- 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).
Magnetosphere
- Movement of the liquid outer core of the Earth
generates a strong magnetic field that
surrounds the planet.
- The poles of the magnet are located near the
poles of the Earth.
Why is the Magnetosphere
important?
- It stretches out through the atmosphere and acts as a
protective barrier to deadly, high-energy solar radiation.
- Creates brilliant light shows called auroras.
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.