Download Earth`s Layers

Earth’s Layers
Exploring Earth’s Interior (Article)
Do we have much info on the Earth’s Interior?
How did the author use the following as analogies in
the reading?
Ford cars & World Series
Brick traveling 45 minutes
An apple’s skin
Coal miner
Sidewalk in New York city & strand of spaghetti
How do we know the different layers exist?
Earth’s Layers (Article)
Provide at least one fact about each layer of the
Earth.
What is the lithosphere & asthenosphere?
Earth’s layers  Divided 2 different ways:
1. Based on composition
2. Based on physical properties
Three layers based
on composition:
1) Crust
2) Mantle
3) Core
Note: Denser material collects
in the core because denser
objects always sink due to
gravity.
A. Makes up 1/3 of the
Earth’s mass
B. Mostly Fe & Ni (the
denser elements)
A. Between the core and crust
B. Most of the Earth’s mass is in
the mantle
C. Made of Si, O, Fe & Mg Contains more Mg, which is
denser than Al in the crust
D. Temperature = 870oC –
2200oC
The top layers of the mantle are hot enough to be
plastic or semi-liquid, which allows it to…
FLOW
• Thin, solid, outer most layer,
up to 870oC - increasing with
depth
Continental
Crust
Oceanic Crust
Continental Crust
Oceanic crust 
Often composed of granite; mostly Al,
Si, O, Ca, Na, K; thick & less dense
Usually composed of basalt; mostly Si, O, Fe, Mg;
thin & more dense
Why does oceanic crust sit lower than continental crust?
- Basalt is more dense than rocks in continental crust.
Five layers based on
physical properties:
1) Lithosphere
2) Asthenosphere
3) Mesosphere
4) Outer core
5) Inner core
Lithosphere •
2 parts: rocky crust and rigid, outermost
mantle
Asthenosphere  •
Mesosphere •
Plastic (flowing) upper mantle
directly beneath the lithosphere
Dense, hard lower layers of the mantle
Outer Core
•
molten Fe & Ni – produces
Earth’s magnetic field
Surrounds Inner Core
Temperature = 2200-5000C
Less pressure than inner core
•
•
•
Inner Core
•
•
•
Solid Fe & Ni
Temperature = 5000oC
Extreme pressure
Why do you think part of the core is
liquid, when the inner core is solid?
The intense pressure at the center of the
Earth squeezes it into a solid!
When earthquakes occur,
seismic waves
(vibrations) are sent out
in all directions, through
the earth.
These vibrations reach
different places at
different times because
of the ways the waves…
BEND and CHANGE SPEED
as they pass through
Earth’s layers.
Journey to the Center of the Earth (Discover June 2007)
The deepest exploration ever: The Kola bore hole (about twice the size of a
softball) the Russians drilled in the 70s and 80s reached a depth of 7.6 miles into
the continental crust of Russia.
They hit temps of 356 degrees F.
But only reached a mere 0.2% of the way to the core.
Most scientists agree the Earth’s core is sold iron and nickel, but some disagree
Some think it could be like a nuclear reactor or even a massive crystal at the
center.
The question is will we ever reach the center to find out?
One problem is trying to recreate the conditions of the Earth’s interior (pressure &
heat) to test ways to explore its depths
One geophysicist has an interesting idea –
Open a crack in Earth’s crust with a controlled blast
Then pour in 100,000 tons of liquid iron along with several refrigerator size probes
Gravity should pull the liquid iron and probes down to the core in about one weeks time
The path behind the iron would naturally seal its self up.
The probes would communicate with the surface by seismic waves, sending up info about the cores.
Why not do it? $$$$$