Transcript Inside the Earth

Bellringer
• On Friday you wrote about taking a
journey to the center of the earth. Do you
think it would really be possible to journey
to the center of the earth? Why or Why
Not?
• What were the 3 main layers of the earth
by composition?
• What are the 5 physical layers of the
earth?
Inside the Earth
Density and Earth’s materials
•
Scientists conclude that Earth formed from the
gas and dust that surrounded our young sun.
•
At first, Earth’s surface was made of the same
materials as its center.
•
Later, the materials melted and became fluid.
•
More dense materials settle toward the center.
•
Less dense materials rose toward the surface.
•
This created the “layers” of the earth.
Layers by Composition
(What it is made of)
• Crust
• Mantle
• Core
The Crust
•
•
•
•
Thin, outer layer.
less than 1% of Earth’s mass
5-70km thick
Part of the lithosphere.
• Continental Crust
-
thick (10-70km)
- buoyant (less dense than
oceanic crust- it “floats”)
- mostly old
• Oceanic Crust
• - thin (~7 km)
- dense (sinks under
continental crust)
- young
The Mantle
• Layer beneath the
crust
• 64% of mass of
Earth
• 2,900 km thick
• Made of
– lithosphere
– asthenosphere
– mesosphere
Convection Currents
COOL
HOT
-The middle mantle
"flows" because of
convection currents.
- Convection currents
are caused by the very
hot material at the
deepest part of the
mantle rising, then
cooling and sinking
again --repeating this
cycle over and over.
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
Physical Structure of the Earth (5 Layers)
-Lithosphere
Mesosphere
-Asthenosphere
-Mesosphere
-Outer Core
-Inner Core
© Copyright 2006. M. J. Krech. All rights reserved.
The Lithosphere
The crust and the upper layer of the
mantle together make up a zone of rigid,
brittle rock called the Lithosphere. Earth’s
lithosphere is broken into about 19 pieces
called 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
The Outer Core
- The outer core is
so hot that the
metals in it are all
in the liquid state.
- The outer core is
composed of the
melted metals of
nickel and iron.
The Inner Core
- The inner core of
the Earth is a solid
layer of iron and
nickel.
- It has temperatures
and pressures so
great that the metals
are squeezed
together too tight to
move like a liquid,
but are forced to
vibrate in place like
a solid.
Throw Your Hands Up For the
Layers of the Earth!
Chorus
Throw your hands up for the layers of the earth •
Throw ‘em up for what’s below the surface
Throw your hands up, and let’s discuss
•
The inner core, outer core, mantle, and crust
Verse I
The layer we’ll discuss first
Is the central inner core, in the center of the earth
A solid ball buried below the dirt
We believe it’s primarily metallic iron
You could never take a trip to the inner core, right?
The heat will burn you up, 9,000º Fahrenheit
4,000 miles below the Earth’s crust
One down three to go y’all.
1,800 miles from the tip top
The outer core is hard at work and it don’t stop.
It’s busy spinning around the inner core, and listen,
This steady movement causes Earth’s magnetism.
Ranging from 4 to 9,000 degrees,
It contributes 1/5 of the heat flowin’ to you and me.
•
It’s liquid metals that violently flow
So let it settle… and when you’re ready let me know.
Just…
Chorus
Verse II
The mantle layer is the largest of the class.
About half of our planet’s mass.
The mantle is composed of very hot dense rocks,
That move and flow, always on the go, they never lock,
Never stop, and they’re responsible for tectonic shift
Please believe the Earth’s plates are adrift
It’s pretty thick and the heat is awesome
1,600 at the top, 4,000 at the bottom
The continental crust’s surface is where we breathe
A lot of rock up to 25 miles deep.
The oceanic crust is next door
It’s 3-5 miles thick below the ocean floor.
Earth’s surface: 70% H20.
Where do you get all that water? Salty sea flow,
fresh water’s in the glaciers, ice caps, and snow.
Chorus