The document summarizes the three main layers of Earth - crust, mantle, and core. The crust is the outermost layer and varies in thickness and composition between oceanic and continental crust. Below the crust is the mantle, the largest layer made of hotter rocks that increase in density with depth. The innermost layer is the core, divided into a liquid outer core that generates Earth's magnetic field and a solid inner core made of iron and nickel.

1. Earth’s Layers
SC Standard 8-3.1 Summarize the 3
layers of Earth on the basis of relative
position , density and composition.

2. Earth is divided intoEarth is divided into 3 basic3 basic
layerslayers::
1. Crust1. Crust
2. Mantle2. Mantle
3. Core3. Core
These layers are thenThese layers are then
subdivided into smaller layers.subdivided into smaller layers.

3. CRUSTCRUST::
•Is theIs the outermost layeroutermost layer on the earth.on the earth.
(EGG SHELL)(EGG SHELL)
•Thickness variesThickness varies. Under mountains. Under mountains
it can be as thick as 60 km and lessit can be as thick as 60 km and less
than 5 km under the ocean.than 5 km under the ocean.
•It is theIt is the least denseleast dense of all the layers.of all the layers.
(lightest layer)(lightest layer)
•It is made up ofIt is made up of siliconsilicon andand oxygenoxygen..

4. • Oceanic crustOceanic crust isis
very dense, madevery dense, made
ofof Basalt.Basalt.
• Continental crustContinental crust
is less dense,is less dense,
made ofmade of Granite.Granite.
2 TYPES OF CRUST2 TYPES OF CRUST ::

5. BASALT
GRANITE

6. MANTLEMANTLE::
• LocatedLocated belowbelow the crust.the crust. (Egg(Egg
White)White)
• It is theIt is the largest layerlargest layer (about 2900(about 2900
km thick). Rock layers arekm thick). Rock layers are
movable. (plastic)movable. (plastic)
• Hot soften rocks made up of moreHot soften rocks made up of more
magnesiummagnesium andand ironiron..
• Density increasesDensity increases with depth duewith depth due
to increase in pressure.to increase in pressure.

7. MANTLEMANTLE:: Divided into 2 partsDivided into 2 parts
• Upper mantleUpper mantle
• Lower mantleLower mantle..
• Contains the “Moho”Contains the “Moho” (Mohorovicic(Mohorovicic
discontinunity)discontinunity)

8. CORECORE:: (Egg Yolk)(Egg Yolk)
• Located below the Mantle.Located below the Mantle.
• It is divided into 2 layersIt is divided into 2 layers
Outer CoreOuter Core
Inner CoreInner Core

9. Outer CoreOuter Core ::
• isis liquidliquid and is made up of mostlyand is made up of mostly
ironiron (easily magnetized)(easily magnetized)
• The movement of materials in theThe movement of materials in the
liquid O.C. isliquid O.C. is inferredinferred to be theto be the
cause of Earth’scause of Earth’s magnetic fieldmagnetic field!!
(highlight in your notes)(highlight in your notes)
• The O.C. is about 2250 km thick.The O.C. is about 2250 km thick.

10. Inner CoreInner Core ::
• Is theIs the centercenter of the Earth – 1200of the Earth – 1200
km thick.km thick.
• It’sIt’s solidsolid iron and nickel. Mostiron and nickel. Most
dense layer (heaviest)dense layer (heaviest) (highlight in(highlight in
notes)notes)
• The increased pressureThe increased pressure
causes the I.C. to be solidcauses the I.C. to be solid

11. In your notes lets draw together a diagram of the Earth.
CRUST
MANTLE
OUTER CORE
INNER CORE

13. Look at the sub-layers of the mantle
LITHOSPHERELITHOSPHERE::
• This is the “crunchy” layer of the Earth.This is the “crunchy” layer of the Earth.
• It includes theIt includes the crustcrust and the veryand the very
uppermost part of the upper Mantleuppermost part of the upper Mantle
ASTHENOSPHEREASTHENOSPHERE::
• Soft – can bend like plastic, layer in theSoft – can bend like plastic, layer in the
upper portion of the mantleupper portion of the mantle
• It is located right below the Lithosphere.It is located right below the Lithosphere.
Lithosphere floats on this layer (like jello)Lithosphere floats on this layer (like jello)

14. CRUST
MANTLE
OUTER CORE
INNER CORE
Lithosphere
Asthenosphere

15. In Review:
1.What are the 3 main layers of the Earth?
Crust, Mantle, Core
2.Which layer is the least dense?
Crust
3.Which core layer is solid iron and nickel?
Inner core
4.What is the name given to the “crunchy” layer of
the crust and uppermost part of the mantle?
Lithosphere
5. The motion in this layer is the reason Earth has
a magnetic field.
Outer core