Earth’s Layers SC Standard 8-3.1 Summarize the 3layers of Earth on the basis of relative position , density and composition.
Earth is divided into 3 basic layers:1. Crust2. Mantle3. Core These layers are then subdivided into smaller layers.
CRUST :•Is the outermost layer on the earth.(EGG SHELL)•Thickness varies. Under mountainsit can be as thick as 60 km and lessthan 5 km under the ocean.•It is the least dense of all the layers.(lightest layer)•It is made up of silicon and oxygen.
2 TYPES OF CRUST :• Oceanic crust isvery dense, madeof Basalt.• Continental crustis less dense,made of Granite.
MANTLE :• Located below the crust. (EggWhite)• It is the largest layer (about 2900km thick). Rock layers aremovable. (plastic)• Hot soften rocks made up of moremagnesium and iron.• Density increases with depth dueto increase in pressure.
MANTLE : Divided into 2 parts• Upper mantle• Lower mantle.• Contains the “Moho” (Mohorovicicdiscontinunity)
CORE : (Egg Yolk)• Located below the Mantle.• It is divided into 2 layers Outer Core Inner Core
Outer Core :• is liquid and is made up of mostlyiron (easily magnetized)• The movement of materials in theliquid O.C. is inferred to be thecause of Earth’s magnetic field!(highlight in your notes)• The O.C. is about 2250 km thick.
Inner Core :• Is the center of the Earth – 1200km thick.• It’s solid iron and nickel. Mostdense layer (heaviest) (highlight innotes)• The increased pressurecauses the I.C. to be solid
In your notes lets draw together a diagram of the Earth. CRUSTMANTLE OUTER CORE INNER CORE
Look at the sub-layers of the mantleLITHOSPHERE:• This is the “crunchy” layer of the Earth.• It includes the crust and the veryuppermost part of the upper MantleASTHENOSPHERE:• Soft – can bend like plastic, layer in theupper portion of the mantle• It is located right below the Lithosphere. Lithosphere floats on this layer (like jello)
In Review:1.What are the 3 main layers of the Earth?Crust, Mantle, Core2.Which layer is the least dense?Crust3.Which core layer is solid iron and nickel?Inner core4.What is the name given to the “crunchy” layer of the crust and uppermost part of the mantle?Lithosphere5. The motion in this layer is the reason Earth has a magnetic field.Outer core
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