AIM: How have geologists learned about Earth’s interior? What are the characteristics of Earth’s...

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AIM: How have geologists learned about Earth’s interior? What are the characteristics of Earth’s crust, mantle and core?

OBJ: Given notes and activity sheet SWBAT describe techniques used to investigate Earth’s interior and the characteristics of Earth’s crust, mantle and core with 70% accuracy.b

DN: Hand-in Ecology and Solutions Activity Sheets; Distribute Inside Earth Textbooks

ACT: Text, read p. 6-13, Complete Earth’s Interior Activity Sheet; Review ResultsWork on Being A Scientist PacketWork on eSpark Assignment (iPads)

HW: Text, read p. 14-17; Work on Being A Scientist Packet; Interim Exam, Thursday, January 22.

How have geologists learned about Earth’s Interior?

Rock Samples: drilling up to 12 km into Earth; tectonic faulting & uplift has revealed rocks from more than 100 km depth.

Seismic Waves: because rock layers have different densities, seismic waves move at different speeds through the rock layers. Geophysicists use this seismic wave data to construct a “picture” of the earth’s deep internal layers (e.g., crust, mantle, core)

Seismogram

Crust (outermost Earth layer)Crust: solid layer of rock. Two types:

•continental crust: forms the continent, granite in composition

•oceanic crust: forms the ocean floor, basalt in composition

Mantle (thick middle layer)Mantle: hot rock nearly 3000 km thick

Lithosphere: rigid, solid rock consisting of the crust and hot uppermost mantle; 100 km thick

Asthenosphere: softer, hot, clay-like rock that can bend.

Lower Mantle: solid rock

CoreCore: metal iron & nickel composition; liquid outer core and solid inner core; 3,486 km thick.

Outer core: the movement of the liquid outer core generates the Earth’s magnetic field.

Inner core: is solid because extreme pressure prevents the Fe, Ni atoms from spreading apart and becoming a liquid.

Earth’s magnetic field created by movement of the outer liquid iron core

Moving liquid metal created magnetic field in laboratory

Earth’s magnetic field protects life from harmful solar winds

Sun (star)Earth

Earth’s magnetic field

Solar winds