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4.1 E

ARTH

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S

DAHS Mr. Sweet

F

ORMATION

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BJECTIVES

    Explain how most scientists explain the formation of our solar system.

Describe Earth’s size and shape and the arrangement of its layers.

List three sources of Earth’s internal heat.

Describe Earth’s magnetic field.

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N

EBULAR

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YPOTHESIS

      Most widely accepted model for solar system formation 4.6 billion years ago Cloud of gas and dust rotating in space Shrank due to pull of gravity, spinning faster Material collected at center and became hot.

Hydrogen fusion began creating our sun.

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LANETISMALS

  Frictional, electromagnetic, and gravitational forces formed solid particles of ice and rock.

Eventually formed planets and moons.

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BLATE

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PHEROID

   A sphere that bulges in the center.

Shape of Earth.

Proof  Measuring the weight of object at several places on Earth.

 195 Newtons at Poles and 194 Newtons at equator.

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E

ARTH

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EASUREMENTS

 Total surface area   510 million square km 55 continental USA’s    149 million square km is above sea level Ocean covers 361 million square km 29% dry, 71% wet

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O

RIGINAL

E

ARTH

 Looked like the moon     Same material all the way thru Collisions created heat Heat melted iron and nickel Denser material moved to the center and lighter materials to the surface

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L

AYERS

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F

E

ARTH

 Inner Core   Outer Core Mantle   Lithosphere Asthenosphere  Crust

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I

NNER

C

ORE

 Solid iron and nickel

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O

UTER

C

ORE

  Surrounds the inner core Composed of liquid iron and nickel

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ANTLE

   Thickest of Earth’s layers Iron, Silicon, and magnesium Solid  High pressure and temperatures cause it to behave as a liquid.

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C

RUST

 Thin, rigid layer  Lighter rocks

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O

THERS

 Lithosphere   Crust and uppermost mantle More rigid material  Asthenosphere    Slushlike layer of mantle Lithosphere floats on top Cause of plate tectonics

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E

ARTH

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H

EAT

 Meteorite impacts    Compression of Earth’s interior Decay of radioactive isotopes Slowly losing heat  Differences in rock, crust thickness, and radioactive rock

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EMPERATURE

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T

D

EPTH

  Above 70 feet temperature remains constant year round Below 70 feet temperature rises 1 o Celcius every 40 meters

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M

AGNETIC

F

IELD

    North Pole is the positive pole South Pole is the negative pole Tilted 11 O the poles away from Hypothesized that the fluid outer core creates the magnetic field  Iron moves through and electric field creating another electric field

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S

ECTION

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EVIEW

4.1

 Page 74 Numbers 1, 2, 3, and 4

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