Layers of the Earth

Structure of the EarthStructure of the Earth: series of spheres held together by gravity

* center of Earth is most dense; it gets less dense as you move outward from the center

Structure of Earth ctd

* center of Earth is most dense; it gets less dense as you move outward from the center

See pg. 10 of ESRTs

Structure of the Earth CtdSee pg. 10 of ESRTs

Crust: thin, outermost solid layer of the Earth (2 kinds)

See pg. 10 of ESRTs

Mantle: thick, mainly solid layer (~ 2800 km thick)

Core: innermost region of the Earth (2 parts)

a) oceanic: 20–40 km thick; basalt; 3 g/cm3 (MORE dense)

b) continental: 40–65 km thick; granite; 2.7 g/cm3 (LESS dense)

a) outer core: LIQUID iron (~ 2200 km thick)

b) inner core: solid iron & nickel (~ 1300 km thick)

Outer core is LIQUID – WRITE this in your ESRTs NOW!!

Structure of the Earth continuedLithosphere: the crust & upper part of the mantle (~100 km thick)

* * dense outer shell of Earth composed of rockSolid rock

Info on the above comes from:a) seismic data (we hit the Earth with waves)b) meteoritesc) drill holesd) volcanoes

* * oxygen & silicon are the 2 most abundant elements

Asthenosphere: lower part of the mantle (~ 500 km thick)

* * NOT brittle like rock; it’s squishyductile(plastic putty)

Surface Layer (liquid)Hydrosphere: consists of the Earth’s water (H2O)

(oceans, lakes, rivers, etc)water

* * oceans cover 70% of Earth’s surface (on average ~ 3.8 km deep / thick

Pg 1 ESRTS

Hydrosphere: consists of the Earth’s water (H2O)

Exterior Layer (gases)Atmosphere: shell of gases surrounding Earth

Extends many km up to the edge of space

It’s layered into temperature zones

Each layer is separated from the next by a “pause” (interface)

Pg 14 ESRTs

Pg 14 ESRTs

Exterior Layer (gases)The Atmosphere’s composition is mainly:78% nitrogen21% oxygen1% other (argon, carbon dioxide, helium, water vapor)

Pg 1 ESRTS

DRAW the layers of the atmosphere

troposphere

stratosphere

mesosphere

thermosphere

troposphere

stratosphere

mesosphere

thermospheremesopause

stratopause

tropopause

least dense

most dense

dens

ity d

ecre

ases

Earth

fades out to space

Pg. 14 ESRTs

only layer w/ water vapor

Layers of the Earth - RECAP

** see pg 10 of ESRTs – Inferred Properties of Earth’s Interior…

** see pg 1 of ESRTs – Average Chemical Composition of Earth’s Crust, Hydrosphere and Troposphere

** see pg 14 of ESRTs – Selected Properties of Earth’s Atmosphere