The Structure of

Earth

Chapter 8

System- a group of parts that work together

Energy- the ability to do work. Earth gets its this ability to work (energy) from the sun and from the center of the earth as it cools.

Earth itself is a closed system, but on earth there are open systems or spheres that influence one another.

The Spheres of the Earth System:

Atmosphere: the

relatively thin layer of gases that forms earth’s outermost layer

Mostly Oxygen & Nitrogen Dust particles Cloud droplets Earth’s weather

The Spheres of the Earth System:

Geosphere: nearly all of

earth’s mass Rocks Metal & other Minerals Has three layers

The Spheres of the Earth System:

Hydrosphere: contains all of

Earth’s water Oceans, glaciers, rivers, lakes, ground

water, & water vapor Covers ¾ of the Earth Mostly salt. Only a tiny portion is drinkable.

The Spheres of the Earth System:

Biosphere: the part of Earth where life exists.

Feedback = the communication between the spheres

Inside Earth

GEOLOGY is the study of what’s on and in the Earth.

GEOLOGISTS are scientists who study the processes that create Earth’s features and search for clues about Earth’s HISTORY.

What does a geologist do???

They study the CHEMICAL and PHYSICAL characteristics of rock, the material that forms Earth’s hard surface.

They map where different types of rocks are found and describe LANDFORMS, the features sculptured in rock and soil by water, wind, and waves.

They study how seismic waves (waves caused by earthquakes) travel through earth.

2 VERY IMPORTANT FORCES!

Two forces Change Earth’s Surface: CONSTRUCTIVE forces – shape the

surface by building up mountains and landmasses.

Destructive forces are those that slowly wear away Land masses and, eventually, every other feature on the surface.

A Peek Inside…

Three main layers:CRUSTMANTLECORE

The Layers of the Earth

Notice where the CRUST is.

THE CRUST

The layer of rock that forms Earth’s OUTER skin.

Includes dry land and the OCEAN floor.

Approx. 5 - 40 km thick.

More about the CRUST

COMPOSITION – oxygen, silicon, aluminum, calcium, iron, sodium, potassium, magnesium

Temperature VARIES

There are 2 types of CRUST

Oceanic crust - the crust beneath the OCEAN The THINNEST crust is under the

ocean.CONTINENTAL crust – the crust that

forms the continents and some major islands.

A Special Note:

The deeper down into Earth, the greater the pressure and temperature.

(just below earth the rock is cool, but after about 20meters down the temperature

increases nearly 1oC/40m)

THE MANTLE The layer of HOT ROCK below the

crust Starts 5 – 40 km beneath the

surface Approx. 3,000 km thick COMPOSITION – silicon, oxygen,

iron, magnesium Temperature – 870 °C

THREE mantle layers

Lithosphere – brittle rock Asthenosphere – less rigid rock (metal spoon) Mesosphere – hot but more rigid due to pressure

THE CORE

Makes up 1/3 of Earth’s MASS, but only 15% of its volume. Composition – IRON and

NICKEL

Outer core – layer of MOLTEN METAL that surrounds the inner core The liquid metal causes CURRENTS* Temperature – 2,200 °C

Approx. 2,250 km thick

Inner core – dense ball of solid metal under extreme pressure.

The solid inner core spins at a slightly FASTER rate than the spinning of the whole Earth.

Earth’s MAGNETIC field is created by this movement

Causes the planet to act like a giant bar MAGNET

Temperature – 5,000 °C Approx. 1,200 km thick

BACK TO THOSE CURRENTS. . .

prezi

Heat Transfer (from warm to cool):Conduction-by touchingConvection – by the movement of fluidRadiation- by light

Density = mass/volume

So. . .

Heat from the core (and the mantle itself) act like a stove top heating soup. . . this causes convection currents (hot to cold- rising & sinking)