The document describes the structure and composition of Earth. It discusses how Earth is made up of four interconnected spheres - the atmosphere, geosphere, hydrosphere, and biosphere. It then focuses on the layers that make up Earth's interior, including the crust, mantle, and core. The crust and mantle are composed mainly of oxygen, silicon, and metals. Heat from the core drives convection currents in the mantle and outer core.

1. The Structure of
Earth
Chapter 8

2. 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.

3. 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

4. The Spheres of the
Earth System:
Geosphere: nearly all of
earth’s mass
 Rocks
 Metal & other Minerals
 Has three layers

5. 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.

6. The Spheres of the
Earth System:
Biosphere: the part of
Earth where life exists.
Feedback = the communication between
the spheres

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

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

10. 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.

12. 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.

13. A Peek Inside…
Three main layers:
CRUST
MANTLE
CORE

14. The Layers of the Earth

15. Notice where the CRUST is.

16. THE CRUST
The layer of rock that forms
Earth’s OUTER skin.
Includes dry land and the
OCEAN floor.
Approx. 5 - 40 km thick.

17. More about the CRUST
COMPOSITION – oxygen,
silicon, aluminum, calcium,
iron, sodium, potassium,
magnesium
Temperature VARIES

18. 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.

19. 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)

20. 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

21. THREE mantle layers
 Lithosphere – brittle rock
 Asthenosphere – less rigid rock (metal spoon)
 Mesosphere – hot but more rigid due to pressure

22. THE CORE
Makes up 1/3 of Earth’s MASS,
but only 15% of its volume.
 Composition – IRON and
NICKEL

23. 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

24. 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

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

26. BACK TO THOSE CURRENTS. . .
prezi
Heat Transfer (from warm to cool):
 Conduction-by touching
 Convection – by the movement of fluid
 Radiation- by light

27. 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)