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Geography Chapter 2
A Living Planet
The Earth Inside and Out pp.27 – 47
Bodies of Water and Land Forms pp. 32-36
Internal Forces Shaping the Earth pp.37-41
External Forces Shaping the Earth pp. 42-45
1. Earth the Inside and Out
• Earth is part of the Solar System
• Third rock from the Sun
• Solar system is a group of bodies that orbit the
Sun
The Solar System
2. The Structure of the Earth
About 24000 mile Circumference and 7900 mile
diameter
Made up of Three main parts
Core – center made up of Iron and Nickel
Mantle – Soft layers of molten rock called Magma
Crust – Solid rocky outer layer we live on
Parts of the Core
Inner Core – made of highly pressurized
Iron and Nickel 760 mile radius
Outer Core – Surrounds the Inner Core
1380 miles thick
Mantle
Lower Mantle – Surrounds the outer core 1300
miles thick
Upper Mantle – Made of the Asthenosphere and
Lithosphere (inner layers of Crust ) 500 Miles thick
Mantle composed of hot liquid magma
Crust
Top of Lithosphere
Outer layer where we live. Thin layer of rock on
the outer surface of the Earth
On and Above the Earth
Atmosphere – gases that surround the Earth
allow us to breath
Lithosphere - Rocky part of the Earth we live on,
the continents
Hydrosphere – Oceans / water
Biosphere – where we live
Continental Drift
The theory that all the continents once formed one supercontinent and
drifted apart on Magma. Called Pangaea
Disaster !
Asteroid Hits Earth contributing the extinction of Dinosaurs and the
eventual rise of mammals.
2. Bodies of Water and Landforms
Oceans, Seas
Lakes Rivers Streams
Ground Water
Oceans, And Seas
Largest bodies of Water
71% of the Earth surface
Four Oceans Atlantic, Pacific, Indian, Artic
The Four Oceans
Ocean Motion
Oceans are made of salt water
The flow through 3 basic motions
Tides – Rise and fall with the Lunar Cycle
Currents – Act like rivers flowing through the
ocean
Waves – Swell or ridges produced by winds
Tides – Rise and fall with the Moon
The Moons gravitational pull on the Earth cause the waters to Swell towards
the Moon
High Tide and Low Tide
Ocean Currents
Waves
Waves: Storm Surge
Example of Storm Surge
Waves: Tsunami
Caused By an under water disturbance
Can travel thousands of miles
Extremely destructive
Hydrologic Cycle: The interaction between the
Earth’s waters and atmosphere
Lakes Rivers and Streams
95 % of the Earth’s fresh water supply is in lakes
Lake Baikal – Largest in the world
Great Lakes – Result of Glaciers from the Ice Age
Rivers and Stream move water through channels to large bodies
Connect to each other forming Drainage Basins
Ground Water
Landforms
Naturally formed features on the Earths surface
Oceanic Landforms:
Continental Shelf
3. Internal forces shaping the Earth
Continental Landforms
Relief - Feature that separates one landform from
another
Topography – Combination of surface shape and the
composition of a land form
Plate Tectonics
Internal forces shape the Earths surface
Heated magma moves up to the crust and cools and then
circulates downward this movement causes the crust to
shift
Enormous moving pieces of crust called Tectonic Plates
ride on the Magma and shift from time to time
Plate Movement
Tectonic Plates move in four ways
1. Spreading or moving apart
2. Subduction or diving under each other
3. Collision or crashing into each other
4. Sliding or shearing past each other
Three types of boundaries mark plate movement
1. Divergent – spreading apart
2. Convergent – colliding causing one plate to rise and
other to fall
3. Transform – Plates sliding past each other
Divergent Boundary
Hot magma rises and pushes the plates apart
Convergent Subduction
When an oceanic plate collides with a continental plate it creates a
volcanic zone
Convergent Collision
When two continental plates collide it creates a mountain range
Transformation
Plates slide past each other causing a fault line
Folds and Faults
When two plates meet they cause folding and cracking.
The rock bends under pressure exerted by the plates
When the plates crack it create a fault line
Earthquakes
Plates grinding and slipping past each other causing the Earth to shake
Thousands occur each year but most are so small you can not feel them
Epicenter - the point where the earthquake begins
Seismograph – detects earthquakes
Richter scale – measures the power of an earthquake on a scale of 1-10
Famous Earthquakes
1906 San Francisco
1989 Loma Preiti
Famous Earthquakes
1906 San Francisco
1989 Loma Preita
Volcanoes –
Eruptions of Magma to the Earths surface
Pacific Ring of Fire
The Fault lines and volcanoes that ring the west coast for North and
South American and over to Asia and Australia
4. External Forces Shaping the Earth
Weathering
Loess
Delta
Glacier
Sediment
Glaciation
Mechanical Weathering
Moraine
Chemical Weathering
Humus
Erosion
Weathering
Refers to physical and chemical process that change the
characteristic of rock on or near the Earths surface
Occurs Slowly over many years or
centuries
Weathering causes large pieces of rock to
break down to smaller and smaller pieces
These are called Sediment
Sediment is small pieces of weathered
rock mostly mud sand or silt
Two types of weathering
1. Mechanical
2. Chemical
Mechanical Weathering
Does not change the composition of the
rock only the size
All sorts of things can cause mechanical
Weathering
Water / Ice / Frost
Plants
Human activities
When it breaks down small enough the
sediment combines with organic material
to become soil
Chemical Weathering
When rock is changed into a new
substance altering the composition of the
rock.
Some minerals reacts with chemicals and
change
Iron reacts with water and rust
I
Erosion
Occurs when a weathered material is
moved by the wind or water
It is done either by flowing water,
Wind, or glaciers
Water Erosion
Water Erosion – as water speeds up it
carries the sediment from the river basin
As it slows it deposits it in another
location reshaping the river banks
The mouth of a river forms a delta from all
the deposits of sediment
Wind Erosion
Similar to Water Erosion
Transports sediment changing the
landscape
Dust storms
The wind deposits the loess or
sediment that is carried in a dust
storm
Glacial Erosion
Glacier large long sheet of Ice that moves
because of gravity
Pushes or carried sediment
Can carve out landscapes over time
Moraine is the rocks left behind a glacier
Building Soil
Humus is the combination of organic
material and sediment
Organic matter helps support plant
growth
1. Parent Material - the chemical
composition of the rock and
organic material
2. Relief – Steep slopes like
mountains erode easily
3. Organism – plants and small
animals that deposit material
Five Factors contribute to creating
soil
4. Climate – how hot, cold wet or dry
an area is
5. Time – about 2.5 cubic
centimeters a century