unit 3 dynamic earth
DESCRIPTION
Unit 3 Dynamic Earth. The Earth is divided into 4 layers. 1. Crust (Lithosphere) 2. Mantle (Magma) 3. Outer Core 4. Inner Core. Layers of the Earth (List the 4 layers of the earth, choose a color for each layer and color diagram the appropriate color). Why does the Earth have layers?. - PowerPoint PPT PresentationTRANSCRIPT
Unit 3Dynamic Earth
The Earth is divided into 4 layers
1. Crust (Lithosphere) 2. Mantle (Magma) 3. Outer Core 4. Inner Core
Layers of the Earth (List the 4 layers of the earth, choose a color for each layer
and color diagram the appropriate color)
Why does the Earth have layers?
The layers formed because of their different densities.
The less dense material is found in the crust.
The more dense compounds sank to the center of Earth.
Crust
Outermost layer Thinnest layer (5-100 km thick) Two types: Continental and Oceanic Click here to see the 2 types of crust
Oceanic and Continental Crust
Mantle
Just beneath crust Contains most of Earth’s mass (67%) Thickest layer (2900 km thick) Hot, gooey layer made of magma (liquid
rock – molten rock)
Outer Core
Hot liquid Iron 2,200 km thick
Inner Core
Solid Iron/Nickel (metal) 1250 km thick
Earth’s Layers The crust is also known as the lithosphere. The broken sections of the crust are
referred to as plates (tectonic). These plates fit together along Earth’s
surface like a puzzle. The plates move along the surface very
slowly. The upper part of the mantle acts like a
plastic and is called the asthenosphere. It allows the plates to move.
Layer Description Composition (make-up)
Physical Properties
Crust (Lithosphere)
Thinnest layer (5-100 km thick)
Made of rock • Rock• Solid• Thinnest
layerMantle Thickest Layer
just beneath the crust(2,900 km thick)
Made of molten (liquid) rock – MAGMAMore dense than the crust
• Hot molten rock
• 2/3 of Earth’s Mass
• MOVEOuter Core Liquid layer of
the core(2,200 km thick)
Hot liquid iron • Liquid
Inner Core Solid layer of the core (METAL)(6,380 km below surface)
Solid iron and nickel
• Solid
Tectonic Plates
• Plate tectonics is the theory that the lithosphere is divided up into plates that move along the asthenosphere. (upper part of the mantle)
Three types of Plate Boundaries• 1. Convergent – where two plates are
colliding• 2. Divergent – where two plates are
separating• 3. Transform – where two plates slide
against each other
Convergent Boundaries
Divergent Boundary
Transform Boundary
Wegener’s Hypothesis of Continental Drift
• Continental Drift – is the hypothesis that the continents once formed a single continent called Pangaea. This continent broke up and the pieces have moved to their present locations.
Evidence that helps support Continental Drift
Similar findings on opposite sides of the Atlantic include:• Fossils• Plants• Mountain Ranges• Matching Rock Types
Movement of Tectonic Plates• What causes the tectonic plates to
move?Convection Currents
• Convection – the movement of thermal energy through a fluid.
Hottest magma rises Cooler magma sinks
Forces that move Tectonic PlatesType of Force
Force Description
Ridge Push Lava coming out of the mantle ‘pushes’ the plates apartView Ridge Push
Convection Hot liquid rock rises and cooler liquid rock sinks causing the crust to go away from the ridge.
Slab pull Oceanic Crust slides downward because of the force of GravityView Slab Pull
Deformation of the Earth’s Crust
• Deformation – Shape of rock changes (folds).
• Compression – Stress that occurs when forces act to squeeze an object.
• Tension – Stress that occurs when forces act to stretch an object.
Types of stress that deform rock:
• Folding – the bending of rock layers
• Faulting – the surface along which rocks break and slide past each other.
• Fault Line
EARTHQUAKES• An earthquake is the shaking of the Earth’s
crust.
• The study of earthquakes is called Seismology
• The instrument used to measure an earthquakes magnitude (strength) is a seismometer and seismograph
Seismometers and Seismographs
EARTHQUAKE DAMAGE
EARTHQUAKES
• Earthquakes occur along PLATE BOUNDARIES (edges of the crustal plates)
• The most active earthquake zone is along the pacific ocean, also known as THE RING OF FIRE.
EARTHQUAKES
Three Types of Plate Boundaries
• Convergent
Mountains
This motion creates:
• Divergent • Transform
VolcanoesSeafloor spreadingRidges
Earthquakes
Seismic Waves• When an earthquake occurs it produces
vibrations, also known as seismic waves.
• Seismic waves are the reason we know the interior of the Earth.
Seismic Waves
• Speed: FAST Speed: SLOW
Shadow Zones• The solid core of the Earth blocks and bends
the vibrations from an earthquake from reaching the other side of the Earth.
• P-waves can travel through the interior of the earth
• S-waves can not pass through the liquid portions of the earth.
Measuring Earthquakes• Richter Scale – measures the magnitude
(strength) of the earthquake from 1 to 10.
• Mercalli Scale – measures the amount of damage done from an earthquake from I-XII.
Earthquake SafetyBefore the shaking:
• 1. Prepare emergency kit– Water– First Aid Kit– Radio / Batteries– Canned food / Can opener
• 2. Prepare escape route
• 3. Home Safety Plan– Remove objects from high shelves
Earthquake SafetyDuring the shaking:
1. Get under a table
2. Get in a doorway
3. Stay away from objects that may fall on you
Earthquake SafetyAfter the shaking:
1. Get away from danger
2. Go to your previously appointed emergency location
3. Do not go back indoors until advised