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Earth’s Interior
The Science of Geology
Geologists – scientists who study the forces that make and shape the planet Earth
Rock – the material that forms Earth’s hard surface
Geologists study: the processes that create Earth’s features
search for clues about Earth’s history
study the chemical and physical properties of rock
map where different types of rock are found
describe landforms
Geology – the study of planet Earth
2 Types of Forces that Change the Earth’s Surface:
1. Constructive – forces that shape Earth’s surface by building up mountains
and landmasses
2. Destructive – forces that slowly wear away mountains and eventually every
other feature on Earth’s surface
Continents – 7 great landmasses surrounded by oceans
Seismic Waves – the indirect evidence geologists use to study Earth's interior; created
when earthquakes occur
Journey to the Center of the Earth
2 things that increase as you go towards Earth’s center:
1. Temperature
2. Pressure
Pressure – the force pushing on a surface or area
Earth’s 3 Main Layers: 1. Crust
2. Mantle
3. Core
Each layer has its own conditions and materials
The Crust
A layer of rock that forms Earth’s outer skin; Earth’s thinnest layer
Includes:
the soil and water
rocks and mountains
dry land and ocean floor
The crust is thinnest beneath the ocean
The crust is thickest beneath high mountains
basalt
2 Types of Crust:
1. Oceanic Crust – the crust beneath the ocean, consists mostly of dense
rock such as basalt
Basalt – a dark, dense rock with a fine texture
2. Continental Crust – the crust that forms the continents, consists
mostly of less dense rock such as granite
Granite – a rock that has larger crystals than basalt, is less dense and is
usually a light color
granite
The Mantle
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Below the crust
Largest layer
Solid material
Layer of hot rock
Contains 2 specially named areas
1. Lithosphere –all of the crust and the
uppermost part of the mantle together;
hard, rigid layer
• “Lithos” – in Greek means stone
2. Asthenosphere – part of the mantle
below the lithosphere; somewhat soft,
bends like plastic
• “asthenes” – in Greek means weak
The Core
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Below the mantle
Consists of 2 parts
Both parts made of Iron and
Nickel
Innermost layers
1. Outer Core – layer of molten
material (thick liquid); surrounds
the inner core
2. Inner Core – dense ball of solid
metal; extreme pressure squeezes
Iron and Nickel atoms together so
much they cannot spread into a
liquid
Earth’s Magnetic Field
• Currents in the liquid outer core spin the solid inner core
• Inner core spins slightly faster than the rest of the planet
• Spinning movement creates Earth's magnetic field
• Magnetic field effects the whole Earth
• Earth acts like a giant bar magnet
• Compass needle aligns with Earth’s magnetic field
• North seeking end of needle points to Earth’s magnetic
north pole