Download Chapter One: Plate Tectonics

Chapter One: Plate
Tectonics
Section One: Earth’s Interior
Pages 16-24
Title Page
• Look over Chapter
One: Plate Tectonics
(pages 14-47) to help
you create a title page
in your ISN #43.
• Words Worth Knowing
will be on ISN #44
Geologists…
• are scientists who study the forces that
make and shape planet Earth.
• study the chemical and physical
characteristics of rock.
• map where different types of rocks are
found on and beneath the surface.
• describe landforms, features that form in
rock by water, wind, and waves.
Forces
Two groups of forces that change the
surface of the Earth:
1. Constructive forces = shape the
surface by building up mountains and
landmasses, ex. a new island
2. Destructive forces = slowly wear away
mountains and landmasses, ex. ocean
waves wear away a shoreline
What is inside the Earth?
• Geologists cannot observe Earth’s interior
directly so they rely on observations.
• When earthquakes occur, they produce
seismic waves. Geologists record the
seismic waves and study how they travel
through Earth.
• The data tells us that the Earth is made up
of many layers.
Seismic Waves
• QUEST Explainer: Seismic Waves
http://vimeo.com/74338930
Journey to the Center of Earth
If you could travel to the center of Earth…
• What would happen to the temperature
as you traveled?
– the temperature would rise as you descend
• What happens with pressure?
– the deeper you go, the greater the
pressure; this is because of the weight of
the rock
Layers of Earth
Three main layers make up Earth’s interior:
the crust, the mantle, and the core.
Each layer has its own conditions and
materials.
The Crust
• The crust is the thin layer of
rock that forms Earth’s outer surface;
includes both dry land and ocean floor.
• Oceanic crust = thin crust beneath the
ocean; consists mostly of DENSE rocks
like basalt
• Continental crust = thick crust that
forms the continents; consists mainly of
LESS DENSE rocks like granite
The Mantle
• The mantle is the hot, solid
material between Earth’s crust
and core.
• The mantle is very thick, nearly
3,000 km thick; it goes almost
halfway to the center of Earth.
• There are 2 fancy layers in the
mantle, the lithosphere and
asthenosphere.
Lithosphere
• Lithosphere = a rigid
layer consisting of the
crust and uppermost
part of the mantle
• lithos means “stone”
• It averages about 100
km thick.
Asthenosphere
• Asthenosphere = the soft layer of the mantle
on which the lithosphere floats
• asthenes means “weak”
• It is soft, material in this layer flows slowly.
• The lithosphere floats on top of the
asthenosphere.
The Core
• Scientists estimate that temperatures
within Earth’s outer core and inner core,
range from 2,000 to 5,000 *C.
• Both made of iron (Fe) and nickel (Ni).
• Outer core is liquid while the inner core is
solid (so much pressure, Fe and Ni atoms
can not spread out)
Earth’s Magnetic Field
• Currents in the liquid outer core force the
solid inner core to spin at a slightly faster
rate than the spinning of the whole Earth.
• This movement creates Earth’s magnetic
field, which causes the planet to act like a
giant bar magnet.
Compass
How does a compass work?
• The compass needle aligns with the lines
of force in Earth’s magnetic field.
• The north seeking end of the compass
needle points to Earth’s magnetic north
pole.
• How a Compass Works
https://www.youtube.com/watch?v=lSaXhVEE4oQ
Words Worth Knowing (ISN #44)
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Geologist
Constructive forces
Destructive forces
Seismic wave
Basalt
Granite
Lithosphere
Asthenosphere