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Plate Tectonics
Exploring Inside the Earth
Geologists have used evidence from rock
samples and evidence from seismic waves to
learn about Earth’s interior.
Geologists
are scientists
who study
the forces
that make
and shape
planet Earth.
Geology
is the
study of
planet
Earth.
Studying Surface Changes
Constructive forces
shape the surface by
building up mountains.
Destructive forces are
those that slowly wear
away mountains and,
eventually, every other
feature on the surface.
The Crust
The crust is a layer
of solid rock that
includes both dry
land and the ocean
floor.
Three main layers make up
Earth’s interior: the crust,
the mantle, and the core.
Each layer has its own
conditions and materials.
The Mantle
Earth’s mantle is made up of rock that is very hot,
but solid. The mantle is divided into layers
based on the physical characteristics of those
layers.
The Core
The core is made mostly of the metals iron and
nickel. It consists of two parts–a liquid outer
core and a solid inner core.
The Plates and How They Move
The lithosphere is broken into separate sections called plates.
The theory of plate tectonics explains the formation, movement,
and subduction of Earth’s plates.
Review: Heat Transfer
There are three types of heat transfer:
radiation, conduction, and convection.
Heat transfer – the
movement of
energy from a
warmer object to a
cooler object
Radiation – the
transfer of energy
through empty
space
Conduction –
heat transfer by
direct contact of
particles of
matter
Convection & Convection
Currents
Heating and cooling of the fluid, changes in
the fluid’s density, and the force of gravity
combine to set convection currents in
motion.
Convection
– heat
transfer by
the
movement
of a heated
fluid
Convection
currents –
the flow
that
transfers
heat within
a fluid
Convection Currents in Earth
Heat from the core and the mantle causes
convection currents in the mantle. This is
how the heat is transferred, and how the
earth’s plates are able to move.
Plate Boundaries
At the locations where two tectonic plates interact,
a boundary between these plates exist. There
are three types of boundaries that geologist
observe. (Draw these pictures into your notes)
Plate Boundaries
There are three kinds of plate boundaries:
1. divergent boundaries – when the plates slide apart and create a rift
2. convergent boundaries – two plates collide
3. transform boundaries – when two plates slide past each other
A different type of plate movement occurs along each type of boundary.
The Continental Drift Theory
An hypothesis was created that all the continents were
once joined together in a single landmass.
Continental Drift Theory – The idea that the continents
slowly moved over Earth’s surface.
Scientists now believe that about 250 million
years ago, a super-continent known as Pangaea
existed. This super-continent was made up of all
the continents on Earth.
Evidence for Continental Drift
Fossils – any trace of an ancient organism that
has been preserved in rock.
Continental Drift
It has taken the continents about 225 million
years since the breakup of Pangaea to
move to their present locations.
Earth….100 Million Years
from Now
http://www.youtube.com/watch?feature=play
er_detailpage&v=uGcDed4xVD4
Plate Tectonics Review
1.
2.
3.
4.
Define Geology.
What does a geologist study?
How do constructive and destructive forces differ?
What are the 3 main layers of the Earth? Briefly describe
each layer.
5. What are plates, and how do they move?
6. What is heat transfer? What are the 3 ways in which heat
transfers?
7. What are plate boundaries ? What are the 3 types that
geologists observe? Briefly describe each type.
8. Explain the Continental Drift Theory.
9. What was Pangaea?
10. What evidence was there of this super-continent existing?