Transcript internal forces shaping the earth

INTERNAL FORCES
THAT SHAPE THE EARTH
Chp. 2 Section 3
Learning goal:
• Explain plate tectonics and the
effects they have on our planet
Continental Drift Theory
• All continents had
once been joined
together in a supercontinent called
Pangaea, but slowly
drifted apart.
• Evidence: the same
crocodile fossils were
found in Brazil and
South Africa
• Evidence: continents
can fit together like
puzzle pieces
Plate Tectonics
• Tectonic
plates=enormous
moving pieces of
the earth’s
lithosphere
• Continents split
apart due to the
movements of
tectonic plates
4 Types of
Plate
Movement
http://earthquake.usgs.gov/learn/animations/animation.php?flash_title=Divergent+Boundary&flash_file=divergent&flas
h_width=500&flash_height=200
1. Diverging
Plates spread apart
*The space between is filled with magma, which
forms underwater mountain ranges
An effect of divergent plate movement is
a…VOLCANO!
Ring of Fire: zone around the Pacific plate
known for multiple volcanic
eruptions/earthquakes
2. Convergent :Subduction
One plate moving under another
* “sub”=under, like submarine
http://earthguide.ucsd.edu/eoc/teachers/t_te
ctonics/p_subduction.html
3. Convergent: Collision
Plates come together
* “con”=to come together like
“con”vention
*When the plates collide, they
create large mountain ranges like
the Himalayas.
World’s
tallest:
Mount
Everest
4) Transformation
Plates slide past one
another
• When plates slide past one another
at a fault, like the San Andreas, it can
cause an earthquake
• Fault= crack/joint in the earth
Earthquakes
• Caused when tectonic plates grind or slip
• Richter Scale: scale that rates earthquakes
(1=10)
Tsunamis
• BBC NEWS
| World |
The tsunami
disaster
explained
A giant
wave
caused by
an
earthquake
on the
ocean
floor.
Create a newspaper article!
• Pick an event: earthquake, volcano eruption,
tsunami…Can be more than one! (i.e. earthquake
& tsunami)
• Explain exactly what happened. Be specific! Tell
where this happened, tell what type of
plate movement it was and explain
how those plates move, explain the
damage of the disaster.
• Draw a picture to explain how this happened
(plate movement arrows) and a picture of the
damage it caused.
External
Forces
Shaping the
Earth
Chp. 2 Section 4
Learning Goal:
• Describe mechanical and chemical
weathering.
• Explain how water, wind, and glaciers affect
the development of landforms
• Identify the basic components of soil
Weathering
Processes that change the
characteristics of rocks.
Mechanical Weathering
• Processes that break rock into
smaller pieces.
• Does not change composition of
rock—just its size
Chemical Weathering
• When composition of
rock is changed due to
elements in the water
and air which
decompose the rock
• Ex: when iron rusts
Erosion= wearing away of rock, land or
soil by wind, water, ice or gravity
Water Erosion
• One form of water
erosion occurs when
water flows in a stream
or river
• When a river enters the
ocean, the sediment it
picked up during flow is
deposited in a fan-like
landform called a delta
Wind Erosion
• The wind picks up and
transports sediment in
different locations
• Deposits of loess, or wind
blown silt or clay, are
found across the world.
Glacial Erosion
• Glaciation is the
changing of
landforms by
slowly moving
glaciers
Article Title
Author
Draw a picture to
explain how this
happened
(illustrate the plate
movements)
Draw a picture of the
damage it caused
Keep it appropriate…
Caption explaining the
above picture
Date
• Pick an event: earthquake,
volcano eruption,
tsunami…Can be more than
one! (i.e. earthquake &
tsunami)
• Explain exactly what
happened. Be specific! Tell
where this happened, tell
what type of plate
movement it was and
explain how those plates
moved, explain the damage
of the disaster.
• At least 10 sentences, be
creative but still cover the
content!