Download Plate tectonics explains the movement of large

8 Planets
Electromagnetic waves
• Produced by the movement of
electrically charged particles
• Can travel in a “vacuum” (they do
NOT need a medium
• Travel at the speed of
light
Examples from Space!
Radio waves
• Longest wavelength EM waves
• Uses:
– TV broadcasting
– AM and FM broadcast radio
– Avalanche beacons
– Heart rate monitors
– Cell phone communication
Microwaves
• Wavelengths from 1 mm- 1 m
• Uses:
– Microwave ovens
– Bluetooth headsets
– Broadband Wireless Internet
– Radar
– GPS
Infrared Radiation
• Wavelengths in between microwaves and
visible light
• Uses:
– Night vision goggles
– Remote controls
– Heat-seeking missiles
Visible light
• Only type of EM wave able to be detected
by the human eye
• Violet is the highest frequency light
• Red light is the lowest frequency light
Ultraviolet
• Shorter wavelengths than visible light
• Uses:
– Black lights
– Sterilizing medical equipment
– Water disinfection
– Security images on money
X-rays
• Tiny wavelength, high
energy waves
• Uses:
– Medical imaging
– Airport security
– Inspecting industrial welds
Gamma Rays
• Smallest wavelengths, highest energy EM
waves
• Uses
– Food irradiation
– Cancer treatment
– Treating wood flooring
Changes in the Earth over time
Changes in the Earth over time
Weathering- the process of rocks being broken
down into smaller pieces.
Two types of Weathering
Mechanical
Rocks break into
smaller pieces by
physical means –
Water, ice, wind, gravity,
organisms &
changing
temperatures
Chemical
Rocks break into smaller
pieces by chemical
reactions – Air, water,
acid & salts react with
minerals in rocks to
form new substances
Erosion
Destructive
• The movement of particles
from one location to another
is erosion
• Weathered particles of rock
are transported by gravity,
living organisms, water,
glaciers & wind.
Deposition
Constructive
• The settling (depositing) of eroded
particles as sediments wherever they are
transported by wind or water.
Rock Cycle
Plate Tectonics
Plate Tectonics
Plate tectonics explains the movement of large
sections of Earth’s crust called tectonic plates. The
force behind tectonic plate movement is thought to be
currents of magma flowing in Earth’s mantle.
What is Plate Tectonics
• The Earth’s crust and upper
mantle are broken into
sections called plates
• Plates move around on top of
the mantle like rafts
Why do the plates move?
1. Due to tremendous heat, rock in the
asthenosphere is like hot taffy
2. This allows plates to ride on top of hot,
flowing rock.
3. Plates move because heat is being
released from deep inside the earth.
4. Convection currents causes hot material
to rise and expand (plates diverge) and
cooler material to sink and contract
(plates converge).
What is the Lithosphere?
• The crust and part of the upper
mantle = lithosphere
–100 km thick
–Less dense than the material
below it so it “floats”
What is the Asthenoshere?
• The plastic layer below the
lithosphere = asthenosphere
• The plates of the lithosphere
float on the asthenosphere
Plate boundaries
Tectonic plates slowly collide against one another along
plate boundaries. Sections of the plates may break off
and be pushed down, up, or to the side. Mountain
ranges, ocean trenches, earthquakes & volcanic activity
are all common along plate boundaries.
Pacific Plate
is the largest
Convergent Boundaries
• Boundaries between two
plates that are colliding
 
• There are 3 types…
Type 1
• Ocean plate colliding with a
less dense continental plate
• Subduction Zone: where the
more dense plate sinks under
the less dense plate
• VOLCANOES occur at
subduction zones
Andes Mountains,
South America
Type 2
• Ocean plate colliding with
another ocean plate
• The more dense plate sinks
under the more dense plate
creating a subduction zone
called a TRENCH
Type 3
• A continental plate colliding
with another continental plate
• Have Collision Zones:
–a place where they are folded
and thrust upward to form
mountains.
Divergent Boundaries
• Boundary between two plates
that are moving apart or rifting

• RIFTING causes SEAFLOOR
SPREADING
Features of Divergent
Boundaries
• Mid-ocean ridges
• rift valleys
• fissure volcanoes
2 Types of Plates
• Ocean plates - plates below
the oceans, which is more
dense
• Continental plates - plates
below the continents, which is
less dense
Alfred Wegener
Alfred Wegener – proposed that in the distant
past, the Earth’s continents were all joined as a
single landmass.
1. Evidence for his theory
a. South America and Africa would fit
remarkably well, shoreline to shoreline.
b. If the Americas were moved next to Africa
and Europe, there would be a match of
ancient continental rocks and tectonic (fold
and fault) structures.
c. Pangaea – when Wegener placed all the
continents together like a puzzle, it formed
a large landmass which he called Pangaea.
Continental Drift – states that the continents
have drifted and still are drifting apart.
Strong support for
this hypothesis
comes from fossils
found in South
America and Africa
which indicate that
the regions had
similar animal and
plant life. And
tropical fossils
were found in
Antarctica that
existed around 200
million years ago.
Plus, the
contintents fit like
puzzle pieces.
Fossil Evidence
All the land that
drains into a
specific body of
water.
Groundwater and
surface water
both contribute
to the water in a
watershed.
Surface water
becomes
groundwater by
soaking into the
sand and soil or
by traveling
through cracks
in rock.