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The theory of Plate Tectonics

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The theory of Plate Tectonics ... Tectonic plates can move away from each other- allowing for new ocean floor to be formed. This area is called a divergent boundary. – PowerPoint PPT presentation

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Title: The theory of Plate Tectonics


1
The theory of Plate Tectonics
http//www.teachersdomain.org/resource/ess05.sci.e
ss.earthsys.plateintro/
2
A Voyage through Time Activity
  • Objectives To view the breakup of the
    super-continent Pangaea over the past 190 million
    years and chart the subsequent movement of
    landmasses, and to better understand plate
    tectonics.
  • (This lesson plan was adapted from a similar
    activity by Ford, 1994.)

http//www.youtube.com/watch?vbdeb7qGSnP4feature
related
3
  • Materials
  • Each pair of students will need
  • - a copy of the map sheets (on card stock for
    Figures 1A to 1E)
  • - colored pencils or crayons red, orange,
    yellow, green, blue, purple, tan
  • - scissors
  • - access to a world map showing terrain, such as
    mountains and seafloor

4
  • Beginning with frame 20 and working back-wards,
    have students identify the landmasses listed in
    the table below. Have group members color these
    landmasses as indicated in the table, assigning a
    different land mass to each student.
  • Have students continue working backwards through
    the frames until they can no longer identify the
    individual landmasses.

5
  • Land Masses Color
  • North and South America Yellow
  • Australia Tan
  • India Orange
  • Africa Green
  • Europe and Asia Red
  • Antarctica Blue
  • Greenland Purple

6
  • Have students cut out each frame carefully along
    the outside frame lines. When all rectangles are
    cut out, stack them in order 1-20. Frame 1 should
    be on top.
  • Holding the rectangles along their left side,
    have students flip through the frames, observing
    changing position of the landmasses (plate
    movement and continental drift). They are
    modeling the breakup of Pangea and the movement
    of landmasses over 190 million years, arriving at
    the configuration of our present-day continents.

7
  • Have students consider the following questions
  • 1. What event began to occur about 190 million
    years ago?
  • 2. During your coloring of the frames, in which
    frame did you locate the first appearance of the
    following landmasses
  • North America? Australia? Antarctica?
  • India? Europe?
  • 3. In which frame did you locate the final
    breakup of Pangaea? Why did you choose that frame
    and not another?
  • 4. Sometimes when two plates collide, the
    landmasses (continents) within the plates are
    pushed together and a mountain range can form.
    Using a world map, identify two locations where
    mountain ranges exist and where you hypothesize
    plate collisions between continents or parts of
    continents have occurred. Use your flipbooks to
    confirm your hypothesis. (Note that not all
    present-day mountain ranges were
  • formed by continental collision events or by
    plate convergence that occurred during the last
    190 million years.).

8
  • 5. If mountain ranges can form where plates are
    colliding, what would you hypothesize might occur
    where plates are separating? Apply your
    hypothesis to identify locations on a world map
    where plates might be separating (both oceanic
    and continental lithospheric plate divergence
    zones can be identified on the map and in the
    flip books). The
  • flipbooks will help you identify previous plate
    separations

9
Extension (3rd period only)
  • Using selected slides, identify and color India.
    You will be graphing the changing position of the
    India landmass (distance from the equator) using
    the scale and the approximate center of India.
  • Note the probable effects on climate through the
    past 100 million years as Indias position
    changed. How would the climate be different than
    the climate of India today?
  • Can you find any evidence that supports the
    concept of a different climate for India 100 or
    more million years ago? ( available in books or
    the Internet)
  • What other landmasses could you repeat this
    process with? Choose another one and compare it
    to India. Which moved a greater distance over
    time?

10
Wegeners Continental Drift Hypothesis
http//www.ucmp.berkeley.edu/geology/anim1.html
245 million years ago
In the early 1900s a scientist named Alfred
Wegener developed a hypothesis stating that the
continents once formed a single landmass called
Pangaea. (all earth) -hypothesis is known as
Continental Drift
http//www.youtube.com/watch?vOXhHNkC_VKcfeature
related
11
This hypothesis helped to explain why fossils of
plants and animals, along with matching rocks
(strata), have been found on both sides of the
Atlantic Ocean.
Example Applachain Mountains
And if the continents are put back to their
pre-drift locations the mountains form a
continuous chain.
12
(No Transcript)
13
Lystrosaurus - fossils of this little land
reptile were found in Africa, India, Argentina,
China and Antarctica!
Didnt have gills, fins or opposable thumbs
14
Glossopteris fossils of this tropical tree are
found in South America, Africa, India,
Australia and Antarctica!
15
If the continents had been together as Wegener
claimed, then the animals that became
fossils would have been living close together
and then been split apart as the continents
moved.
16
Other pieces of evidence used to support the
Theory of Continental Drift
  • Coal distribution
  • -coal forms in warm, wet climates, but has
    been found under the cold, dry Antarctic ice.
    This could means that Antarctica was once
    connected with the other continents and was once
    in a warm and humid region.
  • The coastlines of Africa
  • and South America appear
  • to fit together as though
  • pieces of a large puzzle.

17
We find evidence of glaciers along the equator
(the warmest area of the planet)
18
and fossils of tropical rain forests in New
Brunswick, northern Canada and northern Europe
19
Again, it doesnt make much sense unless the
continents are moved back to their pre-drift
location.
now the glaciers are near the pole and the palm
trees are on the equator.
20
A Plate Tectonics Puzzle
By examining evidence such as similar rock layers
in various places, fossilized desert belts, the
distribution of fossils and the physical shapes
of continents, scientist have concluded that the
Earths continents were once all connected to
forma supercontinent called Pangaea that was
surrounded by an enormous ocean. In this
activity, you will use the different kinds of
evidence to reconstruct how the Earth may have
looked approximately 220 million years ago.
21
MATERIALS Globe or world map student answer
sheet Instructions and cutout pages scissors Glue
or tape sheet of construction paper
  • PROCEDURES
  • Cut out the landmasses.
  • Using the legend on the on the globe answer
    sheet, identify
  • what each symbol represents
  • 3. You will use the evidence (symbols) on the
    continents and islands to reconstruct Pangaea.
    Use the globe or a world map as a reference.
    Remember that most of the landmasses were around
    the equator (warm and humid regions)
  • 4. Use the physical shape of the continents,
    fossilized desert belts, and the ditribution of
    fossils to fit the continents and islands
    together. (NOTE not all boundaries will be
    touching-there might be area of water separating
    them)

22
  • 5. Once you are sure of your placement of the
    landmasses, tape or glue them down onto the world
    map.
  • 6. Label it PANGAEA. Put your names and class
    period on the top.
  • 7. Compare your world map with another group. Is
    theirs different? In what way?
  • 8. What evidence led you to your decision for the
    placement of the continents?

http//www.brainpop.com/science/earthsystem/platet
ectonics/ -Plate tectonics Brainpop and
worksheet
23
Pangaea Puzzle
  • Materials (per pair of students/group)
  • - ½ potato (cut lengthwise) -plastic knife
  • -sharpie -lab notebook
  • Procedures
  • Each group will cut the potato into 8 pieces
    according to the diagram.
  • Remove the meat from the potato, careful not to
    damage the potato skin.
  • Put the potato pieces back together. Can you
    still form a potato?
  • Answer the conclusion questions in your lab
    notebook

24
Plate Tectonics The theory that states large
pieces of Earths lithosphere move around (or
float) on the asthenosphere.
There are 3 types of tectonic plate boundaries
http//www.youtube.com/watch?vdkELENdZukIfeature
related
-plate boundary rap
25
Convergent Zone Tectonic plates can collide into
each other. This is called a convergent boundary.
With this type of boundary you will have either a
collision of plates-forming mountains
or A destruction of plates at a subduction zone
Example Indian Plate and Eurasian Plate forming
the Himalayas
http//www.youtube.com/watch?NR1featureendscree
nvxL6sKtG2UVs
26
collision
Three types of convergent boundaries Continental
-Continental Oceanic-Continental Oceanic-Ocea
nic
destruction
Produces a subduction zone, where the lithosphere
is sliding back into the mantle.
27
What type of convergent boundaries are these?
  1. ______________
  2. _______________
  3. _______________

Continental-Oceanic
Oceanic-Oceanic
Continental-Continental
28
Tectonic plates can move away from each other-
allowing for new ocean floor to be formed. This
area is called a divergent boundary.
This boundary type is constructive
mid-ocean ridge underwater mountain chain that
runs through the Earths ocean ridges -places
where seafloor spreading occurs
Example
Seafloor spreading the process in which magma
rises, solidifies and forms new ocean
floors. -as new magma rises, the older ocean
crust is pushed further away from the ridge.
29
The last boundary occurs when tectonic plates
slide past each other. This is called a
transverse or transform boundary. Example
North American and Pacific plates along the San
Andreas Fault
This boundary type is conservative-land is
neither made nor destroyed
30
Seafloor Spreading activity
Part 1 Just the Facts! Use the data below and
write the age of the sediments found at each site
on the map below. (Write the age on the line by
each site.) Then answer the conclusion questions
on the data sheet.
site Age of sediments (in millions of years) Distance from the ridge (in km)
14 40 745
15 24 422
16 11 221
17 33 718
18 26 506
19 49 1010
20 67 1303
21 gt76 1686
31
(No Transcript)
32
  • Conclusions (Please write in complete
    sentences!)
  • Where are the youngest sediments found, compared
    to the Mid-Atlantic Ridge?
  • __________________________________________________
    __________________________________________________
    ____________
  • 2. Where are the oldest sediments found?
  • __________________________________________________
    __________________________________________________
    ____________
  • 3. Does the data support the theory of sea floor
    spreading? How?
  • __________________________________________________
    ______
  • __________________________________________________
    ______

33
Seafloor Spreading activity
Materials Base (Construction paper), Templates
for plates, Scissors, Tape Directions 1. Cut out
the strips representing the North American Plate
and the Eurasian Plate. Place them face to face
(letters on the inside) with the number 1 at the
top. 2. Use a small piece of tape to attach the
two strips at the bottom edge (by the number
7). 3. Insert the attached strips into the slot
in the middle of the base, from the bottom. 4.
Feed one strip into slot A and the other into
slot C. (See diagram) 5. Push the strips up from
below the base until you can see the numbers 3,
4 and 5 on the top. 6. Answer the conclusion
questions
34
Seafloor Spreading activity
4. What are you modeling by pushing the strips up
through the base? ________________________________
__________________________________________________
__________________________________________________
________ 5. What is being modeled at slits A and
C as you push the strips up through the
base? ____________________________________________
__________________________________________________
______________________________________________ 6.
This model shows what happens at sea floor
spreading centers, such as the mid-Atlantic
Ridge. List at least 2 good points of this
model. ___________________________________________
__________________________________________________
______________________________________________ 7.
What are at least 2 reasons why this model is not
a good model? ____________________________________
__________________________________________________
__________________________________________________
____ 8. Seafloor spreading is continuing today
along mid-ocean ridges such as the Mid-Atlantic
Ridge. Predict what effect this will have on the
size of the ocean basin _________________________
__________________________________________________
__________________________________________________
__________________________________________________
__________________________________________________
__________________________________________________
_____
35
http//www.youtube.com/watch?NR1featureendscree
nvifke1GsjNN0
Now its your turn! How well do you know the
difference between the boundaries between the
plates
http//www.youtube.com/watch?v3qsaVtPOBXM
36
Three Possible Explanations for Plate
Tectonics -each can occur from the heating
and cooling of rock when hot, a rock is less
dense and will rise.
37
Magma close to the core heats up and rises
Magma sinks, plates are dragged towards each
other
Magma spreads out, plates move apart
38
Convection Current mini lab
  • Materials
  • computer paper square (6 cm)
  • tissue paper square (6cm)
  • aluminum foil square (6cm)
  • thread (15-20 cm)
  • heat source

39
Procedures
  • Chose 1 type of paper square
  • Write a hypothesis-what do you think will happen?
  • Using a pair of scissors, cut your square
  • 4. Poke a small hole in one end, pull a piece of
    knotted thread through the hole
  • 5. Have a teacher to light your candle
  • 6. Hold your paper spiral by the thread about 10
    cm above the flame! ( DO NOT let the paper touch
    the flame)

40
Conclusion Questions
  • What happens? Explain why
  • How can this be related to plate tectonics?

41
100 Greatest Discoveries with Bill Nye!!!
  • http//player.discoveryeducation.com/index.cfm?gui
    dAssetIde936d178-9d65-4ce6-886f-e10c84062305

42
Classwork Assignment
A Moving Jigsaw Puzzle worksheet -label each
picture as either a convergent, divergent or
transverse boundary
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