IC Lessons Plate Tectonics
This is lesson _2_ of _4_ in this IC
A. Title of this lesson: Sea Floor Spreading
B. Summary of this lesson
Work in Progress
C. Objective(s)/Learning Goal(s)/ Key Student Learning(s) of this lesson
Students will be able to argue from evidence in support of continental drift.
• Students describe the seafloor spreading hypothesis
• Explain the moving pieces of the lithosphere
• Recognize subduction
D. Teacher Background Knowledge for this lesson
Sea Floor Spreading USGS
The process of sea-floor spreading created the lithosphere under the Atlantic Ocean. As North
America and South America moved away from Europe and Africa, the resulting crack was filled by
mantle material, which cooled and formed new lithosphere. The process continues today. Molten
mantle materials continually rise to fill the cracks formed as the plates move slowly apart from each
other. This process creates an underwater mountain chain, known as a mid-ocean ridge, along the
zone of newly forming lithosphere.
Magnetic Stripes
Molten rock erupts along a mid-ocean ridge, then cools and freezes to become solid rock. The
direction of the magnetic field of the Earth at the time the rock cools is "frozen" in place. This
happens because magnetic minerals in the molten rock are free to rotate so that they are aligned
with the Earth's magnetic field. After the molten rock cools to a solid, these minerals can no longer
rotate freely. At irregular intervals, averaging about 200-thousand years, the Earth's magnetic field
reverses. The end of a compass needle that today points to the north will instead point to the south
after the next reversal. The oceanic plates act as a giant tape recorder, preserving in their magnetic
minerals the orientation of the magnetic field present at the time of their creation. Geologists call
the current orientation "normal" and the opposite orientation "reversed."
In the figure below, two plates are moving apart. A mid-ocean ridge marks the location where
molten rocks are moving up, cooling, and forming new ocean floor. The zones of normal
magnetization are indicated by ////// shading of the oceanic crust.
Created by San Lorenzo USD Teachers: Julie Ramirez, Veenu Soni, Marilyn Stewart, and Lawrence Yano
(2012)
IC Lessons Plate Tectonics
This is lesson _2_ of _4_ in this IC
The figure below shows the observed magnetic pattern along the mid-Atlantic Ridge south of
Iceland. This figure is from the excellent publication "A Teacher's Guide to the Geology of Hawaii
Volcanoes National Park" (Mattox, 1992), which is available on the World Wide Web at
http://volcano.und.nodak.edu/vwdocs/vwlessons/plate_tectonics/part9.html. The Guide starts at
http://volcano.und.nodak.edu/vwdocs/vwlessons/atg.html .
Created by San Lorenzo USD Teachers: Julie Ramirez, Veenu Soni, Marilyn Stewart, and Lawrence Yano
(2012)
IC Lessons Plate Tectonics
This is lesson _2_ of _4_ in this IC
Based on the pattern and spacing of the oceanic magnetic stripes and the inferred motion of the
plates, the age of the ocean floor can be determined. In the figure below by Müller and others
(1997) ( http://gdcinfo.agg.emr.ca/app/jgr_paper.html ), the age of the ocean floor is depicted by
colors (http://gdcinfo.agg.emr.ca/app/images/agemap.GIF ).
Created by San Lorenzo USD Teachers: Julie Ramirez, Veenu Soni, Marilyn Stewart, and Lawrence Yano
(2012)
IC Lessons Plate Tectonics
This is lesson _2_ of _4_ in this IC
E. Prior knowledge that students need to understand this lesson - with an assessment to
determine what they already know (if appropriate).
Work in Progress
F. Standards covered in this lesson
Current California Science Standard
1c. Describe the sea-floor spreading hypothesis.
7e Recognize whether evidence is consistent with a proposed explanation
7g Interpret events by sequence and time from natural phenomena
NGSS
Created by San Lorenzo USD Teachers: Julie Ramirez, Veenu Soni, Marilyn Stewart, and Lawrence Yano
(2012)
IC Lessons Plate Tectonics
This is lesson _2_ of _4_ in this IC
4. Analyzing and interpreting data
7. Engaging in argument from evidence
8. Obtaining, evaluating, and communicating information
CCSS that apply
Reading
Work in Progress
Writing
Work in Progress
Listening & Speaking:
Work in Progress
Math
Work in Progress
G.
Suggested time to complete this lesson
Two 50 minute periods
H. Materials Used in this lesson typed in a bulleted list with quantities (e.g., 10 beakers; water
– 2 liters)
video of Hess and his discoveries
http://pubs.usgs.gov/of/1999/ofr-99-0132/
Created by San Lorenzo USD Teachers: Julie Ramirez, Veenu Soni, Marilyn Stewart, and Lawrence Yano
(2012)
IC Lessons Plate Tectonics
This is lesson _2_ of _4_ in this IC
I. Materials Prep for this lesson
Work in Progress
J. Lesson Plan – detailed, numbered step-by-step plans.
DAY 2 Sea Floor Spreading Part 1
Ask students to talk to their elbow partner and remind each other who
Wegener was. Have students call out what they remember.
Ask students how Wegener must have felt when people did not support
Wegener?
What did other scientists have issues with?
What did Hess contribute to what Wegener believed?
Show a video of Hess and his discoveries.
http://pubs.usgs.gov/of/1999/ofr-99-0132/
DAY 2 Sea Floor Spreading - Part 2
Teacher background: Students may need clarification about the magnetic pole
reversals. We showed the Bill Nye Video and demonstrated how the poles
reverse using a model. We purchased (on-line) a “Steric Demonstrator of
Magnetic Line –of-Force” model to show the existence of the magnetic fields
and the spatial distribution of it line-of-force.
http://www.opentip.com/popup_image.php?pID=3923875&imgName=MEP-7503.jpg
Yesterday we talked about Harry Hess and his theory of seafloor spreading.
What important discoveries did Hess and his fellow scientists make? (Review
the chart from Day 1 and Day 2 Part 1)
Created by San Lorenzo USD Teachers: Julie Ramirez, Veenu Soni, Marilyn Stewart, and Lawrence Yano
(2012)
IC Lessons Plate Tectonics
This is lesson _2_ of _4_ in this IC
Expected Student Responses:
•Continuous chain of undersea mountains known as the mid-ocean ridge
•Symmetrical patterns of magnetic reversals shown by metal crystals
embedded in rocks
•Rocks that were farther away from ridge were older (age of rocks)
So, we have learned that scientists often use models to explain their thinking.
We have used globes, maps, diagrams; charts etc. when size or safety issues
keep us from viewing the real thing. So today we are going to consider how we
might make a model that would explain or demonstrate sea floor spreading.
Think Pair Share: Turn and talk to your elbow partner: If you were making a
model of sea-floor spreading what are the important ideas that are associated
with seafloor spreading? Share out.
Expected student answers:
•The mid-ocean ridge
•Symmetrical magnetic patterns
•Age of rocks
Here is a worksheet that students may use to write their thoughts on: (see
attached lab sheet)
You have come up with some important ideas that need to be included. (If any
parts are missing, ask “What about _______________ do you think this should
be included?”)
“Today we are going to create a model that I hope will incorporate all of your
important points.”
Created by San Lorenzo USD Teachers: Julie Ramirez, Veenu Soni, Marilyn Stewart, and Lawrence Yano
(2012)
IC Lessons Plate Tectonics
This is lesson _2_ of _4_ in this IC
Students will make their own models and replicate. Have students sit in groups
of four, but work in pairs.
1. “Your group is your research base. Although you will do the actual work of
creating the model in pairs, you will discuss, analyze and share out with your
group.”
2. Assign jobs:
• Paper Manager—Pulls out the strip and marks the paper
• Technical Advisor: Sets up and reads compass/flips the magnet
(For the lab, A’s and C’s are Paper Managers, B’s and D’s are Technical
Advisors).
The following directions have many steps. Since they are pulling, marking,
flipping etc. we recommend the teacher demonstrates how to create the model
by showing at least 2 examples of magnetic reversals.
3. Paper Manager - Fold the strip of paper in half. Take the ends of paper and
slip them up between two tables, leaving the folded end of the paper below the
table.
4. Technical Advisor Place compass about 2 inches above the area where the
paper will come out. Place the magnet, just below it. Take a reading from the
compass and note which direction is North.
5. Paper Manager slowly pulls the strips of paper up and apart about 2 inches on
either side of the opening between the two tables. Use the marker to draw
along the space between the two tables to register the end of the first magnetic
pattern. Make sure the marker marks both sides of the paper
6. Technical Advisor Advise the manage where to mark North, at the top of the
paper or at the bottom.
7. Paper Manager: Label North and Draw arrows in the direction of north for
that section; mark it “Section A”.
Created by San Lorenzo USD Teachers: Julie Ramirez, Veenu Soni, Marilyn Stewart, and Lawrence Yano
(2012)
IC Lessons Plate Tectonics
This is lesson _2_ of _4_ in this IC
8. Technical Advisor Repeat Step 4 to 7 with these modifications. Paper
Manager: Use varying lengths when you pull out the paper. (ex. 1st time = 2
inches, 2nd time = 1 inch, 3rd time = 2 inches, 4th time = 3 inches, 5th time = 1
inch). Use a different color marker each time you draw the arrows. Label each
new section B, C, etc. until you come to the end of the paper. Technical Advisor:
Be sure to flip the magnet each time you begin a new section.
9. Student C: Color the center folds a bright color. Remove the tape and use the
completed model to discuss and analyze with your group.
When you have completed the model, discuss the following questions together
and jot down your thinking about at the each.
Looking at Parts of the Model
1) What does the paper strip used in the model represent in real life?
2) Where the strips of paper met and you drew a line, what does that
represent?
3) When the strips of paper are pulled out, what process does this
represent?
4) What does the magnet represent?
5) Why do you think we marked the sections, A, B, C, etc.? What could we
use these sections to explain?
6) What do the sections with arrows represent? (Why are they pointing in
different directions)?
7) Why was it important to flip the magnet before we pulled out the paper
strip?
8) Did we include all the important elements needed to explain seafloor
spreading? If yes, what are they? If no, what is missing?
9) Can you think of a way that we could add/delete/change items that
would make this model more effective?
10)
Can you think of a way that we could use this model to explain
Wegener’s idea of Continental Drift?
Created by San Lorenzo USD Teachers: Julie Ramirez, Veenu Soni, Marilyn Stewart, and Lawrence Yano
(2012)
IC Lessons Plate Tectonics
This is lesson _2_ of _4_ in this IC
Exit Ticket: What evidence does sea-floor spreading provide to support
Wegener’s idea of Continental Drift?
K. Vocabulary words – key vocabulary words that are targeted or taught as part of the lesson.
(Understanding these words is essential for students to understand the key concepts of this
lesson.)
Work in Progress
L. Potential Pitfalls for: a. student understanding; b. laboratory mishaps and common
procedural errors; c. academic vocabulary issues, etc.
Work in Progress
M. Differentiation: Modifications for English Learners, advanced learners, struggling learners,
etc.
Work in Progress
N. Please list all worksheets used in this lesson.
Making a model of Sea-floor Spreading (See attached)
O. Please list all assessments that require a separate sheet.
SUMMATIVE ASSESSMENT: RERUN
Recall: Summarize what you did in the Pangaea Activity
Explain: Explain the purpose of the Activity.
Results: What were the results of the activity?
Uncertainties: after doing this activity what are you still unsure of?
New: List at least two new things that you learned from this activity.
P. Photos/Illustrations
Created by San Lorenzo USD Teachers: Julie Ramirez, Veenu Soni, Marilyn Stewart, and Lawrence Yano
(2012)
IC Lessons Plate Tectonics
This is lesson _2_ of _4_ in this IC
N/A
Q. Other Resources
N/A
Created by San Lorenzo USD Teachers: Julie Ramirez, Veenu Soni, Marilyn Stewart, and Lawrence Yano
(2012)
IC Lessons Plate Tectonics
This is lesson _2_ of _4_ in this IC
NAME__________________________________DATE________________________PERIOD________
Making a model of Sea-floor Spreading
A. Quick write: Think of a model that you have used or seen this year that explains a scientific
concept. What was it trying to explain and what was included to help make that explanation?
______________________________________________________________________________________________________________________
______________________________________________________________________________________________________________________
__________________________________________________________________________________________________________
B. THINK -PAIR-SHARE: If you were making a model of sea-floor spreading, what do you think
would be important to include?
______________________________________________________________________________________________________________________
______________________________________________________________________________________________________________________
______________________________________________________________________________________________________________________
______________________________________________________________________________________________________
Materials: 24-in strip adding machine paper strip, box of markers, compass, magnet
Directions:
1. Your group is your research base. Although you will do the actual work of creating the model in
pairs, you will discuss, analyze and share out with your group
2. Assigned jobs:
 Paper Manager—Pulls out the strip and marks the paper
 Technical Advisor: Sets up and reads compass/flips the magnet
(For today’s lab, A’s and C’s are Paper Managers, B’s and D’s are Technical Advisors)
3.
4.
5.
6.
7.
8.
Paper Manager - Fold the strip of paper in half. Take the ends of paper and slip them up between
two tables, leaving the folded end of the paper below the table.
Technical Advisor Place compass about 2 inches above the area where the paper will come out.
Place the magnet, just below it. Take a reading from the compass and note which direction is
North.
Paper Manager Slowly pull the strips of paper up and apart about 2 inches on either side of the
opening between the two tables. Use the marker to draw along the space between the two tables
to register the end of the first magnetic pattern. Make sure the marker marks both sides of the
paper
Technical Advisor Advise the manage where to mark North, at the top of the paper or at the
bottom.
Paper Manager: Label North and Draw arrows in the direction of north for that section;, mark it
“Section A”.
Technical Advisor Repeat Step 4 to 7 with these modifications. Paper Manager: Use varying
lengths when you pull out the paper. (ex. 1st time = 2 inches, 2nd time = 1 inch, 3rd time = 2 inches,
4th time = 3 inches, 5th time = 1 inch). Use a different color marker each time you draw the arrows.
Label each new section B, C, etc. until you come to the end of the paper. Technical Advisor:
Be sure to flip the magnet each time you begin a new section.
Created by San Lorenzo USD Teachers: Julie Ramirez, Veenu Soni, Marilyn Stewart, and Lawrence Yano
(2012)
IC Lessons Plate Tectonics
This is lesson _2_ of _4_ in this IC
9. Student C: Color the center folds a bright color. Remove the tape and use the completed model to
discuss and analyze with your group.
When you have completed the model, discuss the following questions together and jot down your
thinking about at the each.
Looking at Parts of the Model
1.
What does the paper strip used in the model represent in real life?
2.
Where the strips of paper met and you drew a line, what does that represent?
3. When the strips of paper are pulled out, what process does this represent?
4. What does the magnet represent?
5. Why do you think we marked the sections, A, B, C, etc.? What could we use these sections to
explain?
6. What do the sections with arrows represent? (Why are they pointing in different directions)?
7. Why was it important to flip the magnet before we pulled out the paper strip?
8. Did we include all the important elements needed to explain seafloor spreading? If yes, what are
they? If no, what is missing?
9. Can you think of a way that we could add/delete/change items that would make this model more
effective?
10. Can you think of a way that we could use this model to explain Wegener’s idea of Continental
Drift?
11.
On the sketch of the sea-floor below 1) label the current mid-ocean ridge, 2) use arrows to
show the direction the sea-floor is moving and 3) draw in some magnetic patterns
Created by San Lorenzo USD Teachers: Julie Ramirez, Veenu Soni, Marilyn Stewart, and Lawrence Yano
(2012)
IC Lessons Plate Tectonics
This is lesson _2_ of _4_ in this IC
Created by San Lorenzo USD Teachers: Julie Ramirez, Veenu Soni, Marilyn Stewart, and Lawrence Yano
(2012)