1. Thursday 11/30/17
Notebook Entry: Look at the image below. What do you think the image is showing you? What do you think the different colors are supposed to tell you?

2. What other evidence could support Wegener’s idea
The ocean floor gives us many clues…how did we find these clues?
Marie Tharp’s Maps
Mapping with Sonar

3. Map of the Earth’s Mid-Ocean Ridges

4. Scientists Build on Previous Ideas
Harry Hess
Geologist and Navy submarine commander during World War II
In 1960 he proposed sea-floor spreading based on observations of the East Pacific Rise

5. East Pacific Rise

6. SEA-FLOOR SPREADING
Process by which molten material adds new oceanic crust to the ocean floor.
Occurs along a mid-ocean ridge.
Where are the mid-ocean ridges on your map?
Older oceanic crust moves away from ridge.

7. Sea-Floor Spreading at Mid-Ocean Ridge

9. Subduction
When ocean crust meets less dense rock in the crust it sinks below the less dense rock because of gravity
Forms a deep-ocean trench = a place where ocean crust bends downwards.
Where would the deep-ocean trenches be on the map?

10. Subduction at Deep Ocean Trench

11. What is a model? A model is a representation of something else.
Can show an object or process
Models help us to understand how the real things work
The model may look like, function like, describe, or explain the real thing.

12. Modeling Sea-Floor Spreading
How does sea-floor spreading add material to the ocean floor and what happens to this material over time?
Goal = Model sea-floor spreading and subduction along with the key landforms these two processes create.

13. Putting your model together…

14. Procedure START MYA 180 MYA 160 MYA 140 MYA 110 MYA 90 MYA 60 MYA
Fold the paper in half lengthwise and write the word “Start” at the top of each half of the paper.
Use the ruler and pencils to draw and color stripes across the paper. The stripes should look like the picture to the right.
In each stripe write the age of the crust as also shown in the picture (MYA = million years ago)
Using the scissors, carefully cut the paper in half along the fold line to form two strips.

15. Procedure
Following Mrs. Burke fold the second sheet of paper crosswise into eighths as shown. Then unfold it, leaving creases in the paper.
Now fold the second sheet of paper in half crosswise.
Starting at the center fold, draw lines 5.5 cm long on the middle crease

16. Procedure
Repeat the 5.5 cm line on the two creases closest to the ends of the paper.
Raise your hand so Mrs. Burke can check your lines.
Carefully cut along the lines you drew. Unfold the paper. There should be three slits, each 11 cm long, in the center of the paper as shown below.

17. Homework
Read and do pages 84-85
I will be checking your textbook tomorrow for completion of the reading pgs

18. Friday 12/1/17
Notebook Entry: Look at the picture below. Describe how convection in the mantle could cause sea-floor spreading?

19. Procedure START MYA 180 MYA 160 MYA 140 MYA 110 MYA 90 MYA 60 MYA
Fold the paper in half lengthwise and write the word “Start” at the top of each half of the paper.
Use the ruler and pencils to draw and color stripes across the paper. The stripes should look like the picture to the right.
In each stripe write the age of the crust as also shown in the picture (MYA = million years ago)
Using the scissors, carefully cut the paper in half along the fold line to form two strips.

20. Putting your model together…

21. Turn in the question sheet when done. One team member keeps the model.
Analyze and Conclude Questions
We will work together and use our textbook to help us analyze our model.
Turn in the question sheet when done.
One team member keeps the model.

22. Sea-Floor Spreading & Subduction

23. SEA-FLOOR SPREADING
Process by which molten material adds new oceanic crust to the ocean floor.
Occurs along a mid-ocean ridge.
Older oceanic crust moves away from ridge.

24. Sea-Floor Spreading Sea-Floor Spreading
Some mid-ocean ridges have a valley that runs along their center. Evidence shows that molten material erupts through this valley and then hardens to form the ocean floor.

25. Deep-Ocean Trenches The deepest part of
Sea-Floor Spreading
Deep-Ocean Trenches
The deepest part of
the ocean is along the Mariana Trench. Several trenches in the Pacific Ocean are shown in yellow.

26. Subduction
When ocean crust meets less dense rock in the crust it sinks below the less dense rock because of gravity
Ocean crust is more dense rock when compared to continental crust
Forms a deep-ocean trench = a place where ocean crust bends downwards.
Where would the deep-ocean trenches be on the map?

27. Vocabulary Card Assignment
Due Tuesday 12/5/17
Make cards for the following terms:
Continental Drift
Sea-floor spreading
Subduction
Remember to copy definition from your textbook.
Use your book to help you with completing your card.