1. Name: Date: Tuesday 12/1/15 Topic – Ch4L2 – Development of a Theory (Pages 134-141)
Essential Question (SC.7.E.6.2, SC.7.E.6.4, SC.7.E.6.7)
How is the seafloor spreading?
Student Objective I can explain how there is evidence for seafloor spreading
I Do/We Do – Guided notes and Class discussion
You/Do – Student/Teacher choice menu
Do Now
Do Lesson 1 Review on pg 132
Think about it on pg 134

2. Development of a Theory

3. After world war 2, we were able to explore the seafloor
Remember how much of the evidence for continental drift was on the seafloor?
After world war 2, we were able to explore the seafloor
Done using an echo sounder
A topographic map was able to be made this way
Echo sounding allowed us to see giant mountains below the ocean’s surface
Mid-ocean ridge: mountain ranges that are in the middle of the ocean
much larger than those on land

4. Seafloor spreading
Seafloor spreading: the process where new oceanic crust forms along a mid-ocean ridge and older oceanic crust moves away from the ridge
Done in the 1960’s
Helped to explain continental drift better than Wegner’s explanation

5. Seafloor spreading
Basalt is formed when lava erupts and cools at the mid-ocean ridge on the ocean floor
As eruptions continue to occur, the older crust is pushed away
So what does that tell you about where the oldest and youngest layers are?

6. Oceanic Mountains
The mountains in the mid-ocean ridges are formed in two ways
1) they can erupt on the ridge and build up along the ridge
2) as the lava cools and forms new crust, it cracks, forming jagged mountain ranges
Sediment does accumulate on the ocean floor
The farther you go away from the mid-ocean ridge, the seafloor becomes smooth
Forms abyssal plains

7. The rock layers are magnetized
Normal polarity: when magnetized objects point north
Reversed polarity: when magnetized objects reverse direction and point south
Magnetic reversal: this is when the magnetic field reverses direction
This occurs every few hundred thousand – every few million years
A magnetic field is formed by movement of electrons of the molten iron in the outer core

8. Extra resources https://www.youtube.com/watch?v=6CsTTmvX6mc
ading.html
Brainpop “Ocean Floor”

9. Chapter Standards Primary Standards Secondary Standards
SC.7.E.6.2 – Identify the patterns within the rock cycle and relate them to surface events (weathering and erosion) and sub-surface events (plate tectonics and mountain building)
SC.7.E.6.4 – Explain and give examples of how physical evidence supports scientific theories that Earth has evolved over geologic time due to natural processes
SC.7.E.6.5 – Explore the scientific theory of plate tectonics by describing how the movement of crustal plates causes both slow and rapid changes in Earth’s surface, including volcanic eruptions, earthquakes and mountain building
SC.7.E.6.7 – Recognise that heat flow and movement of material within Earth causes earthquakes and volcanic eruptions, and creates mountains and ocean basins.
Secondary Standards
LA the student will organize information related to a topic through charting, mapping, paraphrasing, summarizing, or comparing/contrasting.
MA.6.A.3.6 Construct and analyze tables, graphs, and equations to describe linear functions and other simple relations using both common language and algebraic notation.
Data – See Bi-Weekly Analysis
ESE/504/ELL – Separate Page
Green = On Level
Yellow = Below level
Blue = Above Level

10. Vocabulary – 14 words – Chapter 4
Lesson 1 – p126
Lesson 2 – p134
Lesson 3 – p142
Pangea
Continental Drift
Mid-Ocean Ridge
Seafloor spreading
Normal polarity
Magnetic reversal
Reversed polarity
Plate tectonics
Lithosphere
Divergent, Transformed, and Convergent plate boundaries
Subduction
Convection
Ridge push
Slab Pull