A comprehensive 7th-grade Earth Science lesson exploring tectonic plate boundaries, mantle convection currents, and geologic surface features aligned with Indiana Academic Standards. Students investigate convergent, divergent, and transform boundaries through hands-on modeling, diagram analysis, and evidence-based assessments.
Plates scrape horizontally past one another. Jagged rock edges lock together under friction. Tension builds for decades until they snap.
Crucial Distinction
Crust is neither created nor destroyed. There are no magma plumes or trenches, but shallow, devastating earthquakes occur.
San Andreas Fault
Pacific Plate slides northwest past the North American Plate at ~3.5 cm/year.
Causes California's major tremors
Feature: Visible surface fault lines & offset river beds Slide 5 of 6
Master Summary
Quick Field Review
Boundary
Motion
Crust Effect
Key Landforms
Divergent
Moving Apart (← →)
Created (New Rock)
Mid-Ocean Ridge, Rift Valley
Convergent
Colliding Together (→ ←)
Destroyed or Folded
Trenches, Volcanoes, Mountains
Transform
Sliding Past (↑↓)
Conserved (No change)
Fault Lines, Offset Streams
Exit Question
"Why do volcanic island arcs form near ocean trenches, but never along transform fault lines?"
Hands-on modeling lab up next! Slide 6 of 6
1. Did either cracker sink into the frosting? Describe the shape formed at the collision.
2. Which global mountain range is actively forming this way today?
Post-Lab Synthesis Analysis
1. Indiana Connection: Indiana sits near the center of the North American Plate. Based on today's models, explain why Indiana experiences very few active volcanoes compared to the US West Coast.
2. Conservation of Crust: If new crust is constantly being created at mid-ocean divergent ridges, explain why Earth as a whole is not expanding like an inflating balloon.
The Geological Puzzle: Paleontologists climbing near the peak of Mount Everest (over 8,000 meters above sea level) uncovered limestone rock containing fossilized marine creatures, such as trilobites and ancient sea lilies.
Using your understanding of plate motion, continental collisions, and rock layers, explain how oceanic marine fossils ended up at the highest elevation on Earth.
Scientific Claim (Direct Answer):
Geologic Evidence (What physical facts support your claim?):
Scientific Reasoning (How does plate tectonic theory explain this uplift?):
Part 5: Geohazard Analysis (4 pts)
Explain why the island nation of Japan suffers from catastrophic earthquakes, explosive volcanoes, and tsunamis, while the state of Indiana has no active volcanoes and very rare major earthquakes. Relate your response directly to plate boundaries.
The rock layers forming the Himalayan mountain peaks originated as ancient ocean floor sediments that were pushed thousands of meters upward during a continental-continental collision.
Exemplar Evidence (2 pts):
Trilobites and sea lilies are marine organisms that only live and fossilize in ocean waters. The rock at the summit is limestone, which forms underwater from compressed seashells and marine sediment.
Exemplar Reasoning (2 pts):
Millions of years ago, the Tethys Ocean separated India from Asia. As tectonic convection moved the Indian Plate northward into the Eurasian Plate, the ancient oceanic basin closed. Because both continental landmasses were too buoyant to subduct into the mantle, the seafloor sedimentary rock was crumpled, folded, and uplifted into towering mountain peaks.
Part 5: Geohazard Analysis Model Answer (4 pts)
Model Response: Japan is situated directly on active convergent subduction zones along the Pacific Ring of Fire where multiple tectonic plates collide and plunge into the mantle, melting rock into magma (explosive volcanoes) and causing severe underwater fault slips (earthquakes and tsunamis). In contrast, Indiana is located in the stable interior of the North American Plate, thousands of kilometers away from any active plate boundary or subduction zone.
Performance Banding & Remediation Recommendations
Exceeds (27–30 pts):
Student articulates convection mechanics, differentiates crust density, and applies CER reasoning accurately. Extension: Assign seafloor magnetic striping.
Proficient (21–26 pts):
Mastered boundary motions and standard landforms. Minor gaps in density explanation or reasoning precision. Review crust creation vs. destruction.
Needs Support (<21 pts):
Confusion between transform and divergent motions or subduction vs collision. Provide tactile manipulative cards and re-model with video cross-sections.
