Unit 05 · Plate Tectonics & Mountain Building
Earth’s outer shell is broken into slabs that grind past, pull apart from, and dive beneath one another. This unit covers the three boundary types — divergent, convergent, and transform — the seafloor spreading that widens ocean basins and the subduction that consumes them, the engine that drives it all (mantle convection, ridge push, and slab pull), and orogeny: the folding, faulting, and uplift that raise a mountain belt. Mastery means you can read a boundary from its features, predict the landforms and hazards it produces, and trace how a range is built.
| Criterion | Not yet | Approaching | Mastered |
|---|---|---|---|
| Plate boundaries & their features | Cannot tell divergent, convergent, and transform boundaries apart. | Names the three boundary types but misreads which features mark each. | Classifies a boundary from its landforms, earthquakes, and volcanism, distinguishing divergent, convergent, and transform. |
| Seafloor spreading & subduction | Treats the ocean floor as fixed and ageless. | Describes spreading or subduction but not how they balance. | Explains how new crust forms at ridges and old crust returns at trenches, using seafloor age and magnetic stripes as evidence. |
| The driving engine | Says plates move but cannot say why. | Names mantle convection but omits ridge push and slab pull. | Explains plate motion through mantle convection, ridge push, and slab pull, and weighs their relative roles. |
| Orogeny & mountain building | Cannot connect colliding plates to mountains. | Links collision to uplift but not to folding or faulting. | Traces how convergence folds, faults, and uplifts crust into a mountain belt and reads that history from rock structure. |
| Lab technique (plate-boundary & seismic-map modeling) | Cannot locate boundaries on a map. | Plots earthquakes or volcanoes but draws boundaries loosely. | Maps earthquake and volcano patterns to locate plate boundaries and defends each boundary type from the seismic evidence. |
| Integration (cross-domain) | Treats the science as isolated facts; makes no cross-domain connection. | Names a link to history, reading, or writing but cannot defend why it matters. | Connects the unit to its anchor across History · Reading · Writing (plus chosen electives) and defends why the connection matters. |
“This deep band of earthquakes plunging under the trench tells me it’s a convergent boundary with subduction — that’s why there’s a volcanic arc behind it. The slab is being pulled down by slab pull, not shoved by the continent.”
“The plates just move around. This is where two of them meet, and mountains happen because they crash. I’m not sure what makes them move.”
You demonstrate this unit by modeling a plate boundary from a seismic and volcanic map — classifying it, predicting its landforms and hazards, and tracing how it builds or destroys crust aloud, not on a multiple-choice test. A criterion counts as mastered only when your boundary call matches the map evidence and you can justify the driving forces behind it. Mastery is demonstrated, not awarded.
A 5-page clipboard packet — unit overview, key terms, the mastery rubric, anchor examples, and a score sheet you can print and grade against.