How landforms are created and shaped — plate tectonics, weathering, and the rock cycle.
The Earth's lithosphere is broken into several rigid tectonic plates that float on the semi-molten asthenosphere below. Their movement — at boundaries that are convergent (colliding, forming mountains or trenches), divergent (moving apart, forming mid-ocean ridges or rift valleys), or transform (sliding past each other, causing earthquakes) — explains most of Earth's large-scale landform features, including the formation of the Himalayas from the collision of the Indian and Eurasian plates.
Rocks are classified into three types, and constantly cycle between them over geological time: Igneous rocks (formed from cooled magma/lava), Sedimentary rocks (formed from compressed and cemented sediment), and Metamorphic rocks (formed when existing rocks are transformed by heat and pressure).
Landforms are also shaped by weathering (the breakdown of rocks in place, either physically, chemically, or biologically) and erosion (the transport of weathered material by agents like rivers, wind, glaciers, and waves), which together sculpt features like valleys, canyons, and coastal cliffs over time.
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