Internal and External Forces – Folding, Faulting, Erosion and Deposition

GeographyEarth's Structure & LandformsAges 15–16

A cross-section of Earth's crust with horizontal rock layers. Choose compression (two plates push together, folding rock into anticlines and synclines) or extension (rock fractures, forming horsts and grabens), then press Run: internal forces lift the terrain at a set rate in mm/year, while external forces — weathering and erosion — wear down the peaks and deposit material into low spots, building plains. Drag on the cross-section to raise or lower a section of crust yourself; the readout shows elapsed time, peak elevation, and the thickness of eroded and deposited material.