Changes within our planet affect the natural world. Grade 3 PYP How the world works. 24 Vocabulary words each with a picture, definition, and an example sentence. Vocabulary words include: geology, tectonic plates, magma, erosion, movement, transform, pressure, cause, impact, crust, mantle, core, mining, quarry, trench, convergent, divergent, subduction, igneous, sedimentary, metamorphic, affect, effect, explain.