Rose Wright, Elizabeth Robinson, Cody Stoelzle, Don Harris corethe very center of Earth; two parts: inner core, which is made of solid metals due to the pressure on it, and the outer core made of liquid metal. mantela thick layer of hot, dense rock which is partially melted. crusta rocky shell forming the earths surface continental drift: theory that the continents were once joined and then drifted apart. Thus it is also believed that the plates float freely upon the mantel. plate tectonics: all of the physical processes that create Earths physical features. magma: molten rock from the mantel. subductionprocess by which two plates collide and the lighter of the two sinks beneath the other. This process can also cause mountains, because the lighter one pushes the other upwards. accretionthe pieces of Earths crust come together slowly as the sea plates slide under continental plates. This is the opposite of spreading, which causes trenches. Himalayas: a mountain range south of Asia being the tallest in the world foldsbends in the layers of rock, similar to subduction but involving layers of the same mass. faultscracks in the earths crust faultingwhen land is folded and reaches a breaking point. The land then shatters and the shards then grind against each other creating small earthquakes. San Andreas Faultline; one of the most famous fault lines in the world, caused by faulting. The scar you see here is from the last time a faulting happened in this area. Kobeplace in Japan where disasterous earthquakes have happened. San Franciscocity in California; site of many earthquakes. Most famous being a massive fault shift that tore the city apart. Ring of Fireone of the most earthquake- and volcanic-prone areas on the globe. One of the biggest and fastest-acting forces to change Earths features. Weathering: a force that breaks down rocks Erosion: wears away Earths surface by wind, glaciers, and moving water Movement of dust, sand and soil. Its a constant force of change responsible for some of the most obscure geographical features. morainesrock and debris left over when glaciers melt. Greenlanda northern, Scandinavian country almost completely covered in ice. Antarcticacontinent much like Greenland, covered in glacial sheets that are increasingly receding. glacierslarge bodies of ice that move across Earths surface Water erosion begins when spring- and rain-water flow down in streams that cut through land. This force is responsible for the Grand Canyon Grand Canyon: product of water erosion