Planet Earth

Earth’s Formation The earth formed by accretion of dust and small objects in the early solar system. Heat from collisions Melt and reform Earth rocks are compared to meteorites and moon rocks. orbital motion collision different orbit

Layers in the Earth Heating the earth caused the heavy metals to sink and lighter minerals to rise. inner core outer core mantle crust

Seismic Waves Earthquakes near the surface create vibrations. P waves compress S waves shake, slower Waves can be measured at surface points far away. Interior information

Core The earth’s core consists of iron and other metals. 3500 km radius Radioactivity keeps it hot. Temperature to 6500 K Liquid metal outer core Density keeps part solid. Solid within 1200 km Pressure over 1 million atmospheres U Colorado

Mantle Lighter minerals congregated above the core. Silicates: silicon, aluminum, magnesium, oxygen Iron, too The mantle is solid, but plastic. Slow movement, like putty under pressure. crust mantle convection outer core

Crust The crust is the cool, hard surface of the mantle. ocean - more dense, basalt rock continents - less dense, granite rock The crust is very thin; 10 km out of 6400 km radius. continent ocean floor crust mantle outer core

Plate Tectonics Motion in the mantle causes the crust to split. Earthquakes, mountains, volcanoes Plate tectonics causes continents to move over millions of years. overriding plate crust mantle descending plate outer core ZME Science

Hot Plumes The heat from the outer core causes molten rock to rise through the mantle. Surface rises The dense rock causes gravity to be very slightly higher. bulge at the surface crust mantle plume outer core

Volcanism Plumes that push material to the surface form volcanoes. Gases and minerals in volcanoes tell us about the earth’s mantle. volcano crust mantle plume outer core