Navo middle school science Unit 7 Vocabulary Navo middle school science

Crust Brittle, rocky outer layer of Earth Least dense layer Oceanic crust is more dense and thinner than continental crust

Mantle Layer directly below the crust Is the thick middle layer Contains lithosphere and asthenosphere Less dense than the core, more dense than the crust

Lithosphere The crust and the uppermost mantle Rocky layer that is brittle and rigid

Asthenosphere Located directly below the lithosphere The partially melted, plastic-like layer within the mantle The asthenosphere flows very slowly

Outer core Part of the dense metallic center of Earth Is a very hot liquid layer of Earth Moves independently from the inner core Causes magnetic field of Earth

Inner core Part of the dense metallic center of Earth Is a solid ball of iron crystals Is under so much pressure that it stays a solid Spins a little bit faster than the rest of earth Causes Earth’s magnetic field

Rock Natural, solid mixture of minerals or grains Scientists can classify rocks based on the way the are formed, their grains, texture, composition, and color

Igneous rocks Rock that is formed when molten rock (magma) reaches Earth’s surface (lava) and cools When magma cools, it crystallizes, thus creating Igneous Rocks Igneous rocks form in a variety of environments: Subduction zones Mid-oceanic ridges Areas of volcanic activity

Sedimentary rocks Forms where sediment is deposited Sediment: rock material that forms where rocks are broken down into smaller pieces or dissolved in water as rocks erode They are commonly formed at: Rivers and streams Deserts and valleys Mountain valleys

Metamorphic rocks Formed when rocks are exposed to extreme temperature and pressure, such as along plate boundaries, where rocks can change to metamorphic rocks metaMORPHic rocks CHANGE Can form from igneous rocks, sedimentary rocks, or other metamorphic rocks

Rock Cycle The series of processes that change one type of rock into another type of rock The rock cycle NEVER STOPS

Plate tectonics Theory that states that Earth’s surface is made up of rigid slabs of rock, or plates, that move with respect to each other Alfred Wegener Provides an explanation for earthquakes, volcanoes, mountains, etc.

Earth’s Tectonic Plates

Divergent plate boundaries Forms when two plates separate Mid-ocean ridges are located along divergent boundaries SEAFLOOR SPREADING occurs, causing new crust to form Can also exist in the middle of a continent, causing RIFT VALLEYS to form

Transform Plate boundaries Forms where two plates slide past each other San Andreas Fault in California As plates slide, they can get stuck and stop moving, causing force and stress to build up, until finally the plates move, causing an EARTHQUAKE

Convergent plate boundaries Form when two plates collide, the denser plate sinks below the other plate in a process called SUBDUCTION When oceanic plates collide with continental plates, the denser oceanic plate subducts under the edge of the continent, creating a DEEP OCEAN TRENCH and a line of VOLCANOES When 2 oceanic plates collide, the older and denser oceanic plate subducts beneath the younger plate, causing a DEEP OCEAN TRENCH and a line of VOLCANOES When two continental plates collide, neither plate is subducted, and mountains form from uplifted rock

Convergent plate boundaries