science Ch.4 2
Terms
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- What is the thin and solid outermost layer of the earth above the mantle?
- crust
- What is the layer of rock between the Earths's crust and core, contains most of Earths' mass?
- mantle
- What is the central part of the Earth?
- core
- What is a substance composed of 2 or more elements (chemically combined)
- compound
- Why do less dense compoud make up the Earth's crust while the densest compounds make up the core?
- because of the pull of gravity
- What are the five main physical layers of the Earth?
-
-lithosphere
-asthenoshpere
-mesosphere
-outer core
-inner core - What is the outermost, rigid layer of the Earth?
- lithosphere
- What is the 2nd layer that's solid rock that can flow, plates move on it, and is malleable?
- asthenosphere
- What is the strong, lowest part of the mantle?
- mesosphere
- What is the liquid layer of the core?
- outer core
- What is the solid, dense center? (solid because of preasure)
- inner core
- What is the block of lithosphere that consists of the crust and rigid most outer layer of the mantle and moves around top of asthenosphere?
- tectonic plate
- What types of tectonic plates are there?
- continental, oceanic, and a combo of both
- What are some ways scientists know about the structure fo the Earths' interior?
-
-measure the speed of seismic waves
-travel times of seismographs - Who was Alfred Wegner?
-
scientist who proposed the hypothesis of the continental drift
(early 1900s) - What is the Continental Drift Hypothesis?
- hypothesis that states continents once formed a single landmass, broke up, and driftedd to their present location
- What evidence supports the Continental Drift Hypothesis?
-
-fossils of same organisms found of both sides of ocean
-similar rocks found on differnt continents
-coastlines roughly matche up
-mt. ranges would line up if land was back together - What was a single landmass when continents were joined?
- Pangaea
-
-magma rises to surface and solidifies, fills gap between moving tectonic plates
-new crust forms - Sea Floor Spreading
- What evidence supports the sea floor spreading hypothesis?
- oldest crust farthest away from ridge
- List 2 things that the reversed magnetism of the ocean floor tells us about the earth's history.
-
-all ocean floor was not formed at once
-earth's magnetic poles have reversed in the past - What is an underwater mountain chain that runs through Earth's ocean basins?
- mid-ocean ridge
- What occurs in the rift valley at the mid ocean ridge?
- magma rises, lava hardens into new ocean floor
- What is the theory that explains how large pieces of the Earth's outermost layer move and change shape on the asthenosphere?
- plate tectonics
- What are the 3 types of boundaries?
-
-convergent
-divergent
-transform - What boundary is it when plates collide?
- convergent
- What boundary is it when plates seperate?
- divergent
- What boundary is it when plates slide past each other?
- transform
- What is believed to cause the motion of the tectonic plates?
-
-ridge push
-slab pull
-convection - What is it when higher ridge pushes lower oceanic lithosphere down?
- ridge push
- What is it when sinking plate edge is pulled by gravity and pulls on the rest of the plate?
- slab pull
- Explain how scientists use GPS to measure the rate of tectonic plate movement.
- radio signals are continuously beamed from satellites to GPS ground stations
- What is it when oceanic crust collides with continental crust, and the denser oceanic crust sinks into the asthenosphere?
- subduction
-
What is it when the shape of rock changes cuz of stress?
(rock layers can bend and brake) - deformation
- What is stress that occurs when an object is squeezed?
- compression
- What is stress that occurs when forces stretch an object?
- tension
- What happens when folding occurs with rock layers?
- rock layers bend cuz of stress
- What is the surface along wich rocks break and slide past each other?
- fault
- What are the 3 types of faults?
-
-normal
-reverse
-strike slip - What fault occurs when plates are pulled apart?
- normal
- What fault occurs cuz of compression?
- reverse
- What fault occurs when opposing forces break rock and move horizontally?
- strike slip
- What forms from collisions at convergent boundaries, can form highest mts. in world, and is the most common?
- folded mountains
- What forms when tension at normal fault cause large blocks of crust to drop down relative to others? (sharp, jagged rocks)
- fault block mountains
- What usually forms at a convergent boundary where suduction occurs?
- volcanic mountains