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8-Sci - Unit3 L2-3
8-Sci-Unit3-Lessons2-3 Plate Tectonics
Term | Definition |
---|---|
continental drift | the hypothesis that today's continents were once part of a single landmass. |
plate tectonics | theory that states Earth's surface is made up of giant moving slabs called tectonic plates. |
theory | explains HOW something happens in the natural world. |
law | explains WHAT happens in the natural world. |
sea-floor spreading | the process by which new sea floor is formed |
subduction | the process by which one tectonic plate is pulled beneath another plate |
magnetic reversal | a change of the magnetic poles on Earth |
convection current | any movement of matter that results in a difference of density |
lithosphere | outermost physical layer of Earth, a ridged solid layer made of rock |
asthenosphere | layer immediately below the lithosphere, solid layer of made of rock that is weak and flows slowly. |
tectonic plates | large moving pieces of lithosphere |
compression | a stress that squeezes or shortens material |
tension | a stress that lengthens or pulls a material apart |
shear | stress that causes material to twist or become distorted |
convergent boundary | boundary that is formed when tectonic plates move toward each other and collide |
divergent boundary | boundary that is formed when tectonic plates move away from each other |
transform boundary | boundary that is formed when tectonic plates move past one another in opposite directions |