8th grade Science Midterm Study Guide – Flashcards
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Sonar
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ocean floor mapping technology (SOund NAvigation and Ranging) which uses sound waves to calculate the distance to an object.
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Sea-Floor Spreading
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the process of mid ocean ridges continually adding new material to the ocean floor; begins at the mid ocean ridge
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Deep Ocean Trenches
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deep underwater canyons ; oceanic crust bends downward
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Mid-Ocean Ridges
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mountain ranges that run along the middle of some ocean floors; mid ocean ridges form long chains of mountains that rise up from the ocean floor
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Conduction
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the transfer of thermal energy from one particle of matter to another
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Subduction
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the process by which oceanic crust sinks beneath a deep-ocean trench and back into the mantle at a convergent plate boundary
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shearing
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stress that pushes masses of rock in opposite directions, in a sideways movement.
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tension
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stress that stretches rock that it becomes thinner in the middle
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compression
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stress that squeezes rock until it folds or breaks
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Normal Fault
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a type of fault where the hanging wall slides downward; caused by tension in the crust
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Reverse Fault
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a type of fault where the hanging wall slides upward; caused by compression in the crust
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Strike-Slip Fault
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a type of fault in which rocks on either side move past each other sideways with little up or down motion
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Pangaea
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the name of the single landmass that began to break apart 200 million years ago and gave rise to today's continents
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Albert Wegener Theories
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Wegener's hypothesis was that all the continents were once joined together in a single landmass and have since drifted apart.
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Fossils
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any trace of an organism that has been preserved in rock
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Plate Tectonics
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theory that states that Earth's plates are in slow, constant motion, driven by convection currents in the mantle.
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Divergent Boundaries
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plates that move apart from each other
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Convergent Boundaries
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plates that come together
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Transform boundary
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plates that slip past one another
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Continental Drift
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idea proposed by Wegner that the continents have slowly moved over the earths surface
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Minerals
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form as hot magma cools inside the crust, or as lava hardens on the surface; when these liquids cool to a solid state they become crystals
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Igneous rocks
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forms from the cooling of magma or lava
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Sedimentary Rock
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forms when small particles of rocks or the remains of plants and animals are pressed and cemented together
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Metamorphic rock
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forms when a rock is changed by heat or pressure, or by chemical reactions; most form deep underground
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Granite
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light colored rock that has high silica (silicon and oxygen) content
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Rock cycle
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forces deep inside Earth and at the surface produce a slow cycle that builds, destroys, and changes the rocks in the crust
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Weathering
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the chemical and physical processes that break down rock and other substances
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Erosion
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the process by which water, ice, wind, or gravity moved weathered particles
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Streak
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the color of a mineral's powder
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Texture
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the look and feel of a rock's surface determined by the size, shape, and pattern of a rock's grains
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Density
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the measurement of how much mass of a substance is contained in a given volume
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Fracturet
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the way a mineral looks when it breaks apart in an irregular way
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Deposition
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process in which sediment is laid down in new locations
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Coarse Grains
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rocks with grains that are large and easy to see
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Fine grain
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rocks that have grains that are so small they can be seen only with a microscope
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Mohs hardness scale
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used to rank the hardness of minerals from 1-10
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crystallization
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the process by which atoms are arranged to form a material with a crystal structure.
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Inorganic Processes
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every mineral must be able to form from materials that were not part of living things
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Properties of Minerals
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Color, Streak, Luster
