Dorchester School District Two



Earth Science– Midterm Review 2019UNIT 1: INTRODUCTION TO EARTH SCIENCEBranches of Earth Science: Astronomy – study of the universeGeology – study of Earth’s rocks & mineralsMeteorology – study of atmosphere as it pertains to weather & climateOceanography – study of the ocean environmentTopography: the size & shape of the land surface features of a regionElevation – height above sea levelProfile – cross-sectional (side view) graph of the land’s elevationContour line – a line that connects points of equal elevation on a mapContour interval – difference in elevation between each contour line on a mapGradient – change in elevation; the closer the contour lines, the steeper the gradientPrecise v AccuratePrecise – the closeness of two or more measurements to each otherAccurate – closeness of a measured value to a standard or known valueUnit 2: The universeElectromagnetic radiation = energy traveling through space in the form of wavesElectromagnetic spectrum = radio waves (longest wavelength, lowest frequency), microwaves, IR waves, visible light (ROYGBIV), UV waves, X-rays, gamma rays (shortest wavelength, highest frequency)Red light has longer wavelength & lower frequency than Blue light.Telescopes – uses lenses and mirrors to view objects too far to see with naked eyeAccording to Hubble Law – the universe is expanding as we have a shift toward red end of the spectrum (red-shift)Big Bang Theory – billions of yrs ago, all matter & energy was compressed to a small volume; a sudden event sent all thematter & energy outward and is still expanding today. Evidence to support Big Bang = cosmic background radiation, red shift of galaxies & dark energySteady State Theory – states that the universe is expanding due to the formation of new matter & suggests that the observable universe remains unchanged.Gravity/Gravitational force caused the formation of the galaxies.3 types of GalaxiesIrregularSpiralEllipticalAge & composition (what does the galaxy contain?)Young – mostly young, some old stars. New stars are being made. (Contains gas).Midlife – young & old stars. Gas & dust can make new stars.Old – mostly old stars. NO gas/dust for new star formation. Shape (appearance) & defining featuresNo patterned or uniform shape – may look explosive. Has a disk. Central galactic bulge, flattened disk (w/ spiral arms), halo of faint/old stars No galactic disk. 3D shape almost flattened to nearly spherical. Bright central nucleus. Orbits? Describe.Gas and stars in the disk move in irregular orbits Gas and stars in disk move in circular orbit around the center. Stars move in random orbits. Earth’s galaxy, group & supercluster = Milky Way Local Group Virgo superclusterParts of an Atom = Proton (positive charge), Neutron (no charge/nuetral) & Electron (negative charge)Nucleus = protons + neutronsElements are defined by their number of protons = atomic numberNuclear fusion = two small nuclei fuse to form one larger nucleus resulting in energy given off; occurs in stars & the SunStellar evolution = life cycle of a star = nebula, protostar, main-sequence star, giant or supergiant, planetary nebular or supernova & white dwarf or neutron star or black holeThe mass of a star determines its progression in its life cycle; 90% of a star is spent as a main-sequence star; more mass of a star, the more quickly it burns.noHertzsprung-Russell diagram classifies stars by temperature & luminosityHR Diagram: y-axis is luminosity (low to high going up) while x-axis is temperature in Kelvin going from high to low as you move left to rightUNIT 3: The Solar SystemSun: core, reactive zone & convection zone; photosphere= innermost layer, chromosphere, corona= outermost layer; sun spots= area of photosphere, strong magnetic field; solar flares= explosive release of energy associated with magnetic disturbances on surface; solar winds= made up of plasma escaping the sun’s gravity Inner Plants=terrestrial planets; mostly solid rock & metallic cores; surfaces have impact cratersMercury: 1 orbit around sun=88days; heavily cratered, no atmosphereVenus: 1 orbit=225days; rotation=243 days; Earth’s twin as most similar in size, mass & densityEarth: formation ~4.6billion years agoCrust=outermost layer; thinnest & least dense of the layers; continental crust= more iron, calcium & magnesium than oceanic; oceanic crust=thinner & more dense than continental crustMantle=layer btwn crust & core; thicker & more dense than crust; makes up 67% of earth’s crustCore=central part of earth; most dense of the 3 layers; made up of mostly iron & nickel5 physical layersLithosphere=outermost rigid layer making up crust & upper part of mantle; divided into tectonic platesAsthenosphere=plastic layer of mantle on which tectonic plates move; solid rock that flows slowlyMesosphere=strong layer btwn astheno & outer coreOuter core=liquid layer of the core below the mantleInner core=solid, dense center; about 680 km beneath the surface3 types of tectonic plate boundariesConvergent boundaries=results from 2 plates collidingDivergent boundaries=2 plates separating forming new sea floorTransform boundaries=2 plates sliding past each other horizontally (ex: San Andreas Fault)Plate motion may be result of changes in the density within the asthenosphereAtmospheric changes: early earth had high concentration of hydrogen and helium; volcanic activity release large amount of gases (water vapor, CO2, N2, methane, SO2, & ammonia); oxygen close to earth resulted from blue-green algae that used the CO2 for photosynthesis; present atmosphere=78% N2, 21% O2, 1% other gasesMovements of the EarthRotation=spinning on its axis; 1 rotation=1 day; evidence=constellations appear to be moving in an arcOrbit= path a body travels around another bodyRevolution= earth moving around the sun; 1 revolution=1year; ellipse, not a circle; farthest from sun in July, closest in January; evidence=different constellations visible from month to monthCoriolis Effect= curving of the path of a moving object from a straight path; acts in a North-South direction; at equator=0Seasons: caused by the tilt of the Earth on its axis of 23.5 degrees (not by distance from sun!); summer=north pole toward sun is greatest so longer days; winter solstice=north pole tilted farthest from sun, fewest daylight hoursEarth’s moon: aka Luna, more than 1/4th the size of earth; gravity is 1/6th of that of earth; surface=craters, mountain ranges, riles & lava plains; no magnetic field, atmosphere; takes 27.322 days to rotate around the earth; 5th largest moon in solar systemMars: orbit=687days; rotation=24hrs37min; axis similar to Earth’s so has seasons similar; active volcanoes; pressure & temp too low for water to exist as liquid on surface; water present in past; 2 irregularly shaped moons (Phobos & Deimos) Outer Planets=gas giants; separated from inner planets by asteroid beltJupiter: largest; giant red spot=rotating storm; enormous magnetic field; 4 large Galilean moons: Io (innermost with volcanoes), Europa (crust of ice), Ganymede (largest of moons, own magnetic field) and Callisto (farthest, most densely cratered moon)Saturn: very cold; at least 60 moons; least dense planet; bulge @equator, flat @poles; moon Titan is largest, most are icy bodies with cratersUranus: 3rd largest; methane in atmosphere gives blue colorNeptune: similar to Uranus; at least 13 moons, 6 rings; active weather system; moon Triton has a retrograde orbitComets: small bodies of ice, rock & cosmic dust; most famous is Halley’s Comet (every 76yrs); core, coma & 2 tailsAsteroids: fragments of rock; Ceres is largest; also considered dwarf planetMeteoroids: small rock or metal bodies detached from comet; larger ones result of collisions btwn asteroidsMeteors: shooting starsMeteorites: remnant of meteoroid that did not totally burnDwarf Planets: any object that orbits the sun, is round in shape due to its own gravity, not a satellite of another planet; ex: PlutoKuiper Belt: thousands of small objects beyond Neptune’s orbit, including dwarf planets Pluto & ErisAstronomyCopernicus – heliocentric model of the solar system, meaning sun-centeredGalileo – discovered evidence to support heliocentric model, observed 4 moons of Jupiter & rings of SaturnNewton – formulated the Universal Law of GravitationKepler – developed 3 laws of planetary motionLaw of ellipses – each planet orbits sun in ellipseLaw of equal areas – equal areas covered in equal amounts of time as orbiting sunLaw of periods – planets orbital period depends upon its distance from sunUnit 4: Earth-Moon SystemUnique properties of the Moon: no atmosphere; gravity is 1/6th of Earth’s ; mass is 1/8th of Earth’s; diameter is ~1/4 of Earth’s; temp is -170oC to 134oCFeatures of the Moon: cratersrays (light streaks extending outward from young craters)mare/maria (dark areas of cooled basaltic lava)highlands (lighter areas of anorthosite rock)riles (long deep channels running thru maria)ridges (long narrow elevations across maria)regolith (layer of dust and moon rock)Phases of the Moon:Solar Eclipse=sun/moon/Earth aligned w/moon in middle Lunar Eclipse=sun/Earth/moon aligned w/Earth in middle Tides: caused by moon’s gravitational pull on Earth & its oceans; spring tide=earth, sun & moon aligned, stronger pull, greater tidal range; Neap tide=moon & sun at right angles to each other relative to Earth, gravitational forces work against each other so smaller tidal rangeCharacteristics of EarthShape=oblate spheroid meaning slightly flattened at the polesCrust=oceanic & continental; oceanic is thin, more dense, below water level compared to continental; oceanic made up of basalt rock while continental is made up of graniteMantle=thickest layer of Earth; separated from crust by Moho boundary; density increases with depth due to increasing pressure; makes up 2/3rd of Earth’s mass; lithosphere=upper mantle+crust, broken into plates; asthenosphere= flowing solid layer below lithosphere; mesosphere=solid mantle rock layer below asthenosphereCore=innermost layer=center of the Earth; heaviest, most dense layer of iron & nickel; outer core is slow flowing liquid responsible for Earth’s magnetic field; inner core=spinning solidSeismic waves provide evidence of solid inner coreEarth’s heat comes from: radioactive decay, gravitational contraction & tidal forces which occur internally, while the sun heats externallyUnit 5: Rock CycleMinerals=naturally occurring, inorganic solid, with definite chemical composition & a crystalline structure; makes up rocks; used in everything!Color – depends upon its compositionStreak – color in powdered form; may be different than when a solidLuster – how reflects lightCrystal Structure – crystalline shapeHardness – how hard the mineral is; MOHS scale (10 being hardest=diamond, 1 being softest=talc)Fracture & Cleavage – how a mineral breaksDensity = mass divided by volumeRock Cycle=rocks can go thru several processes to change from igneous to sedimentary to metamorphicIgneous Rock=forms from cooling magma & lavaMagma=intrusive (inside earth), cools slowly, forms large crystals or coarse grainsLava=extrusive (outside the earth), cools rapidly, forms small/fine grains, no crystalsClassified as intrusive/extrusive and by mineral contentFelsic Rock=high silica content, light in colorMafic Rock=low silica content, darker in colorSedimentary Rock=breaking down of larger rocks into smaller by physical or chemical meansPhysical=weathering, erosion, compaction & cementation (abrasion, freeze-thaw, animals, plants); increased surface area means more rock to be exposed to physical changesChemical=oxidation, acid precipitationDepositional environment=where the sediment (smaller rocks) are deposited such as river beds, beaches... where the sediment ends up depends upon how the sediment is moved whether by wind, water or ice; the further the sediment travels, the smaller the particle size as the rock becomes smaller from abrasion and sorted by sizeClassified by chemical composition (may contain dissolved minerals), organic composition (containing shells), or clastic (rock fragments cemented together)Metamorphic Rock=formed by recrystallizationRegional=occurs over large area such as mountainsContact=rock comes in contact with igneous rockClassified by mineral content and if course or fine grained **Foliated=2+minerals & banded patternOR**Nonfoliated=contains one mineralSoil – parent rock breaks down, combined with organic matter, humus, water & air; characteristics depend on the parent rockClay soils are rich in aluminumSandy soils are rich in quartzBlack soils contain more organicsRed soils contain more redsSoil Profile=sampling of the soil for a certain region; take a sample that goes down at least 3 feet to get a true sampling of what the profile is below the surface layer.Unit 6: Plate TectonicsContinental Drift=a HYPOTHESIS that Alfred Wegener developed as he noticed that the separate continents had matching fossil records, matching rock formations & mountain ranges, and climate evidence so he hypothesized that there was once a supercontinent called Pangaea that over millions of years broke apart and the land masses called plates moved to their current location; Wegener could not explain how they moved that is why it is only a hypothesis!Plate Tectonics = a THEORY based on mid-ocean ridges forming new crust & sea-floor spreading as theorized by Harry HessMid-ocean ridges=formation of new crust; sediments closest to the ridge is thinner & increases in thickness further from the ridge, suggesting the thinner layer is newer and the thicker is older as the sediment collected over timeSea-floor spreading=as the seafloor spreads apart, new magma comes in to create new rock; a center valley is a rift where the magma filled in the space as the floor spreadPaleomagnetism=the study of rock parallel to the ocean ridges; as the floor spread, the earth’s magnetism changed direction, this change of direction (or reversal) of magnetism in rocks help age the sea floor & supports the theory of sea-floor spreadingHot Spots=areas in the middle of plates where volcanoes form and can help determine rate and direction of moving platesPlate Tectonics Theory= the lithosphere is made up of many ‘solid plates’ that ride on top of the fluid asthenosphere; the asthenosphere layer experience convection of liquid matter as the temperature & pressure increases as you move downward thru the asthenosphere and as the rock becomes heated it becomes less dense & rises thru the asthenosphere, as the hot rock rise it begins to cool and becomes more dense and sinks into the hotter layers of the asthenosphere, a cycling effect of rising and falling rock causes the lithosphere plates to move & interact at their boundariesFault=plane of weakness upon which rocks moveHanging wall=rock above fault planeFootwall=rock below the fault planeNormal Fault=footwall moves up, hanging wall moves down “FUN”Reverse Fault=footwall moves down, hanging wall moves up “FDR”Strike-Slip Fault=grind past each otherDeformation=changes to Earth’s crust in response to stressCompression=squeezing together, compressing the crust plates toward one anotherTension=the pulling apart of crust platesShear=side-to-side motion between platesBoundary=where 2+ plates meetConvergent Boundary=plates come together; compressional stress; reverse faultContinent-Continent=folded mountainsOcean-Ocean=deep sea trenches & volcanic island arcOcean-Continental=Island arcDivergent Boundary=plates move apart; most are located on sea floor; tensional stress; normal faultContinent-Continent= rift valleysOcean-Ocean=mid-island ridgeTransform Boundary=plates move past one another; shear stress; strike-slip faultPlate MovementMantle convection=movement of mantle material due to heating and cooling, heating becomes less dense so rises, cooling becomes more dense and sinks; remember as you move toward core temperature rises, move toward surface & temperature decreasesRidge push=new crust pushes older crust away from the ridge; happens at divergent boundariesSlab pull=plate sinks pulling the rest of the plate with it; happens at convergent boundariesUnit 7: HazardsEarthquake=a sudden release of energy along a fault line; elastic rebound is the sudden return of rock to its undeformed shapeFault=break or crack in land plateFocus=point under the surface where the quake originatedEpicenter=point on the surface of the earth above the focusSeismic waves=waves that radiate outward from the focus at 360 degreesP-Waves=body wave that push-pull particles in the direction of wave movement; travel thru solids, liquids & gases; travel the fastest; first to arrive at a seismographic center; aka compressional waves;S-waves=body wave that shake particles perpendicular to the direction of wave movement; only travel solids; slowest of the body waves; aka shear wavesLove & Rayleigh Waves=surface wavesSeismology=the study of earth movements, such as earthquakes, & seismic waves that move thru & around the earthSeismograph=machine that records the shaking from an earthquakeSeismogram=graph representation used to evaluate earthquake; product from seismographTriangulation=method of locating the epicenter of an earthquake by analyzing the P & S-waves from three different seismic centers; P-waves arrive first, followed by S-waves; plot the distances from the seismic station using circles, where circles connect is where the epicenter is locatedVolcanoes – land masses where magma reaches the earth’s surfaceMagma=hot fluid below the earth’s surface; depends on melting points of minerals present (temperature), pressure on the minerals present (decrease pressure decreases melting point), and fluids present (increasing water decreases the melting point of minerals present); low silica/gas/viscosity/water=faster flowing magma & oozing eruptions; high silica/gas/viscosity/water results in slow flowing magma with more explosive eruptions; cools slowly, forms large crystals or coarse grains; intrusive (inside earth)Lava=magma that has reached the earth’s surface; cools rapidly, forms small/fine grains, no crystals; extrusive (outside the earth)Shield Volcano=largest volcanoes; quiet eruptions; mafic lava; occurs at divergent boundaries or hot spotsCinder Cones=smallest volcanoes; steep slopes; small, explosive eruptions; occurs at convergent or divergent boundariesComposite Volcano=stratovolcano; alternating layers of lava & pyroclastics; lava from quieter eruptions, pyroclastics from explosive eruptions; occurs at convergent boundariesCaldera=crater remaining when volcanic cone collapsesHazards from Volcanoes: lava flows, mudflows (aka lahars), emission of gases, pyroclastic flow &/or trigger earthquakesMagma & Lava are classified by mineral contentFelsic Rock=high silica content, light in color; contains Feldspar and SilicaMafic Rock=low silica content, darker in color; contains Magnesium and Iron ................
................

In order to avoid copyright disputes, this page is only a partial summary.

Google Online Preview   Download