A place for my students to get some help in Earth Science
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| Earth Science A place for my students to get some help in Earth Science |
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Thursday, April 12, 2007 Earthquake Info Seismic Station P-Wave Travel Time A 8 min 20 sec B 0 min 31 sec C 12 min 18 sec D 3 min 20 sec 1. Which station is closest to the epicenter? 2. If the P-wave arrived at station D at 09:25:10, what was the origin time of the earthquake, at the epicenter? 3. How far from the epic center were station A and D? Subject: Earth Science TEST REVIEW Evidence of crustal motion originally strata (layers) are laid down horizontally – but the layers are often found to be tilted, folded or faulted benchmarks indicate changes in elevation i. uplift – rising of crust ii. subsidence – sinking of crust fossils of shallow water organisms found on mountains or at great ocean Depth earthquake Earthquakes produce seismic waves Mercalli Scale – relative scale, based on observations, measures intensity from I – XII Richter Scale – uses seismograph to determine magnitude (total energy) released by earthquake; each increases in number represents a tenfold increase in energy released Focus – place underground where break or fault occurs Epicenter – location on Earth’s surface, just above the focus where earthquake is felt most strongly primary (P) waves – compressional waves, pushing and pulling, travel faster than S waves can travel through both solids and fluids Secondary (S) waves – shear wave, side to side, cannot travel through liquid ESRT – difference in arrival time between P and S waves, mark interval on paper, slide paper over curves until marks meet the P and S cures, follow edge of paper down to horizontal axis to find distance to epicenter (distance recording station is from epicenter) distance x 103 or 1000 Origin Time – Arrival Time – Travel Time = Origin Time To find epicenter – fallow above procedure for 3 seismic recording stations – draw circles – where 3 circles intersect determines the location of the epicenter Layers of the Earth: (properties inferred from behavior of seismic waves) Crust – outermost layer; continental crust is granite like rocks, thicker, oceanic crust is basalt like rocks – dense dark mafic Mantle – includes most of the Earth’s volume Moho – interface (boundary) between crust and mantle Lithosphere – crust and upper ridge part of the mantle Asthenosphere – plastic like part of the mantle Core – mixture of iron and nickel i. outer core – liquid (S waves cannot pass through; P waves slow down) ii. inner core – solid Part of Earth opposite side where earthquake occurs receives P waves but no S waves Surrounding the P wave only zone is a region where neither P nor S waves received (due to refraction/bending at the mantle-core boundary) – this is due to density differences – Shadow Zone Theory of Continental Drift – Earth’s continents have separated and collided as they have moved over Earth’s surface for million of years (ancient continent Pangea – see ESRT page 9) Mid-Oceanic Ridges – encircle Earth oceanic crust is created here – sea/ocean floor spreading – upwelling material from deep in the Earth comes to the surface at the ridges where it spreads apart to make new oceanic crust; youngest crust is near the ridges; oldest crust near the trenches; normal/reversed magnetic polarity is observed in rock records Plate Tectonics – Earth’s surface is composed of approximately a dozen major, rigid Moving crustal plates and some smaller plates - plates move because they are Driven by convection currents in mantle (currents are due to differences in density) ESRT page 5 Types of plate boundaries: Convergent boundary – plates move towards each other and collide – subduction, dense basaltic oceanic plate dives beneath less dense granite continental plate – forms trenches, if 2 continental plates collide you get mountain building (folding, faulting) as with Andes or Himalayas Transform boundary – plates slide past one another produces many earthquakes; example San Andreas Fault in California Divergent boundary or Rift – where plates moving apart as at mid-oceanic ridges Convection cells bring material to the surface at ocean ridges and pull it back into Earth at the trenches Subduction Zone – area where crust is being pulled down into the mantle Zones (belts) of crustal activity – mountain building, volcanoes, and earthquakes are related events ( occur due to internal pressure within the earth) Ring of Fire – surrounds Pacific Ocean Hot Spots – hot plumes of magma pierce the crust as plates move over – results in a chain of volcanoes of different ages (example Hawaiian Island) Labels: Earthquake Info posted by James | 10:18 AMTuesday, April 10, 2007 Final Stuff and Review2007 WEBPAGES FOR THE REGENTS http://jgsearthscience.blogspot.com/ http://www.regentsprep.org/ http://www.nysedregents.org/testing/hsregents.html http://www.regentsearthscience.com/150ways.html http://edusolution.com/regentsexams/regentsindexpage.htm http://www.regentsreviewlive.net/ UNIT SEQUENCE (and suggested time frame) UNIT 1 THE EARTH IN SPACE (3 weeks / 15 lessons) pages 1 through 10 UNIT 2 THE SOLAR SYSTEM & THE COSMOS (3 weeks / 15 lessons) pages 11 through 17 UNIT 3 METEOROLOGY (5 weeks / 25 lessons) pages 18 through 28 UNIT 4 EARTH=S CLIMATE (4 weeks / 20 lessons) pages 29 through 36 UNIT 5 EARTH=S HISTORY (3 weeks / 15 lessons) pages 37 through 45 UNIT 6 MINERALS & ROCKS (3 weeks / 15 lessons) pages 46 through 54 UNIT 7 SURFACE PROCESSES & LANDSCAPES (4 weeks / 20 lessons) pages 55 through 65 UNIT 8 THE DYNAMIC CRUST (4 weeks / 20 lessons) pages 67 through 76 Final Review Sheet Final Review Igneous rock form when magma or lava cools and solidifies Intrusive Rocks slow cooling – when high temperature and pressure produces large crystals (coarse texture) Extrusive Rocks rapid cooling – when rapid drop in temperature and pressure produces small crystals (fine or glassy texture) Example: obsidian (glassy) basalt, pumice Vesicular formed when bubbles of gas vesicles are trapped in solidifying lava example: scoria, vesicular basalt, pumice BY LOOKING AT THE SIZE OF CRYSTALS IN IGNEOUS ROCK, THE RATE OF COOLING OF THE ROCK CAN BE DETERMINED · LARGE CRYSTAL = SLOW COOLING · SMALL CRYSTAL = FAST COOLING Felsic (Al – aluminum) rich in feldspar and silica light in color are most common in the continents granite, rhyolite less dense Mafic (Mg – magnesium, Fe – iron) contain amphibole and pyroxene dark in color are most common in the ocean basin basalt, gabbro more dense Metamorphic Rocks Metamorphic (meta – change; morph – form) are formed directly from existing rock (sedimentary or igneous) heat pressure and chemicals are pushed up to the surface by crustal movements during mountain formation (orogeny) weathering and erosion eventually exposes the metamorphic rocks are formed by the process metamorphism Metamorphism is the recrystalization of unmelted minerals under high temperature and pressure Regional Metamorphism occurs on very large scale and is usually associated with mountain building process (orogeny) Contact Metamorphism occurs when molten lava or magma comes into contact with surrounding rocks and changes them Map symbol – Hairy line Foliation – crystals of minerals become needle like and thy have grown in the same direction (mineral alignment) Banded – light and dark bands Occurs when minerals of different densities recrystalize under pressure and separate into layers More intense temperature and pressure the thicker the mineral bands To calculate your distance from an earthquake epicenter, proceed as follows: Subtract the arrival time of the P-waves from arrival time of the S- waves (this can be ex- pressed in minutes and seconds, such as 06:40). starting at zero on the vertical axis mark that interval. One mark at zero the other mark at the difference. Slide the mark at zero up the P- wave’s curve until the second mark intersect the S-wave’s curve. once the marks are aligned one can determine the distance Slide the marks on the edge of your paper along the P and S curves of the travel-time scale until marks coincide with both curves. Follow the marked edge of your paper down to the horizontal axis to find the distance to the epicenter Origin time = Arrival time – Travel time Knowing the distance from one station to the epicenter does not locate the epicenter. You need to know the distances from three different stations. To find the epicenter, three circles are drawn on a map, each with the radius equal to the distance from the station. What is a mineral? It occurs naturally. It is solid. It has a definite chemical composition. Its atoms are arranged in an orderly pattern. It is inorganic (was never alive) Cleavage 1. Cleavage – some minerals split along flat, smooth surfaces. For example, mica can be split into thin sheets. 2. Fracture - if a mineral does not cleave, it fractures. When one of these minerals breaks, the fracture is uneven and rough. 3. Conchoidal Fracture – Common in the mineral quartz and the rock obsidian. the fracture is smooth and curved like the inside of a clam shell There are four main physical properties of minerals that can be seen, tested and used to identify minerals: 1. Color – is the most easily observed. However, color is the least useful property for mineral identification. Because many minerals have similar color and impurities can turn colorless minerals into colored minerals. 2. Streak – is the true color of the mineral in its powdered form. (NOTE the streak is not always the same color as the mineral) 3. Luster – the way a mineral’s surface reflects light. It can be metallic (shiny) or non-metallic (glossy, pearly, greasy, dull, earthy etc.) 4. Hardness – a minerals resistance to being scratched, measured using the Mohs’ hardness scale, a relative scale from 1 – 10, one being the softest (talc) and 10 being the hardness (diamond). Earth Science – The study of Earth’s systems and our place in the universe (system – all of the parts, materials, processes and interactions) 3. There are five main branches of Earth Science: 1. Geology: the history, materials, events and structure of the solid Earth. 2. Astronomy: universe – all time, energy, matter and space 3. Meteorology: atmosphere/weather/climate 4. Hydrology: water cycle 5. Oceanography: the processes and properties of oceans I. Observation: using your senses within the environment to gather information. The five senses include: sight, touch, smell, taste, and hearing II. Inference: an interpretation based on observations (Example: if you see footprint fossils, you are making an observation, if you propose the explanation that they were made by a dinosaur, you are inferring) Scientific Notation 1.0 x 10-3 = 0.001 1.0 x 10-2 = 0.01 1.0 x 10-1 = 0.1 1.0 x 100 = 1.0 1.0 x 101 = 10.0 1.0 x 102 = 100.0 1.0 x 103 = 1,000.00 I. Density – is a physical property of a substance (it does not change) meaning that it can be used to identify the substance no matter the size. · Density is related to an object ‘s ability to sink or float Density is the amount of a material contained in a given space, and is expressed as g/cm3 DenseDensity is defined as the mass per unit volume: D = m/V 1. Mass is the amount of matter in an object. Mass is NOT weight. 2. Less denseWeight is the measure of pull of gravity on matter. This is why you weigh more on Earth than you would on the moon. 3. Volume is the amount of space an object takes up. L*W*H = Volume Independent variable – usually indicates a uniform change, such as hours, years or centimeter 1. one knows in advance the expected change of the independent variable Dependent Variable – usually indicates the amount of measured quantity being studied, such as temperature, height or population 1. Dependent variable changes with respect to the independent variable. Formulas students need to know. Density, Rate of change and Gradient Tables’ students need to know. Page 1,2,3,5, 6,7, 10, 11, 14(top) and 16 Coordinate System Equator Latitude · Greatest value of a latitude is 90 degrees · Are called parallels Prime Meridian Longitude The greatest value of an longitude is 180 degrees Are called meridians How does one calculate time? For every 15° east or west of the Greenwich Mean Time (GMT) civil time changes by 1 hour local time is earlier than Greenwich time you are to the west of the Prime Meridian local time is later than Greenwich time you are to the east of the Prime Meridian Types of Isolines Isotherms – Connect points of equal temperature Isobars – connect points of equal air pressure Contour lines - connect points of equal elevation Hachure marks – show depressions Contour interval – the difference in height between two adjacent contour lines V pattern – apex of the V points up stream Profile Vertical Scale Chapter 5 Uniformitarianism – the present is the key to the past Superposition Law of superposition Law of horizontality Law of cross-cutting extrusion intrusion folds faults Fossils – the preserved remains or traces of living things Index fossils – are organisms that existed for a very brief time, but were found over a large area Correlation – a match up of rock layers in different locations by age or by rock type Geologic time scale Evolution of Life Theory of organic evolution Life and Atmosphere Unconformity – a gap in the geologic record caused by the erosion of sediments or rock before they are protected by layer of above Absolute age – numerical age of an object decay product – the remains of a radioactive isotope, which broke down into a naturally lighter element half-life – is the time required for half of an element’s to change into its day product decay-product ratio – the ratio between the radioactive element and its decay product Chapter 6 Weather air pressure – weight of the atmosphere, which is 14.7 lbs barometer – an instrument used to measure air pressure dew point temperature – the temperature which air must be cooled to before it becomes saturated isobars – connects places that have the same air pressure saturated – air is holding as much moisture as it can Relative humidity – expresses how full of moisture the air is Know how wind forms 1. uneven heating of Earth’s surfaces 2. high pressure flows to low pressure 3. low pressure winds turn counterclockwise (convergence), towards the center of the low 4. high pressure winds turn clockwise (divergence), away from the center of the high 5. winds are named by the direction from which they come Coriolis Effect – causes the winds to bend due to the earth rotation Chapter 7 electromagnetic spectrum – radiation energy that the sun produces synoptic weather maps weather station and how to interpret the station weather symbols fronts symbols and how fronts from Air masses and where they form Chapter 8 Water cycle all parts of the water cycle Heat transfer 1. Convection 2. conduction 3. Radiation Insolation – INoming SOLar radiATION Angle of insolation – is a measure of how high the sun is in the sky Duration of insolation – is the length of time sunrise to sunset that the sun appears in the sky Absorption of insolation – taking in the suns energy specific heat – energy required to heat an object water has a higher specific heat than soil, it requires more energy to heat up Reflection of Insolation – insolation is reflected back is not absorbed Greenhouse effect infrared rays from the sun gets trap in gases in the atmosphere causing the temperature to rise, because the heat is trapped Factors that effect climate latitude altitude mountain ranges large bodies of water ocean currents planetary wind belts Chapter 9 Celestial object – objects that appear in the sky but are not part of our atmosphere celestial sphere – the object in the sky appear motion of the stars and planets – rises in the east and sets in the west geocentric model of the universe – earth is the center heliocentric model of the universe – sun is the center rotation – happens in place revolution – moves around an object – the earth revolves around the sun Foucault pendulum – how did it prove that the earth rotates? apparent motion of the sun – appears to be moving but it is not. it is caused by Earth‘s rotation apparent solar day – is the interval of time during which the sun passes from its highest point on one day to its highest point on the next Seasons winter solstice December 21, shortest day of the year spring equinox , March 21, 12 hours of day 12 hours of night Summer solstice, June 21, longest day of the year fall equinox, September 21, 22, or 23, 12 hours of day and 12 hours of night Sun is at its lowest angle of insolation during winter. sun is at its highest angle of insolation during summer. if the north pole leans into the sun than the northern hemisphere is in summer if the north pole leans away from the sun the northern hemisphere is in winter Earth’s tilt is 23.5 degrees, rotates counterclockwise around the sun Higher one latitude the less angle and duration of insolation ones has Chapter 10 phases of the moon – page 164 (know these commit them to memory, you will need to know these phases for your regents Solar eclipses the moon is in the new moon phase a solar eclipse can only occur when the moon is in the new moon phase the moon is between the sun and earth as a result of the moons position it blocks out the sun Lunar eclipse the moon is in the full moon stage a lunar eclipse can only occur when the moon is in the full moon phase the earth is between the sun and moon as a result the earth shadow covers the moon causing an eclipse Tides neap tide – unusually low tide occurs during first and last quarter moons spring tide – unusually high tide occurs during new and full moons tide are caused by gravitational attraction of the moon and sun with earth Ellipse – is defined by two fixed points called the foci eccentricity = distance between the foci length of the major axis Asteroids, meteors, comets Stars, galaxy (earth is in spiral galaxy the Milky way and it is located on an outer arm of the spiral) Rocks Sedimentary Rocks 1. After burial of sediments, over time natural processes and high pressure will cause these sediments to bond and form sedimentary rock. 2. Sedimentary rocks are classified as clastic, chemical or organic depending upon how they were formed. 3. Clastic sedimentary rocks are classified based upon grain (particle) size. 4. Chemically formed sedimentary rocks form from chemical precipitates and evaporites. 5. Organic and chemical sedimentary rocks are primarily identified through composition and texture. 6. Fossils are found almost exclusively in sedimentary rocks. Igneous Rocks 1. Rock types are based upon how they form. Most rocks are composed of one or more minerals. 2. Igneous rocks form by the crystallization (cooling and solidification) of molten magma. 3. Crystal size, mineral composition, density and color are used to identify most igneous rocks. 4. Intrusive (plutonic) rocks can be distinguished from extrusive (volcanic) rocks based on crystal size. 5. Felsic rocks such as granite are commonly found on continents, while mafic rocks such as basalt are more commonly found on the ocean floor. Metamorphic Rocks 1. Metamorphic rocks form through crystallization/recrystallization without melting under high temperature and pressure. 2. Metamorphic rocks are classified according to their texture, composition including foliation (mineral alignment), banding (the separation into distinct distorted layers) and high density. 3. It is possible to infer the parent rock from the mineral composition and structure of most metamorphic rocks. 4. Contact metamorphism is the changing of existing rock by being near liquid rock (magma or lava). 5. Regional metamorphism is the changing of very large (thousands of square kilometers) areas of rock that undergo intense heat and pressure. This is generally associated with mountain building. 6. The rock cycle is a model designed to show how the different rock types are interrelated and the potential pathways rock material may follow in the transformations from one rock typed to another. Reminders: 1. Review the hand-out on the six tasks. 2. YOU MUST be on TIME for the performance test. Once test has begun latecomers will not be allowed to take the test. 3. Calculators and reference tables are provided. Just bring a pen and pencil. 4. The week you are not being tested, report to your regular assignment for that period (lunch). 5. When you come in the day of the exam, place all coats, book etc… on the window sill. 6. Answer all questions in complete sentence and round all numerical answers to the nearest tenth (one decimal place (9.0, 4.2) Luster 1. describes the way light is reflected from the freshly cut surface of a mineral 2. luster falls into two categories metallic or nonmetallic Metallic 1. looks like metal 2. have a hard shiny look Nonmetallic 1. can be shiny but the mineral lacks the metallic appearance 2. does not look like metal Streak 1. is the true color of the mineral in powered form 2. one performs a streak where the mineral by rubbing the mineral on a streak plate 3. After rubbing the mineral on the streak plate you should see a color if you do not see a color rub your finger on the area that us just rub the mineral over. 4. if your finger come back with nothing on it then the mineral is none to white 5. it is important to note the streak may not match the physical color of the mineral Hardness 1. hardness of glass if 5.5 2. do to a hardness test you scratch a piece of glass 3. lay the piece of glass flat on the desk and hold it in place 4. than press the mineral onto the glass and try to scratch the glass (don’t be shy you may have to press a little hard) 5. if the mineral scratches the glass the than the minerals hardness is harder than glass 6. if the mineral does not scratch the glass than the minerals hardness is less than glass Cleavage 1. the mineral breaks readily along a flat surface 2. cleavage also occurs a angles, but always along a flat surface Cleavage Streak Hardness* Luster Specific Characteristics Mineral Does not show Cleavage Colored As hard as glass or harder than glass Metallic Streak: black Color: black Hardness: 5.5-5.6 Magnetite Nonmetallic Streak: yellow Color: yellow Hardness: 1.5-2.5 Sulfur None or White Not as hard as glass Nonmetallic Streak: none to white Color: green to Yellow Hardness: 6.5-7.0 Olivine Nonmetallic Streak: white Color: white to Gray Hardness: 2.0 Alabaster (Gypsum) Shows Cleavage Colored As hard as glass or harder than glass Nonmetallic Streak: pale green Color: dark green to black Hardness: 5.0-6.0 Cleavage: 2 planes not a right angles Hornblende Metallic Streak: black to silver gray Color: gray-black Hardness: 5.5-5.6 Cleavage: 3 planes at right angles Galena None or White Not as hard as glass Nonmetallic Streak: none to white Color: white to pink Hardness: 6.0 Cleavage: 2 planes at right angles Orthoclase (Feldspar) Nonmetallic Streak: white Color: varies, may be transparent Hardness: 3.0 Cleavage 3 planes not at right angles Calcite posted by James | 10:10 AM |
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