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Earth and Space Science. By Gabby Guyer. Chapter 1. Sect 1: exploring earths surface. Earths topography is made up of landforms that have elevation and relief, such as plains, mountains, and plateaus.
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Earth and Space Science By Gabby Guyer
Sect 1: exploring earths surface • Earths topography is made up of landforms that have elevation and relief, such as plains, mountains, and plateaus. • The atmosphere, hydrosphere, and biosphere surround Earth’s rocky outer layer, the lithosphere.
Sect 2: Mapping Earth’s Surface • Maps and globes are drawn to scale to show features on Earth’s surface • The grid of latitude and longitude lines can be used to locate points on Earth’s surface.
Sect 3: Maps in the Computer Age • Instruments carried aboard satellites in orbit around Earth make pictures of the surface called satellite images. • Computers are used to store and display the information used in making maps.
Sect 4: Topographic Maps • Topographic maps portray the elevation, relief, and slope of the landforms in an area. • Contour lines are used on a topographic map to show elevation and relief. • The contour interval of a topographic map is the amount that elevation increases or deceases between contour lines. • In addition to showing elevation and relief, topographic maps include a variety of other natural and human-made features.
Sect 1: Properties of Minerals • A mineral is a naturally occurring inorganic solid that has a distinct chemical composition and crystal shape. • Each mineral can be identified by its own physical and chemical properties. • Some of the properties of minerals include hardness, color, streak, luster, density, cleavage and fracture, and crystal structure. Hardness is measured by the Mohs hardness scale. • Minerals usually consist of two or more elements joined together in a compound.
Sect 2: How minerals Form • Minerals form inside Earth through crystallization as magma or lava cools. • Minerals form on Earth’s surface when materials dissolved in water crystallization through evaporation. • Mineral deposits form on the ocean floor from solutions heated by magma. The hot-water solutions containing minerals erupt through chimneys on the ocean floor, then crystallization when they come in contact with cold sea water.
Sect 3: Mineral Resources • Minerals are useful as the source of all metals, gemstones, and of many other materials. • Geologists locate ore deposits by prospecting- looking for certain features on and beneath Earth’s surface. • Ores can be removed from the ground through open pit mines, strip mines, or shaft mines. • Smelting is the process of heating an ore to extract a metal.
Sect 1: Classifying Rocks • A rock is a hard piece of Earth’s crust. • Geologists classify rocks according to their color, texture, mineral composition, and origin. • The three kinds of rocks are igneous, sedimentary, and metamorphic.
Section 2: Igneous Rocks • Igneous rocks form from magma or lava • Igneous rocks are classified according to their origin, texture, and composition.
Section 3: Sedimentary Rocks • Most sedimentary rocks form from sediments that are compacted and cemented together. • The three types of sedimentary rocks are clastic rocks, organic rocks, and chemical rocks.
Section 4: Rocks From Reefs • When corals die, their skeletons remain. More corals grow on top of them, slowly forming a reef.
Sect 5: Metamorphic Rocks • In a process that takes place deep beneath the surface, heat and pressure can change any type of rock into metamorphic rock. • Geologists classify metamorphic rock according to whether the rock is foliated or nonfoliated.
Sect 6:The Rock Cycle • The series of processes on and beneath Earth’s surface that change rocks from one type of rock to another is called the rock cycle.
Sect 1: Earth’s Interior • Earth’s interior is divided into the crust, the mantle, the outer core, and the inner core. • The lithosphere includes the crust and the rigid upper layer of the mantle; beneath the lithosphere lies the soft layer of the mantle called the asthenosphere.
Sect 2: Convection Currents and the Mantle • Heat can be transferred on three ways: radiation, conduction, and convection. • Differences of temperature and density within a fluid cause convection currents.
Sect 3: Drifting Continents • Alfred Wegener developed the idea that the continents were once joined and have since drifted apart. • Most scientists rejected Wegner’s theory because he could not identify a force that could move the continents.
Sect 4: Sea-Floor Spreading • In sea-floor spreading, molten material forms new rock along the mid-ocean ridge. • In subduction, the ocean floor sinks back to the mantle beneath deep ocean trenches.
Sect 5: The Theory of Plate Tectonics • The theory of plate tectonics explains plate movements and how they cause continental drift . • Plates slip past each other at transform boundaries, move apart at divergent boundaries, and come together at convergent boundaries.
Sect 1: Earth’s Crust in Motion • Stresses on Earth’s crust produce compression, tension, and shearing in rock. • Faults are cracks in Earth’s crust that result from stress. • Faulting and folding of the crust cause mountains and other features to form on the surface.
Sect 2: Measuring Earthquakes • As seismic waves travel through Earth, they carry the energy of an earthquake from the focus to the surface. • Earthquakes produce two types of seismic waves, P waves and S waves, that travel out in all directions from the focus of an earthquake. • Today, the moment magnitude scale is used to determine the magnitude of an earthquake. Other scales that geologists have used to rate earth-quakes include the Mercalli scale and the Richter scale.
Sect 3: Earthquake Hazards and Safety • Earthquakes can damage structures through tsunamis, landslides or avalanches, and shaking or liquefaction of the ground. • New buildings can be designed to withstand earthquakes; old buildings can be modified to make them more earthquake- resistant. • For personal safety indoors during an earthquake, drop, cover, and hold under a desk or table, or against an interior wall.
Sect 4: Monitoring Faults • Geologists used instruments to measure deformation and stress along faults. • Scientists determine earthquake risk by monitoring active faults and by studying faults where past earthquakes have occurred.
Sect 1: Volcanoes and Plate Tectonics • A volcano is an opening on Earth’s surface where magma escapes from the interior. Magma that reaches Earth’s surface is called lava. • The constructive force of volcanoes adds new rock to existing land and forms new islands. • Most volcanoes occur near the boundaries of Earth’s plates and along the edges of continents, in island arcs, or along mid-ocean ridges.
Sect 2: Volcanic Activity • An eruption occurs when gases trapped in magma rush through an opening at the Earth’s surface, carrying magma with them • Volcanoes can erupt quietly or explosively, depending on the amount of dissolved gases in the magma and on how think or runny the magma is. • When magma heats water underground, hot springs and geyser form. • Volcano hazards include pyroclastic flows, avalanches of mud, damage from ash, lava flows, flooding, and deadly gases.
Sect 3: Volcanic Landforms • Lava and other volcanic materials on the surface create shield volcanoes, cinder cones, composite volcanoes, and plateaus. • Magma that hardens beneath the surface creates batholiths, dome mountains, dikes, and sills, which are eventually exposed when the covering rock wears away.
Sect 1: Rocks and Weathering • Rock weathers, or wears down, when it is exposed to air, water, weather, and living things at Earth’s surface. • Mechanical weathering breaks rock into smaller pieces. The agents of mechanical weathering include freezing and thawing, release of pressure, growth of plants, actions of animals, and abrasion. • Chemical weathering changes the mineral content of rock. The agents of chemical weathering are water, oxygen, carbon dioxide, living organisms, and acid rain. • Climate and rock type determine how fast weathering occurs.
Sect 2: Soil Formation and Composition • Soil is made of small particles of rock mixed with the decaying remains or organisms. • Soil forms in layers called horizons as bedrock weathers and organic materials build up. • The three soil horizons are the A horizon, the B horizon, and the C horizon. The A horizon is made up of topsoil, which is rich in humus. The B horizon consists of clay and other particles washed down from the A horizon, but little humus. The C horizon is made up of partly weathered rock without clay or humus. • Plants and animals break up and mix the soil, and also add the organic materials that form humus.
Sect 3: Soil Conservation • Land is a limited resource. All the people on Earth must share land for agriculture, development, mining, and other uses. • Soil can be eroded away and its fertility can be decreased by improper farming practices. • Soil can be conserved and its fertility can be maintained by using various methods of soil conservation.
Sect 4: Waste Disposal and Recycling • Three ways of handling solid waste are to bury it, burn it, or recycle it. • One way to reduce solid waste is to practice the “three R’s” – reduce, reuse, and recycle. • Hazardous wastes are materials that can threaten human health and safety or harm the environment if not properly disposed.
Sect 1: Changing Earth’s Surface • Weathering, erosion, and deposition act to wear down and build up Earth’s surface. • Gravity pulls sediment downhill in the process of mass movement. There are four main types of mass movement: landslides, mudslides, slump, and creep.
Sect 2: Water Erosion • Moving water is the major force of erosion that has shaped Earth’s land surface. • A river may form V-shaped valleys, waterfalls, meanders, oxbow lakes, and flood plains. • When a river slows down, it deposits some of the sediment load it carries, forming features such as alluvial fans and deltas.
Sect 3: The Force of Moving Water • When gravity pulls water down a slope, water’s potential energy changes to kinetic energy, and it does work. • Most sediment washes or falls into streams, or is eroded from the streambed by abrasion. • The greater a river’s slope or volume of flow, the more sediment it can erode.
Sect 4: Glaciers • The two kinds of glaciers are valley glaciers and continental glaciers. • Glaciers erode the land through plucking and abrasion. Melting glaciers deposit sediment.
Sect 5: Waves • The energy of ocean waves comes from wind blowing across the water’s surface and transferring energy to the water. • Ocean waves hitting land cause erosion through impact and abrasion. Waves also move and deposit sediment along the shore.
Sect 5: Wind Erosion • Wind causes erosion mainly through deflation, the blowing of surface materials. • Landforms created by wind deposition include sand dunes and loess deposits.
Sect 1: Fossils • Most fossils form when living things die and are quickly buried by sediment, which eventually hardens and preserves parts of the organisms. • The major kinds of fossils include petrified remains, molds, casts, carbon films, trace fossils, and preserved remains. • The fossil record shows that many different organisms have lived on Earth at different times and that groups of organisms have changed over time.
Sect 2: Finding the Relative Age of Rocks • The law of superposition can be used to determine the relative ages pf rock layers. • Scientists also study faults, intrusions, and extrusions to find the relative ages of rock layers. • Index fossils are useful in dating rock layers.
Sect 3: Radioactive Dating • During radioactive decay, the atoms of one element decay into atoms of another element. • Scientists use radioactive dating to determine the absolute ages of rocks.
Sect 4: The Geologic Time Scale • The basic divisions of the geologic time scale are eras, periods, and epochs.
Sect 5: Earth’s History • A great number of different kinds of living things evolved during the “Cambrian explosion” at the beginning of the Paleozoic Era. • During the Permian Period, the continents joined to form the super continent Pangaea.
