| A | B |
|---|
| scientific method | posing questions, developing and testing hypotheses, and drawing conclusions |
| hypothesis | A possible explanation for a set of observations or an answer to a scientific question |
| scientific theory | A well-tested concept that explains a wide range of observations |
| geologists | A scientist who studies the forces that make and shape planet Earth |
| oceanographers | A scientist who studies Earth's oceans |
| meteorologists | Scientists who study the causes of weather and try to predict it |
| astronomers | Scientists who study the universe |
| topography | The shape of land determined by elevation, relief and landforms |
| relief | The difference in elevation between the highest and lowest parts of an area |
| plateau | A landform that has a more or less level surface and is elevated high above sea level |
| core | Earth's dense center, made up of the solid innner core and the molten outer core |
| mantle | The layer of hot, solid material between Earth's crust and core |
| crust | The layer of rock that forms Earth's outer surface |
| latitude | The distance north and south from the equator, measured in degrees |
| longitude | The distance in degrees east and west of the prime meridan |
| pixel | The tiny dots in a satellite image |
| Mohs hardness scale | a scale ranking ten minerals from softest to hardest; used in testing the hardness of minerals |
| streak | the color of a mineral's powder |
| luster | the way a mineral reflects light from its surface |
| density | the amount of mass in a given space; mass per unit volume |
| hardness | how hard a mineral is |
| gemstone | a hard, colorful mineral that has a brilliant or glossy luster |
| ore | rock that contains a metal or economically useful mineral |
| smelting | the process by which ore is melted to separate the useful metal from the other elements |
| inorganic | not formed from living things or the remains of living things |
| igneous rock | a type of rock that forms from the cooling of molten rock at or below the surface |
| sedimentary rock | a type of rock that forms when particles from other rocks or the remains of plants and animals are pressed and cemented together |
| metamorphic rock | a type of rock that forms from an existing rock that is changed by heat, pressure, or chemical reactions |
| extrusive rock | igneous rock that forms from lava on Earth's surface |
| intrusive rock | igneous rock that forms when magma hardens beneath Earth's surface |
| porphyritic texture | an igneous rock texture in which large crystals are scattered on a background of much smaller crystals |
| compaction | the process by which sediments are pressed together under their own weight |
| cementation | the process by which dissolved minerals crystallize and glue particles of sediment together into one mass |
| atoll | a ring-shaped coral island found far from land |
| fringing reef | reefs that lie close to shore, separated from land by shallow water |
| barrier reef | reefs that lie far out, at least 10 km from land |
| the rock cycle | a series of processes on the surface and inside Earth that slowly changes rocks from one kind to another |
| prospector | anyone who searches, or prospects for an ore deposit |
| radiation | the direct transfer of energy through empty space by electromagnetic waves |
| conduction | the transfer of heat from one substance to another by direct contact of particles of matter |
| convection | the transfer of heat bymovements of a fluid |
| convection current | the movement of a fluid, caused by differences in temperature, that transfers heat from one part of the fluid to another |
| Pangaea | the name of the single landmass that broke apart 225 million years ago and gave rise to today's continents |
| continental drift | the hypothesis that the continents slowly move across Earth's surface |
| mid-ocean ridge | the undersea mountain chain where new ocean floor is produced; a divergent plate boundary |
| sea-floor spreading | the process by which molten material adds new oceanic crust to the ocean floor |
| deep-ocean trench | a deep valley along the ocean floor through which oceanic crust slowly sinks toward the mantle |
| transform boundary | a plate boundary where two plates move past each other in opposite directions |
| divergent boundary | a plate boundary where two plates move away from each other |
| rift valley | a deep valley that forms where two plates move apart |
| convergent boundary | a plate boundary where two plates move toward each other |
| shearing | stress that pushes a mass of rock in opposite directions |
| tension | stress that stretches rock so that it becomes thinner in the middle |
| compression | stress that squeezes rock unitl it folds and breaks |
| deformation | a change in the volume or shape of Earth's crust |
| strike-slip fault | a type of fault where rocks on either side move past each other sideways with little up-or-down motion |
| normal fault | a type of fault where the hanging wall slides downward; caused by tension in the crust |
| anticline | an upward fold in rock formed by compression of Earth's crust |
| syncline | a downward fold in rock formed by compression in Earth's crust |
| focus | the point beneath Earth's surface where rock breaks under stress and causes an earthquake |
| epicenter | the point on Earth's surface directly above the earthquake's focus |
| P waves | the type of waves that compress and expand the ground |
| S Waves | the type of waves that move the ground up and down or side to side |
| surface waves | the type of seismic wave that forms when P waves and S waves reach Earth's surface |
| Mercalli scale | a scale that rates earthquakes according to their intensity and how much damage they cause |
| Richter scale | a scale that rates seismic waves as measured by a mechanical seismograph |
| moment magnitude scale | a scale that rates earthquakes by estimating the total energy released by an earthquake |
| liquefaction | the process by which an earthquake's violent movement suddenly turns loose soil into liquid mud |
| aftershock | an earthquake that occurs after a larger earthquake in the same area |
| tsunamis | a giant wave caused by an earthquake on the ocean floor |
| base-isolated building | a building mounted on bearings designed to absorb the energy of an earthquake |
| magma | the molten mixture of rock-forming substances, gases, and water that makes up part of Earth's mantle |
| lava | magma that reaches the surface; also the rock formed when liquid lava hardens |
| Ring of Fire | a major belt of volcanoes that rims the Pacific Ocean |
| hot spot | an area where magma from deep within the mantle melts through the crust above it |
| pipe | a long tube through which magma move from the magma chamber to Earth's surface |
| vent | the opening through which molten rock and gas leave a volcano |
| crater | a bowl-shaped area that forms around a volcano's central opening |
| active | said of a volcano that is erupting or has shown signs of erupting in the near future |
| dormant | said of a volcano that does not show signs of erupting in the near future |
| extinct | said of a volcano that is unlikely to erupt again |
| hot spring | a pool fromed by groundwater that has risen to the surface after being heated by a nearby body of magma |
| geyser | a type of hot spring that builds up pressure underground and erupts at regular intervals as a fountain of water and steam |
| geothermal energy | heat energy in Earth's interior from water or steam that has been heated by magma |
| shield volcano | a wide, gently sloping mountain made of layers of lava and formed by quiet eruptions |
| cinder cone | a steep, cone-shaped hill or mountain made of volcanic ash, cinders, and bombs piled up around a volcano's opening |
| composite volcano | a tall, cone-shaped mountain in which layers of lava alternate with layers of ash and other volcanic materials |
| mechanical weathering | type of weathering in which rock is physically broken down into smaller pieces |
| abrasion | the grinding away of rock by rock particles carried by water, ice, wind, or gravity |
| ice wedging | process that splits rock when water seeps into cracks, then freezes and expands |
| chemical weathering | the process that breaks down rock through chemical changes |
| permeable | a material that is full of tiny, connected air spaces that allow water to seep through it |
| soil | the loose, weathered material on Earth's surface in which plants can grow |
| bedrock | the solid layer of rock beneath the soil |
| humus | a dark-colored substance that forms as plant and animal remains decay |
| loam | rich, fertile soild that is made up of equal parts of clay, sand, and silt |
| soil horizon | a layer of soil that differs in color and texture from the layers above or below |
| topsoil | mixture of humus, clay, and other materials that forms the crumbly, topmost layer of soil |
| subsoil | the layer of soil beneath the topsoil that contains mostly clay and other minerals |
| litter | the loose layer of dead plant leaves and stems on the surface of the soil |
| decomposers | an organism that breaks down wastes and dead organisms |
| desertification | the advance of desertlike conditions into areas that previously were fertile |
| sod | a thick mass of grass roots and soil |
| dust bowl | the area of the Great Plains where wind erosion caused soil loss during the 1930s |
| soil conservation | the management of soil to prevents its destruction |
| crop rotation | the planting of different crops in a field each year |
| leachate | water that has passed through buried wastes in a landfill |
| incineration | the burning of solid waste |
| recycling | the process of reclaiming and reusing raw materials |
| hazardous waste | a material that can be harmful if it is not properly disposed of |
