Earth Science - Middle School

Earth science will be a breeze once you master these essential terms. This comprehensive vocabulary list covers core topics like weather and climate, natural disasters, ecology and conservation, plate tectonics, types of rock, oceanography, and more. Best of all, you can mine this list again and again — it's a renewable resource.
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words only definitions & notes
  1. abyssal
    relating to ocean depths from 2000 to 5000 meters
  2. abyssal zone
    the deep sea (2000 meters or more) where there is no light
  3. accumulation
    an increase by natural growth or addition
  4. acidification
    the process of shifting toward the lower end of the pH scale
  5. acid rain
    precipitation with toxic gas emissions combined with water
  6. active
    (of e.g. volcanos) erupting or liable to erupt
  7. adaptation
    the process of adjusting or conforming to new conditions
  8. aerosol
    a cloud of solid or liquid particles in a gas
  9. aftershock
    a tremor following the main tremor of an earthquake
  10. agriculture
    the practice of cultivating the land or raising stock
  11. air mass
    a large body of air with uniform characteristics horizontally
  12. air pollution
    pollution of the atmosphere
  13. air pressure
    the pressure exerted by the atmosphere
  14. Alfred Lothar Wegener
    German geophysicist who proposed the theory of continental drift (1880-1930)
  15. alternative energy
    energy derived from sources that do not use up natural resources or harm the environment
  16. altitude
    elevation above sea level or above the earth's surface
  17. altocumulus
    a cumulus cloud at an intermediate altitude of 2 or 3 miles
  18. altostratus
    a stratus cloud at an intermediate altitude of 2 or 3 miles
  19. anemometer
    a gauge for recording the speed and direction of wind
  20. Antarctic Ocean
    the southern waters surrounding Antarctica
  21. aphotic
    lacking light; especially not reached by sunlight
  22. aquaculture
    raising fish or shellfish or growing water plants for food
  23. aquifer
    underground layer of rock or sand that yields groundwater
  24. Archean
    relating to the eon from about 4.0 to 2.5 billion years ago
  25. Arctic Ocean
    ice covered waters surrounding the North Pole
  26. asthenosphere
    the zone of Earth's mantle that lies below the lithosphere
  27. Atlantic Ocean
    the 2nd largest ocean
  28. atmosphere
    the mass of air surrounding the Earth
  29. atmospheric pressure
    the pressure exerted by the atmosphere
  30. avalanche
    a slide of large masses of snow, ice and mud down a mountain
  31. axis
    the center around which something rotates
  32. barometer
    an instrument that measures atmospheric pressure
  33. bed
    (geology) a stratum of rock (especially sedimentary rock)
  34. beryl
    the chief source of beryllium
  35. big bang theory
    (cosmology) the theory that the universe originated sometime between 10 billion and 20 billion years ago from the cataclysmic explosion of a small volume of matter at extremely high density and temperature
  36. biodegradable
    capable of being decomposed
  37. biodiversity
    the variety of plant and animal life in a habitat
  38. biomass
    the total amount of living matter in a given unit area
  39. biome
    major ecological community with distinct climate and flora
  40. biosphere
    the regions of the Earth where living organisms exist
  41. biotic
    of or relating to living organisms
  42. bituminous coal
    fossil fuel rich in tarry hydrocarbons
  43. blizzard
    a weather event with widespread snowfall and strong winds
  44. boulder
    a large smooth mass of rock detached from a place of origin
  45. breaker
    waves breaking on the shore
  46. Cambrian
    the geologic period from about 541 to 485 million years ago
  47. canyon
    a ravine formed by a river in an area with little rainfall
  48. carbon
    an abundant nonmetallic element in all organic compounds
  49. carbon cycle
    the organic circulation of carbon from the atmosphere into organisms and back again
  50. carbon dioxide
    a colorless, odorless greenhouse gas essential for photosynthesis
  51. Celsius scale
    a temperature scale that defines the freezing point of water as 0 degrees and the boiling point of water as 100 degrees
  52. Cenozoic
    the current geologic era, starting about 66 million years ago
  53. chlorofluorocarbon
    a fluorocarbon with chlorine
  54. cinder
    a fragment of incombustible matter left after a fire
  55. circulation
    free movement or passage
  56. cirrocumulus
    a cloud at a high altitude consisting of a series of regularly arranged small clouds resembling ripples
  57. cirrostratus
    a thin uniform layer of hazy cloud at high altitude
  58. cirrus
    a wispy white cloud at a high altitude
  59. clastic
    of or belonging to or being a rock composed of fragments of older rocks (e.g., conglomerates or sandstone)
  60. cleavage
    the act of splitting
  61. climate
    the weather in some location averaged over a period of time
  62. climate change
    a shift in the world's average weather and temperature
  63. cloud
    a visible mass of water or ice particles suspended at a considerable altitude
  64. coal
    fossil fuel consisting of carbonized vegetable matter
  65. coarse-grained
    not having a fine texture
  66. coastal
    located on or near or bordering on a shore
  67. cold front
    the front of an advancing mass of colder air
  68. combustion
    a reaction of a substance with oxygen to give heat and light
  69. commensalism
    when one organism benefits from another without damaging it
  70. community
    group of interdependent organisms living in the same region
  71. compaction
    an increase in the density of something
  72. composition
    the way in which someone or something is put together
  73. compression
    the process of becoming smaller or pressed together
  74. condensation
    process of changing from a gas to a liquid or solid state
  75. conduction
    the transmission of heat or electricity or sound
  76. conglomerate
    a composite rock made up of particles of varying size
  77. conservation
    careful management of the environment and natural resources
  78. continent
    one of the large landmasses of the earth
  79. continental
    of or relating to or characteristic of a continent
  80. continental drift
    the gradual movement of very large land masses
  81. continental shelf
    the relatively shallow seabed surrounding a continent
  82. continental slope
    the steep descent of the seabed from the continental shelf to the abyssal zone
  83. convection
    transfer of heat caused by molecular motion in liquid or gas
  84. convergence
    the occurrence of two or more things coming together
  85. copper
    a ductile malleable reddish-brown corrosion-resistant diamagnetic metallic element; occurs in various minerals but is the only metal that occurs abundantly in large masses; used as an electrical and thermal conductor
  86. coral reef
    a reef consisting of coral consolidated into limestone
  87. core
    the central part of the Earth
  88. Coriolis effect
    (physics) an effect whereby a body moving in a rotating frame of reference experiences the Coriolis force acting perpendicular to the direction of motion and to the axis of rotation; on Earth the Coriolis effect deflects moving bodies to the right in the northern hemisphere and to the left in the southern hemisphere
  89. crater
    a bowl-shaped geological formation at the top of a volcano
  90. crest
    the top or extreme point of something
  91. Cretaceous
    relating to the period from about 145 to 66 million years ago
  92. crude oil
    a dark oil consisting mainly of hydrocarbons
  93. crust
    the outer layer of the Earth
  94. crustal movement
    movement resulting from or causing deformation of the earth's crust
  95. crystal
    a solid having a highly regular atomic structure
  96. crystalline
    consisting of or containing or of the nature of crystals
  97. crystallization
    the formation of crystals
  98. cumulonimbus
    a dark cloud of great vertical extent charged with electricity; associated with thunderstorms
  99. cumulus
    a globular cloud
  100. current
    a steady flow of a fluid or gas
  101. cycle
    a periodically repeated sequence of events
  102. cyclone
    an atmospheric system in which air circulates rapidly
  103. dam
    a barrier constructed to contain the flow of water
  104. debris
    the remains of something that has been destroyed
  105. decay
    the organic phenomenon of rotting
  106. decomposition
    the organic phenomenon of rotting
  107. deforestation
    the removal of trees
  108. deformation
    alteration in the shape or dimensions of an object as a result of the application of stress to it
  109. density
    the amount per unit size
  110. depletion
    the state of being used up
  111. deposit
    the phenomenon of sediment or gravel accumulating
  112. deposition
    the natural process of laying something down
  113. depression
    a sunken or lowered geological formation
  114. desert
    arid land with little or no vegetation
  115. desertification
    a gradual transformation into arid, uninhabitable land
  116. destabilize
    make unsturdy, insecure, or less able to function smoothly
  117. Devonian
    relating to the period from about 419 to 359 million years ago
  118. dew point
    the temperature at which the water vapor in the air becomes saturated and condensation begins
  119. diffusion
    the act of dispersing something
  120. distribution
    the property of being scattered about over a range or area
  121. divergence
    moving away in different direction from a common point
  122. dormant
    not erupting but not extinct
  123. drainage basin
    the entire geographical area drained by a river and its tributaries; an area characterized by all runoff being conveyed to the same outlet
  124. drought
    a shortage of rainfall
  125. dust storm
    a windstorm that lifts up clouds of dust or sand
  126. earth
    the third planet from the sun
  127. earthquake
    vibration from underground movement along a fault plane
  128. ecology
    the environment as it relates to living organisms
  129. ecosystem
    organisms interacting with their physical environment
  130. element
    a substance that cannot be separated into simpler substances
  131. elevation
    distance of something above a reference point
  132. El Nino
    a warm ocean current in the Pacific that sets off a chain of weather events
  133. emission
    the act of causing to flow forth
  134. energy
    any source of usable power
  135. environment
    the area in which something exists or lives
  136. environmental
    of or relating to the external conditions or surroundings
  137. eon
    the longest unit of geological time
  138. epicenter
    a point on the Earth's surface directly above an earthquake
  139. epoch
    a unit of geological time that is divided into ages
  140. equator
    an imaginary line around the Earth forming a great circle
  141. era
    a major division of geological time
  142. erosion
    the process of wearing or grinding something down
  143. eruption
    the sudden occurrence of a violent discharge
  144. estuary
    the wide part of a river where it nears the sea
  145. eutrophication
    nutrient saturation of water leading to oxygen depletion
  146. evaporation
    the process of becoming a suspension of particles in the air
  147. exosphere
    the outermost atmospheric layer
  148. extinction
    the state of being no longer in existence
  149. extraction
    taking out something
  150. extrusive
    forced while molten through cracks in the earth's surface
  151. eye
    an area that is approximately central within some larger region
  152. Fahrenheit
    of or relating to a temperature scale proposed by the inventor of the mercury thermometer
  153. Fahrenheit scale
    a temperature scale that defines the freezing point of water as 32 degrees and the boiling point of water a 212 degrees
  154. fault
    a crack in the earth's crust resulting from displacement
  155. feedback
    the process in which output of a system is returned to input
  156. feldspar
    any of a group of hard crystalline minerals that consist of aluminum silicates of potassium or sodium or calcium or barium
  157. fertilizer
    any substance used to improve the quality of soil
  158. fine-grained
    consisting of fine particles
  159. fissure
    a long narrow depression in a surface
  160. flash flood
    a sudden and great flow of water in a short period of time
  161. flint
    a hard kind of stone
  162. flood
    the rising of a body of water and its overflowing onto land
  163. flood plain
    a low plain adjacent to a river that is formed chiefly of river sediment and is subject to flooding
  164. fluorescence
    light emitted during absorption of radiation of some other (invisible) wavelength
  165. fluorite
    a soft mineral that is fluorescent in ultraviolet light
  166. folding
    a geological process that causes a bend in a stratum of rock
  167. foliated
    having thin leaflike layers or strata
  168. foliation
    (geology) the arrangement of leaflike layers in a rock
  169. forecast
    a prediction about how something will develop
  170. forest fire
    an uncontrolled fire in a wooded area
  171. formation
    (geology) a distinct unit of rocks or layers
  172. fossil
    the remains of a plant or animal from a past geological age
  173. fossil fuel
    energy-producing substance derived from preserved organisms
  174. fracture
    a crack in the earth's crust
  175. fresh water
    water that is not salty
  176. front
    phenomenon at the boundary between two different air masses
  177. gaseous
    existing as or having characteristics of a gas
  178. gemstone
    a crystalline rock that can be cut and polished for jewelry
  179. geochemistry
    the science that studies the earth's physical composition
  180. geode
    a hollow rock with an interior cavity lined with crystals
  181. geologic
    of or relating to the study of Earth and its structure
  182. geologist
    a specialist in the history of the Earth recorded in rocks
  183. geology
    science of the history of the earth as recorded in rocks
  184. geopolitical
    relating to the influence of geography on politics and global affairs
  185. geosphere
    the solid part of the Earth
  186. geothermal energy
    energy derived from the heat in the interior of the earth
  187. geyser
    a spring that discharges hot water and steam
  188. glacier
    a slowly moving mass of ice
  189. global warming
    a rise in the average temperature of the earth's atmosphere
  190. Gondwanaland
    a hypothetical continent that (according to plate tectonic theory) broke up later into India and Australia and Africa and South America and Antarctica
  191. grain
    the physical composition of something
  192. granite
    a type of igneous rock with a visibly crystalline texture
  193. grassland
    land where grass or grasslike vegetation grows and is the dominant form of plant life
  194. gravel
    rock fragments and pebbles
  195. gravity
    the force of attraction between all masses in the universe
  196. greenhouse effect
    warming due to solar radiation trapped by the atmosphere
  197. greenhouse gas
    a substance in the air that warms a planet by trapping heat
  198. habitat
    the type of environment in which an organism normally lives
  199. hailstone
    small pellet of ice that falls during a hailstorm
  200. hailstorm
    a storm during which hail falls
  201. half-life
    the time required for something to fall to half its initial value (in particular, the time for half the atoms in a radioactive substance to disintegrate)
  202. hardness
    the property of being rigid and resistant to pressure
  203. hazard
    a source of danger
  204. heat
    a form of energy transferred by a difference in temperature
  205. heat wave
    a period of unusually hot weather
  206. hot spot
    a point of relatively intense heat or radiation
  207. hot spring
    a natural spring of water at a temperature of 70 F or above
  208. humidity
    wetness in the atmosphere
  209. hurricane
    a severe tropical cyclone usually with heavy rains and winds
  210. hydrocarbon
    an organic compound containing only carbon and hydrogen
  211. hydroelectricity
    electricity produced by water power
  212. hydrology
    the branch of geology that studies water on the earth and in the atmosphere
  213. hydrosphere
    the watery layer of the earth's surface
  214. hygrometer
    measuring instrument for measuring the relative humidity of the atmosphere
  215. ice age
    a period when glaciers cover much of the Earth's surface
  216. iceberg
    a large frozen mass floating at sea
  217. ice cap
    a mass of ice and snow that permanently covers a large area of land (e.g., the polar regions or a mountain peak)
  218. ice floe
    a flat mass of ice floating at sea
  219. ice storm
    a storm with freezing rain that leaves everything glazed with ice
  220. igneous
    produced by the action of fire or intense heat
  221. impact
    a forceful consequence; a strong effect
  222. index fossil
    a fossil known to have lived in a particular geologic age that can be used to date the rock layer in which it is found
  223. Indian Ocean
    the 3rd largest ocean
  224. industrialization
    the development of commercial enterprise
  225. infiltration
    the slow passage of a liquid through a medium
  226. inorganic
    relating or belonging to the class of compounds not having a carbon basis
  227. intrusive
    forced while molten into cracks between layers of other rock
  228. irrigation
    the act of supplying dry land with water by artificial means
  229. isobar
    (meteorology)an isogram connecting points having equal barometric pressure at a given time
  230. isotherm
    (meteorology) an isogram connecting points having the same temperature at a given time
  231. jet stream
    a high-speed air current blowing constantly high above the earth
  232. Jurassic
    relating to the period from about 201 to 145 million years ago
  233. lahar
    an avalanche of volcanic water and mud down the slopes of a volcano
  234. landfill
    an area where waste is disposed of by burying it underground
  235. landslide
    the descent of a large mass of dirt and rock down a slope
  236. latitude
    an imaginary line around the Earth parallel to the equator
  237. Laurasia
    a hypothetical continent that (according to plate tectonic theory) broke up later into North America and Europe and Asia
  238. lava
    rock that in its molten form issues from volcanos
  239. levee
    an embankment built to prevent a river from overflowing
  240. lightning
    an electric discharge between clouds or from cloud to earth
  241. lightning rod
    a metallic conductor that is attached to a high point and leads to the ground; protects the building from destruction by lightning
  242. limestone
    a sedimentary rock consisting mainly of calcium that was deposited by the remains of marine animals
  243. lithosphere
    the solid part of the Earth
  244. loam
    a rich soil consisting of sand, clay and organic materials
  245. loess
    a fine accumulation of clay and silt deposited by the wind
  246. longitude
    the angular distance from the prime meridian at Greenwich
  247. luster
    the property of something that shines with reflected light
  248. maelstrom
    a powerful circular current of water
  249. magma
    molten rock in the earth's crust
  250. magnetism
    attraction for iron
  251. magnitude
    the property of relative size or extent
  252. malachite
    a green mineral used for jewelry, ornaments, and copper ore
  253. mantle
    the layer of the earth between the crust and the core
  254. maritime
    bordering on or living near the sea
  255. matter
    that which has mass and occupies space
  256. mesosphere
    the atmospheric layer between the stratosphere and the thermosphere
  257. Mesozoic
    the geologic era from about 252 to 66 million years ago
  258. metal
    a chemical element or alloy that is usually a shiny solid
  259. metamorphic
    having undergone transformation by pressure, heat, etc.
  260. meteorite
    a stony or metallic object from space that hits the earth
  261. meteorologist
    a specialist who studies weather conditions
  262. meteorology
    the earth science dealing with phenomena of the atmosphere
  263. methane
    a colorless, odorless gas used as a fuel
  264. mica
    any of various minerals consisting of hydrous silicates of aluminum or potassium etc. that crystallize in forms that allow perfect cleavage into very thin leaves; used as dielectrics because of their resistance to electricity
  265. microbe
    a minute life form, especially one that causes disease
  266. microfossil
    a very tiny impression left by an organism from a past geological age
  267. Mid-Atlantic Ridge
    a very long narrow elevation on the ocean floor that runs all the way from Iceland in the North Atlantic to Bouvet Island in the South Atlantic
  268. mine
    get from the earth by excavation
  269. mineral
    a solid inorganic substance occurring in nature
  270. mineralogist
    a scientist trained in mineralogy
  271. mining
    the act of extracting ores or coal from the earth
  272. mitigation
    the action of lessening in severity or intensity
  273. Mohs scale
    a scale of hardness of solids
  274. molten
    reduced to liquid form by heating
  275. monsoon
    rainy season in southern Asia
  276. mountain
    a land mass that projects well above its surroundings
  277. mountain chain
    a series of hills or mountains
  278. mountain range
    a series of hills or mountains
  279. mudslide
    a rapid downward flow of soft, wet earth from a slope
  280. natural resource
    material in the environment that can be used by people
  281. neap tide
    a less than average tide occurring at the first and third quarters of the moon
  282. niche
    status or place of an organism within its environment
  283. nitrogen fixation
    the assimilation of atmospheric nitrogen by soil bacteria and its release for plant use on the death of the bacteria
  284. normal fault
    an inclined fault in which the hanging wall appears to have slipped downward relative to the footwall
  285. nuclear energy
    the energy released by a nuclear reaction
  286. nuclear fission
    a nuclear reaction in which a massive nucleus splits into smaller nuclei with the simultaneous release of energy
  287. nuclear fusion
    a nuclear reaction in which nuclei combine to form more massive nuclei with the simultaneous release of energy
  288. obsidian
    glass formed by the cooling of lava without crystallization
  289. occluded front
    (meteorology) a composite front when colder air surrounds a mass of warm air and forces it aloft
  290. ocean
    a large body of water that is part of the hydrosphere
  291. ocean current
    the steady flow of surface ocean water in a prevailing direction
  292. ocean floor
    the bottom of a sea or ocean
  293. oceanography
    the branch of science dealing with physical and biological aspects of the oceans
  294. oil shale
    shale from which oil can be obtained by heating
  295. ore
    a mineral that contains metal valuable enough to be mined
  296. organic
    having properties characteristic of living beings
  297. organism
    a living thing that can act or function independently
  298. oxygen
    a colorless, odorless gas that is essential for respiration
  299. ozone
    a colorless gas that is a screen for ultraviolet radiation
  300. ozone layer
    a region of the stratosphere that blocks UV radiation from the sun
  301. Pacific Ocean
    the largest ocean in the world
  302. paleontology
    the earth science that studies fossil organisms
  303. Paleozoic
    relating to the era from about 541 to 252 million years ago
  304. Pangaea
    (plate tectonics) a hypothetical continent including all the landmass of the earth prior to the Triassic period when it split into Laurasia and Gondwanaland
  305. particle
    (nontechnical usage) a tiny piece of anything
  306. particulate
    a small discrete mass of solid or liquid matter that remains individually dispersed in gas or liquid emissions (usually considered to be an atmospheric pollutant)
  307. pelagic
    relating to, occurring in, or living in the open ocean
  308. percolation
    the slow passage of a liquid through a filtering medium
  309. period
    a unit of geological time when a system of rocks formed
  310. permeable
    allowing fluids or gases to pass or diffuse through
  311. pesticide
    a chemical used to kill destructive insects or animals
  312. petrifaction
    the process of turning some plant material into stone
  313. petrochemical
    any compound obtained from petroleum or natural gas
  314. petroleum
    a dark oil consisting mainly of hydrocarbons
  315. pH
    a measure of the acidity or alkalinity of a solution
  316. Phanerozoic
    relating to the eon from about 541 million years ago to the present
  317. photic
    of or relating to or caused by light
  318. photosynthesis
    formation of compounds in plants aided by radiant energy
  319. photovoltaic cell
    a cell that converts solar energy into electrical energy
  320. plate
    a rigid layer of the Earth's crust
  321. plateau
    a relatively flat raised area of land
  322. plate tectonics
    the movement or study of the movement of Earth's crust
  323. pluton
    large mass of intrusive igneous rock believed to have solidified deep within the earth
  324. polar
    located at or coming from the earth's extremities
  325. pole
    either of the two endpoints of the Earth's axis of rotation
  326. pollutant
    waste matter that contaminates the water, air, or soil
  327. pollution
    contamination of the natural environment
  328. population
    a group of organisms of the same species inhabiting an area
  329. population growth
    increase in the number of people who inhabit a territory or state
  330. porphyritic
    (of rocks) consisting of porphyry or containing large crystals in a fine groundmass of minerals
  331. potable
    suitable for drinking
  332. Precambrian
    the vast span of time from about 4.6 billion to 541 million years ago
  333. precipitation
    the falling to earth of any form of water
  334. prehistoric
    belonging to or existing before recorded times
  335. preserve
    a region where animals are protected
  336. pressure
    the force exerted by the atmosphere
  337. process
    a sustained phenomenon through a series of states
  338. psychrometer
    a hygrometer consisting of a dry-bulb thermometer and a wet-bulb thermometer; their difference indicates the dryness of the surrounding air
  339. pumice
    a porous rock formed on the surface of some lavas
  340. radiation
    energy transmitted in the form of rays or waves or particles
  341. radiocarbon dating
    an analysis used to determine the age of organic materials
  342. radioisotope
    a radioactive isotope of an element
  343. rainfall
    water falling in drops from vapor condensed in the atmosphere
  344. rain forest
    a forest with heavy annual rainfall
  345. rain gauge
    gauge consisting of an instrument to measure the quantity of precipitation
  346. rain shadow
    an area that has little precipitation because some barrier causes the winds to lose their moisture before reaching it
  347. recharge
    charge anew
  348. reclamation
    the conversion of wasteland into land suitable for use
  349. recycle
    use again after processing
  350. reforestation
    the restoration (replanting) of a forest that had been reduced by fire or cutting
  351. relative humidity
    the ratio of the amount of water in the air at a given temperature to the maximum amount it could hold at that temperature; expressed as a percentage
  352. renewable
    capable of being replaced
  353. renewable resource
    any natural resource (as wood or solar energy) that can be replenished naturally with the passage of time
  354. reservoir
    lake used to store water for community use
  355. resource
    a new or reserve supply that can be drawn upon when needed
  356. reverse fault
    a geological fault in which the upper side appears to have been pushed upward by compression
  357. Richter scale
    a system once used to measure the strength of an earthquake
  358. ridge
    a long narrow natural elevation or striation
  359. rift valley
    a valley with steep sides
  360. river
    a large natural stream of water (larger than a creek)
  361. rock
    material consisting of the aggregate of minerals
  362. runoff
    the occurrence of surplus liquid exceeding capacity
  363. salinity
    the relative proportion of salt in a solution
  364. sand
    a loose material consisting of grains of rock or coral
  365. sandstorm
    a windstorm that lifts up clouds of dust or sand
  366. savanna
    a flat grassland in tropical or subtropical regions
  367. sea breeze
    a cooling breeze from the sea (during the daytime)
  368. sea level
    level of the ocean's surface
  369. seamount
    an underwater mountain rising above the ocean floor
  370. season
    one of the natural periods into which the year is divided by the equinoxes and solstices or atmospheric conditions
  371. seasonal
    occurring at or dependent on a particular season
  372. sediment
    matter that has been deposited by some natural process
  373. sedimentary
    formed by or containing the accumulation of deposited matter
  374. sedimentary rock
    rock formed from consolidated clay deposits
  375. sedimentation
    the accumulation of matter deposited by some natural process
  376. seepage
    the slow escape of liquid or gas through small holes
  377. seismic
    subject to or caused by an earthquake or earth vibration
  378. seismograph
    an instrument for measuring movements of the ground
  379. seismography
    the measurement of tremors and shocks and undulatory movements of earthquakes
  380. seismologist
    a scientist who studies earthquakes
  381. semiprecious
    used of gemstones having less commercial value than precious stones
  382. sequestration
    the action of forming a chelate or other stable compound with an ion or atom or molecule so that it is no longer available for reactions
  383. shale
    a sedimentary rock formed by the deposition of successive layers of clay
  384. shear
    a deformation of an object in which parallel planes shift
  385. sill
    (geology) a flat (usually horizontal) mass of igneous rock between two layers of older sedimentary rock
  386. silt
    mud or clay or small rocks deposited by a river or lake
  387. sinkhole
    a depression in the ground communicating with a subterranean passage and formed by solution or by collapse of a cavern roof
  388. sleet
    precipitation consisting of a mixture of rain and snow
  389. smelt
    extract by heating, as a metal
  390. smog
    air pollution by a mixture of smoke and fog
  391. soil
    material in the top layer of the surface of the earth
  392. solar
    relating to the sun or utilizing the energies of the sun
  393. solar power
    energy from the sun that is converted into thermal or electrical energy
  394. solar radiation
    radiation from the sun
  395. sonar
    a method of finding objects under water using sound waves
  396. species
    taxonomic group whose members can interbreed
  397. specific gravity
    the density of a substance relative to the density of water
  398. spring
    a natural flow of ground water
  399. stalactite
    a cylinder of calcium carbonate hanging from a cave roof
  400. stalagmite
    a cylinder of calcium carbonate projecting from a cave floor
  401. stratosphere
    atmospheric layer between the troposphere and the mesosphere
  402. stratum
    one of several parallel layers of material
  403. stratus
    a large dark low cloud
  404. stress
    (physics) force that produces strain on a physical body
  405. strike-slip fault
    a geological fault in which one of the adjacent surfaces appears to have moved horizontally
  406. subduction
    movement of the edge of one tectonic plate under another
  407. sublimation
    a change directly from the solid to the gaseous state
  408. subsidence
    a gradual sinking to a lower level
  409. subtropical
    of or relating to or characteristic of conditions in the subtropics
  410. succession
    the gradual and orderly process of change in an ecosystem
  411. superposition
    (geology) the principle that in a series of stratified sedimentary rocks the lowest stratum is the oldest
  412. surface
    the outermost level of the land or sea
  413. surface mine
    extract (ore) from a strip-mine
  414. sustainability
    the capacity of being prolonged
  415. swell
    a rounded elevation (especially one on an ocean floor)
  416. system
    a group of independent elements comprising a unified whole
  417. technology
    the practical application of science to commerce or industry
  418. tectonic
    pertaining to the structure or movement of the earth's crust
  419. temperate
    mild or free from extremes
  420. temperature
    the degree of hotness or coldness of a body or environment
  421. temperature gradient
    change in temperature as a function of distance
  422. tension
    a stress that produces an elongation of a physical body
  423. texture
    the physical composition of something
  424. thermal
    relating to or associated with heat
  425. thermometer
    measuring instrument for measuring temperature
  426. thermosphere
    the atmospheric layer between the mesosphere and the exosphere
  427. thunderstorm
    a storm resulting from strong rising air currents
  428. tide
    the periodic rise and fall of the sea level
  429. tilt
    property possessed by a line that departs from the vertical
  430. time scale
    an arrangement of events used as a measure of duration
  431. topsoil
    the layer of soil on the surface
  432. tornado
    a violently destructive windstorm occurring over land
  433. tourmaline
    a mineral that is a complex borosilicate and hydroxide of aluminum containing iron and magnesium and calcium and lithium and sodium; it is usually black but occurs in transparent colored forms that are used as gemstones
  434. trade wind
    steady winds blowing from east to west above and below the equator
  435. trench
    a long steep-sided depression in the ocean floor
  436. Triassic
    the geologic period from about 252 to 201 million years ago
  437. tropical
    relating to part of the Earth's surface with hot climate
  438. tropical rain forest
    a rain forest in a tropical area
  439. troposphere
    the lowest atmospheric layer; from 4 to 11 miles high
  440. trough
    a narrow depression, as between waves
  441. tsunami
    a cataclysm resulting from a destructive sea wave
  442. tundra
    a vast treeless plain where subsoil is permanently frozen
  443. turbid
    clouded as with sediment
  444. turbine
    an engine that causes a bladed rotor to rotate
  445. typhoon
    a tropical cyclone in the western Pacific or Indian oceans
  446. undertow
    a current that flows away from the shore after waves break
  447. uplift
    lift up from the earth, as by geologic forces
  448. uranium
    a heavy, silvery-white, radioactive, metallic element
  449. urbanization
    the social process whereby cities grow
  450. vapor
    a visible suspension in the air of particles of a substance
  451. vegetation
    all the plant life in a particular region or period
  452. vein
    a layer of ore between layers of rock
  453. volcanic
    relating to eruptions of gas and lava from the earth's crust
  454. volcanic glass
    a kind of natural glass produced when molten lava cools very rapidly
  455. volcanism
    the phenomena associated with volcanic activity
  456. volcano
    a fissure in the earth's crust through which gases erupt
  457. warm front
    the front of an advancing mass of warmer air
  458. waste
    any materials unused and rejected as worthless or unwanted
  459. water pollution
    pollution of the water in rivers and lakes
  460. watershed
    the geographical area drained by a river and its tributaries
  461. water table
    underground surface below which the ground is fully saturated with moisture
  462. water vapor
    water in a vaporous form diffused in the atmosphere but below boiling temperature
  463. wave
    a ridge that moves across the surface of a liquid
  464. wavelength
    distance between successive crests of a periodic disturbance
  465. weather
    atmospheric conditions such as temperature and precipitation
  466. weather map
    (meteorology) a map showing the principal meteorological elements at a given time and over an extended region
  467. westerly
    the winds from the west that occur in the temperate zones of the Earth
  468. wetland
    an ecosystem, like a bog or swamp, saturated with water
  469. whitecap
    a wave that is blown by the wind so its crest is broken and appears white
  470. wildfire
    a destructive burning that is raging and rapidly spreading
  471. wind
    air moving from high pressure to low pressure
  472. wind farm
    a power plant that uses wind turbines to generate electricity
  473. wind power
    power derived from the wind (as by windmills)
  474. wind turbine
    a turbine that is driven by the wind
  475. wind vane
    mechanical device attached to an elevated structure
Created on Wed Feb 15 21:03:16 EST 2017 (updated Fri Apr 21 14:24:15 EDT 2017)

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