Earth Science Vocabulary
Group 1
Lithosphere- rigid outer shell of Earth including the crust and solid uppermost part of the mantle
Metamorphic rocks-form from changes in temperature and pressure; examples are slate and marble
Igneous rocks- crystallize from magma; examples are obsidian and basalt
Sedimentary rocks- form from cemented sediments; examples are sandstone and shale
Erosion- movement of weathered materials from one location to another
Exfoliation- a type of mechanical weathering; when outer layers of rock are stripped away over time
Deposition- final stage of erosion process when sediments are laid down on the ground or settle to the
bottom of a body of water
Foliation- process of minerals aligning in bands due to pressure; found in metamorphic rocks
Weathering- chemical or mechanical process that breaks down and changes rocks on or near Earth’s surface;
influenced by precipitation and temperature
Mass movement- movement of loose sediments and weathered rock due to the force of gravity
Group 2
Oxidation- chemical reaction of oxygen with other substances
Convergent boundary- where two tectonic plates are moving toward each other; form trenches, island arcs,
folded mountains; destroy Earth’s crust
Divergent boundary- where two tectonic plates are moving away from each other; form volcanoes,
earthquakes, high heat flow; create Earth’s crust
Transform boundary- where two tectonic plates slide horizontally past each other; form long faults, shallow
earthquakes; conserve Earth’s crust
Rift valley- long narrow depression that forms when the crust separates at a divergent boundary
Subduction zone- place where one tectonic plate slides beneath another; slab pull
Mantle convection- transfer of thermal energy by movement of heated matter
Group 3
Renewable resource- can be used indefinitely without causing a reduction in available supply; examples are
air, groundwater
Non-renewable resource- exists in a fixed amount and can only be replaced by geological, physical or chemical
processes that take 100s of millions of years; examples are coal, diamonds
Urbanization- process of rapid development of areas previously more rural
Mining- process of removing coal or other minerals or resources from a mine
Monadnock- isolated rock hill or small mountain that rises from a relatively level surrounding area
Deforestation- removal of trees from a forested area without adequate replanting, often using clear-cutting
which may result in loss of topsoil and water pollution
Fall line- break between an upland region of hard rock and a coastal region of softer rock; characterized by
waterfalls and rapids
Group 4
Solution- when material has dissolved in a stream’s water
Abrasion- particles that rub and scrape against one another as they tumble
Flood plain- low-lying area of land that is submerged during floods
Lakes- depression in the surface of a landscape that collects and holds water
Stream load- all the materials that the water in a stream carries; has both living and non-living components
Wetland- land area covered with water for most of the year
Watershed- all of the land area whose water drains into a stream system
Eutrophication- process by which lakes become rich in nutrients which results in a change of organisms in the
lake
Bed load- sediments too large to be held up by turbulent water; these sediments are pushed and rolled along
the stream bed
Suspension- materials small enough to be held up by turbulence of a stream’s moving water
Group 5
Stalagmite- form from drips of water that deposit tiny amounts of calcium carbonate; form on cave floors
Stalactite- form from drips of water that deposit tiny amounts of calcium carbonate; form on cave ceilings
Zone of Saturation- depth below Earth’s surface at which groundwater completely fills all the pores of a
material
Permeability- ability of a material to let water pass through it; highest in materials with large, well-connected
pores
Aquifer- permeable layers in the Earth that allow groundwater to flow through it
Infiltration- process where precipitation that falls on land enters into the ground
Porosity- percentage of pore space in a material; highest in well sorted material
Travertine- type of limestone that produces dripstone formations
Karst topography- limestone regions that have sinkholes, sinks and sinking streams
Group 6
Recharge- when water from precipitation and runoff is added back to the zone of saturation
Subsidence- when land over an aquifer sinks due to a decrease of water
Radon- naturally occurring radioactive gas that forms from decaying uranium; leading cause of cancer in the
United States; found in small amounts in all groundwater
Geyser- explosive hot spring; Old Faithful is an example
Spring- natural discharge of groundwater; classified by temperature; ex. hot springs have temperatures
greater than human body temperature
Artesian well- fountain that forms from a confined aquifer
Drawdown-difference between the original water table level and the water level in a pumped well
Group 7
Brackish- slightly salty; where freshwater meets salt water
Habitat- area that supports animal and plant species
Point source- water pollution that comes from a single point of origin that is easily traced to a source; oil spill
Non-point source- water pollution that generally creates pollution from wide-spread areas; runoff from roads
Estuary- coastal area of brackish water
River basin- land drained by a river and its tributaries
Group 8
Ozone (O3)- formed by adding an extra oxygen atom to an oxygen molecule; absorbs ultraviolet (UV) radiation
from the Sun
Troposphere- lower atmospheric layer closest to the Earth’s surface; contains most of the atmosphere’s mass;
where most weather events occur; gets colder as you go higher; 9km (at the poles) to 16km (at the tropics)
above the Earth’s surface
Stratosphere- lower atmospheric layer that is mostly made of ozone; gets warmer as you get higher because
the ozone absorbs UV radiation; up to 50km above the Earth’s surface
Mesosphere- upper atmospheric layer; gets colder as you go higher; up to 100km above Earth’s surface
Thermosphere- upper atmospheric layer; gets warmer as you go higher (to over 1000 oC); contains only a small
part of the atmosphere’s mass; the ionosphere (layer of electrically charged particles) is found here; up to
500km above Earth’s surface
Exosphere- outer most layer of Earth’s atmosphere; up to 700km above Earth’s surface
Radiation- transfer of energy from the Sun through space by visible light, UV radiation and other forms of
electromagnetic waves
Convection- transfer of energy by the flow of a heated substance; convection currents
Conduction- transfer of energy that occurs when molecules collide; substances must be in contact
Group 9
Relative humidity- ratio of water vapor in a volume of air relative to how much water vapor the volume of air
can actually hold at a given temperature; warm air can hold more water vapor than cold air; expressed as a
percent
Temperature inversion- when an increase in temperature occurs with an increase in height in the atmosphere
Lifted condensation level (LCL)- height at which condensation occurs in the atmosphere; occurs at the base of
clouds
Dew point- temperature to which air must be cooled at a constant pressure to reach saturation
Group 10
Latent heat- heat stored in water vapor that is released when condensation occurs
Orographic lifting- method of cloud formation; occurs when wind hits a mountainside and flows upward,
expands and then cools
Condensation nuclei- small particles in the atmosphere around which droplet can form; sea salt and dust
Coalescence- occurs when cloud droplets collide to form a larger droplet; droplets will fall as precipitation
once they get large enough for gravity to have an effect
Group 11
Pressure gradient – difference in pressure over a given distance
Coriolis effect – movement of an object (wind) due to Earth’s rotation
Jet stream – fast moving rivers of air; move WEST to EAST at 120 to 240 km/hr
Front – region that separates two air masses of different densities; 4 types – cold, warm, stationary, occluded
High pressure system – air falls and spreads out from the center; move clockwise in the N. hemisphere;
usually associated with good weather
Low pressure system – air rises and moves toward the center; move counter-clockwise in the N. hemisphere;
usually associated with clouds and precipitation
Group 12
Barometer – device that measures air pressure
Anemometer – device that measures wind speed
Hygrometer – device that measures relative humidity
Analog forecast – type of forecast that compares current weather patterns to weather patterns that took
place int the past
Isopleth – lines that connect points of equal or constant values
Digital forecast – forecast that relies on numerical data
Ceilometer – device that measures the height of clouds and estimates the percentage of cloud cover
Doppler effect – change in wave frequency that occurs in energy (light or sound) as the energy moves towards
or away from the observer
Meteorology – study of atmospheric phenomena
Thermometer – device that measures temperature
Radiosonde – package of sensors lifted into the upper layers of the atmosphere by balloons
Group 13
Climatology – study of Earth’s climate
Tropics – area between 23.5o N & S from the equator; receives mostly direct sunlight; warm most of the year
Temperate zone – between 23.5o and 66.5o N & S of the equator; receives more oblique sunlight; moderate
temperatures year round
Polar zone – area from 66.5o N & S to the poles; receives a low amount of sunlight; cold temperatures year
round
Greenhouse effect – retention of heat by Earth’s atmosphere; most common greenhouse gas is carbon
dioxide
Koeppen classification system – system that uses average monthly rainfall and temperatures and types of
distinct vegetation to classify climates
Microclimate – a localized climate that differs from the main regional climate; ex. Top of a mountain
Heat island – caused by large areas of concrete and asphalt that radiate large amounts of heat compared to
surrounding grassy areas
Maunder minimum – period of very low sunspot activity; coincides with much colder weather
El Niño – warm ocean current that develops off the western South American coast; can cause storms in dry
areas and drought in wet areas
Group 14
Biodiversity – degree of variation of life; can be genetic, species, ecosystem
Abiotic – non-living chemical and physical factors in the environment that affect ecosystems; ex. Soil, water,
air, temperature, sunlight
Biotic – living or once living component of an ecosystem; comprised of producers (plants), consumers
(animals) and decomposers (fungi, bacteria)
Biosphere – all life on Earth; ex. Plants, animals, bacteria, etc.
Group 15
Perigee – closest point to the Earth in the Moon’s orbit
Apogee – farthest point from the Earth in the Moon’s orbit
Mare (maria-plural) – dark, smooth plains on the lunar surface
Interferometry – process of linking separate telescopes together so that they act as one telescope; image
detail improves with greater distance
Albedo – amount of light reflected by the lunar surface
Regolith – layer of loose, ground-up rock
Synchronous rotation – state where the Moon’s orbital and rotational periods are equal
Refracting telescope – telescopes that use lenses to focus light
Reflecting telescope – telescopes that use mirrors to focus light
Ejecta – material blasted out during a surface impact that falls back to the lunar surface
Group 16
Geocentric model – early theory that the Sun, Moon, planets and starts revolve around the Earth
Barycenter – center of mass between two or more celestial bodies that orbit each other
Aphelion – when a planet is farthest in its orbit from the Sun
Perihelion – when a planet is closest in its orbit to the Sun
Heliocentric model – theory that the Earth, Moon and planets revolve around the Sun
Nebula – a cloud of gas
Precession – the wobble in Earth’s rotational axis caused by gravitational pull from the Moon and the Sun
Retrograde motion – when a planet appears to move in the opposite direction (East to West)
Nutation – swaying or nodding motion in the axis of rotation
Group 17
Chromosphere – can be seen during an eclipse; red in color; about 2500km thick; temp = 30,000K
Corona – forms the solar wind; several million km thick; temp between 1 and 2 million K
Photosphere – lowest layer of the Sun’s atmosphere; most light is emitted from this layer; about 400km thick;
temp = 5800K
Prominence – arc of gas ejected from the chromosphere
Fusion – combining of light atomic nuclei into heavier ones; hydrogen into helium; uses massive amounts of
energy
Fission – splitting of heavy atomic nuclei into lighter ones; helium into hydrogen; gives off massive amounts of
energy