OAE Earth and Space Science key terms

A testable, tentative explanation for an observed pattern that generates predictions able to be checked against evidence. It must be falsifiable, meaning some conceivable observation could show it to be wrong.

A broad, well-supported explanation built from many tested hypotheses and lines of evidence, such as plate tectonics. In science the word does not mean a guess or an unproven idea.

Data gathered through observation, measurement, or experiment rather than from authority or intuition. Scientific claims are accepted or rejected based on how well such evidence supports their predictions.

Evaluation of a study's methods, data, and reasoning by independent experts before publication. It screens for errors and weak claims, though it does not guarantee that results are correct.

The principle that the same physical and chemical processes observed today, operating over long spans of time, can explain features preserved in the rock record. It grounds interpretations of Earth history.

The theory that Earth's rigid outer shell is broken into plates that move over a weaker layer, causing earthquakes, volcanoes, mountain building, and ocean-basin formation at their boundaries.

Vibrational energy released by an earthquake or explosion that travels through Earth. P waves compress rock and pass through fluids; S waves shear rock and cannot travel through liquids.

The crust, mantle, and core, distinguished by composition and by physical state. The liquid outer core generates the magnetic field; the solid inner core lies at the center.

Slow circulation of hot rock in the mantle driven by heat from the core and by cooling near the surface. It is a principal driver of plate motion and of volcanic activity above rising plumes.

A plate margin where two plates move apart and new lithosphere forms from upwelling magma. Examples include mid-ocean ridges, where seafloor spreading creates new ocean crust.

A convergent margin where one lithospheric plate descends beneath another. It produces deep ocean trenches, volcanic arcs, and the deepest and largest earthquakes.

The process by which new oceanic crust forms at mid-ocean ridges and moves away on both sides. Magnetic stripes and age patterns in the crust record this motion.

The point inside Earth where rock ruptures and seismic energy is released. Its surface projection is the epicenter, and depth to the focus affects shaking at the surface.

The set of processes that transform igneous, sedimentary, and metamorphic rock into one another through melting, cooling, weathering, erosion, deposition, burial, and metamorphism over geologic time.

The breakdown of rock in place by physical, chemical, or biological processes. It produces sediment and soil but does not itself transport material away from its source.

The removal and transport of weathered material by water, wind, ice, or gravity. It shapes landforms and, together with deposition, redistributes sediment across landscapes.

The laying down of sediment when the transporting agent loses energy, as when a river slows at its mouth or wind speed drops. Deposited layers may later become sedimentary rock.

Determining the order of geologic events without assigning numerical ages, using principles such as superposition and cross-cutting relationships. It establishes sequences, not absolute dates.

A feature produced by moving ice or its meltwater, such as a U-shaped valley, moraine, drumlin, or erratic boulder. Such features indicate past ice extent and flow direction.

Warming of a planet's surface because gases absorb outgoing infrared radiation and re-emit it downward. Water vapor, carbon dioxide, and methane are major contributors in Earth's atmosphere.

The fraction of incoming solar radiation reflected by a surface. Ice and snow have high albedo; ocean and dark land have low albedo, so surface changes can alter how much energy Earth absorbs.

A process triggered by a change that either amplifies it (positive feedback) or dampens it (negative feedback). Ice-albedo loss is a positive feedback; increased cloud cover can act as a negative one.

The apparent deflection of moving air or water caused by Earth's rotation. It deflects motion to the right in the Northern Hemisphere and to the left in the Southern Hemisphere.

A large body of air with relatively uniform temperature and humidity acquired over a source region. Boundaries between air masses, called fronts, are where much weather develops.

The upper boundary of the saturated zone in the ground, below which pore spaces are filled with water. It rises and falls with recharge from precipitation and discharge to wells and streams.

A body of rock or sediment that stores and transmits groundwater in usable quantities. Its productivity depends on porosity and permeability, and it can be confined or unconfined.

The land area draining to a common outlet such as a river mouth or lake. Its boundaries follow topographic divides, and its size and land use affect downstream water quantity and quality.

The portion of Earth's system that is frozen, including glaciers, ice sheets, sea ice, permafrost, and snow. Its changes affect sea level, albedo, and freshwater supply.

Long-term variations in Earth's orbit and axial tilt, including eccentricity, obliquity, and precession. They change the seasonal distribution of solar energy and pace glacial-interglacial cycles.

A recurring change in solar heating caused mainly by Earth's axial tilt as it orbits the Sun. Hemisphere differences in daylight and solar angle drive seasonal weather and climate patterns.

The changing illuminated fraction of the Moon seen from Earth as it orbits, from new to full and back. Phases depend on the Sun-Moon-Earth geometry, not on Earth's shadow.

An event in which the Moon passes between Earth and the Sun and blocks some or all of the Sun's light. It occurs only near a new moon, when the alignment is close enough.

Three descriptions of orbital motion: orbits are ellipses with the Sun at one focus; a planet sweeps equal areas in equal times; and orbital period squared is proportional to semi-major axis cubed.

The sequence a star follows from nebular collapse through main-sequence fusion to a final state. Mass determines the path: low-mass stars become white dwarfs, while massive stars may end as neutron stars or black holes.

A plot of stellar luminosity against temperature or spectral class. It reveals the main sequence, giants, and white dwarfs, and helps explain how stars evolve and how distance is estimated.

A cloud of gas and dust in space. Some are star-forming regions where gravity causes collapse; others are remnants shed by dying stars and contribute material to future generations of stars.

Observations supporting an expanding universe from a hot, dense early state: cosmic microwave background radiation, the abundance of light elements, and the redshift-distance relation of galaxies.

Teaching in which students investigate questions, collect and analyze data, and construct evidence-based explanations. The teacher facilitates and scaffolds rather than simply presenting conclusions.

Ongoing checks of student understanding used to adjust instruction during learning. It contrasts with summative assessment, which judges achievement at the end of a unit.

A persistent, plausible but incorrect idea that students bring to science, such as believing seasons result from distance to the Sun. Effective instruction elicits and directly challenges such ideas.