NYSTCE Earth Science (162) key terms

An iterative process of observing, asking questions, forming testable hypotheses, collecting data through controlled investigations, and revising explanations based on evidence rather than opinion or authority.

A tentative, testable statement that predicts an outcome and can be supported or rejected by evidence gathered during an investigation.

An investigation in which all variables except the one being tested are held constant, allowing a fair comparison between experimental and control groups.

The factor deliberately changed or manipulated by the investigator in an experiment; it is plotted on the horizontal axis of a graph.

The factor that is measured or observed in response to changes in another variable; it is plotted on the vertical axis of a graph.

The comparison group in an experiment that does not receive the treatment being tested, providing a baseline against which results are judged.

A quality-control process in which independent experts evaluate the methods, evidence, and reasoning of a study before publication, helping screen out flawed or unsupported claims.

A broad, well-tested explanation for a body of observations that is supported by extensive evidence and has survived repeated attempts at falsification; not a mere guess.

A concise statement, often mathematical, describing a consistent regularity observed in nature, such as Newton's law of universal gravitation.

The mass of a substance per unit volume, usually expressed in grams per cubic centimeter; it explains floating, sinking, and layering of Earth materials.

The range within which a measured value is expected to lie, arising from limitations of instruments and technique; reported with significant figures and error estimates.

The prevailing cosmological model stating the universe expanded from an extremely hot, dense state roughly 13.8 billion years ago and has been cooling and expanding since.

The stretching of light from distant galaxies toward longer wavelengths, interpreted as evidence that galaxies are receding and that the universe is expanding.

The observation that a galaxy's recession velocity is proportional to its distance from Earth, with the constant of proportionality called the Hubble constant.

Faint, nearly uniform microwave radiation filling the sky, interpreted as relic heat from the early universe shortly after the Big Bang.

The model in which a rotating cloud of gas and dust collapsed under gravity, flattened into a disk, and formed the Sun and planets about 4.6 billion years ago.

The process by which particles of gas and dust in the early solar nebula collided and stuck together, gradually building larger bodies called planetesimals and eventually planets.

A small, solid body formed early in solar system history by the clumping of dust and ice, which can collide and merge to form protoplanets.

Three rules describing planetary motion: orbits are ellipses with the Sun at one focus; equal areas are swept in equal times; and orbital period squared is proportional to semi-major axis cubed.

The attractive force between masses that governs the orbits of planets, moons, and satellites, and drives accretion, tides, and the formation of stars.

The curved path of one body around another, maintained by the balance between forward motion and gravitational attraction.

The Sun and all bodies gravitationally bound to it, including eight planets, dwarf planets, moons, asteroids, comets, and dust.

A small, dense, rocky planet with a solid surface and metallic core, such as Mercury, Venus, Earth, and Mars.

A large, low-density planet composed mainly of hydrogen, helium, and ices, with no solid surface; includes Jupiter, Saturn, Uranus, and Neptune.

The periodic rise and fall of sea level caused mainly by the gravitational pull of the Moon and Sun on Earth's oceans, producing two high and two low tides daily.

An event in which one celestial body passes into the shadow of another or blocks its light, occurring when the Sun, Earth, and Moon align.

The changing appearance of the Moon caused by the varying portion of its sunlit half visible from Earth as it orbits through a monthly cycle.

The unifying theory that Earth's rigid lithosphere is broken into plates that move over the asthenosphere, causing earthquakes, volcanoes, and mountain building.

Transfer of heat by the circulation of a fluid in which warm, less dense material rises and cooler, denser material sinks; drives mantle flow and plate motion.

The process by which new oceanic crust forms at mid-ocean ridges as magma rises and solidifies, then moves away from the ridge on both sides.

A boundary where one denser tectonic plate descends beneath another, generating deep earthquakes, volcanic arcs, and ocean trenches.

The ongoing series of processes by which igneous, sedimentary, and metamorphic rocks transform into one another through melting, cooling, weathering, erosion, deposition, and heat and pressure.

Rock formed when molten magma or lava cools and solidifies; intrusive types cool slowly with large crystals, while extrusive types cool quickly with fine crystals.

Rock formed from compacted and cemented sediments or from chemical precipitation, commonly layered and the main archive of fossils.

Rock altered in the solid state by high heat and pressure, often developing foliation or recrystallized minerals without melting.

The breakdown of rock at or near Earth's surface by physical, chemical, or biological processes, producing sediment without transporting it.

The removal and transport of weathered material by agents such as water, wind, ice, or gravity, shaping landforms and depositing sediment elsewhere.

The laying down of eroded sediment when the transporting agent loses energy, forming layers that may later become sedimentary rock.

The state of gravitational balance in which lighter crustal material floats on denser mantle material, adjusting as weight is added or removed.

Preserved remains or traces of ancient organisms, usually found in sedimentary rock, used to reconstruct past life and environments.

Determining the order of past events without assigning numerical ages, using principles such as superposition, original horizontality, and cross-cutting relationships.

The principle that in an undisturbed sequence of sedimentary rock layers, each layer is older than the one above it and younger than the one below.

Estimating the numerical age of a rock or mineral by measuring the ratio of a radioactive parent isotope to its stable daughter product and applying the known half-life.

The time required for half of the atoms of a radioactive isotope in a sample to decay into daughter products; each isotope has a fixed, characteristic value.

A fossil of an organism that existed for a short time but was widely distributed geographically, allowing correlation of rock layers across regions.

The chronological framework dividing Earth history into eons, eras, periods, and epochs, based largely on changes in fossils and major geologic or biological events.

A geologically rapid event in which a large proportion of species disappears, often linked to asteroid impacts, volcanism, or climate change, and used to mark boundaries on the time scale.

The principle that the same natural processes operating today, such as erosion and deposition, also operated in the past and can explain ancient rock formations.