MTTC Earth/Space Science (020) key terms

The systematic process of asking questions, forming testable hypotheses, gathering and analyzing evidence, and revising explanations based on results. It emphasizes empirical data, replication, and open communication of findings.

A tentative, testable explanation for an observed phenomenon, stated so that it could be shown false by evidence. It guides investigation but is not yet a confirmed conclusion.

Information obtained through direct observation, measurement, or experiment rather than through reasoning alone or appeal to authority. Scientific claims must be supported by such data, which others can examine.

An investigation that manipulates one variable while holding all other conditions constant, so that any change in results can be attributed to the manipulated factor rather than to confounding influences.

The factor deliberately changed or selected by the investigator in an experiment. Its effect on the measured outcome is what the study is designed to reveal.

The measured outcome that responds to changes in the independent variable. It provides the data used to evaluate whether the hypothesis is supported.

The consistency of a measurement or investigation: repeated trials under the same conditions yield similar results. Reliable data reduce random error but do not by themselves guarantee that a method measures the intended quantity.

The extent to which an investigation or measurement actually assesses what it claims to assess, free of systematic bias. A valid study supports conclusions that genuinely follow from the evidence collected.

The range within which a measured value is expected to lie, arising from instrument limits, technique, and random variation. Reporting uncertainty communicates how much confidence a result warrants.

The digits in a reported measurement that carry meaningful information about its precision. Rules for counting and rounding them keep calculated results consistent with the precision of the input data.

A compact way of writing very large or very small numbers as a coefficient between 1 and 10 multiplied by a power of ten. It simplifies computation and clearly conveys the scale and precision of values.

A simplified representation, physical, mathematical, or conceptual, of a real system, used to explain observations and make predictions. Models are always approximations and are revised as evidence accumulates.

A broad, well-tested explanation for a body of observations, supported by extensive evidence and accepted by the scientific community. In science, theory does not mean guess or speculation.

A concise statement, often mathematical, describing a consistent regularity observed in nature, such as a relationship among measurable quantities. Laws describe patterns; they do not by themselves explain underlying mechanisms.

The process in which independent experts evaluate a study's methods, evidence, and reasoning before publication. It filters weak claims and supports the self-correcting nature of science.

The unifying theory that Earth's rigid outer shell is broken into plates that move over the weaker mantle, causing earthquakes, volcanic activity, mountain building, and the opening and closing of ocean basins.

A plate margin where two plates move toward each other, producing subduction, deep ocean trenches, volcanic arcs, or continental collision and mountain belts. It is a major site of earthquakes and volcanism.

A plate margin where two plates move apart, allowing magma to rise and form new crust. Examples include mid-ocean ridges, where seafloor spreading occurs, and continental rift zones.

A plate margin where two plates slide horizontally past each other, neither creating nor destroying crust. Faults such as the San Andreas accommodate the motion and generate frequent earthquakes.

A region where one lithospheric plate descends beneath another into the mantle. Subduction recycles oceanic crust, generates deep trenches and volcanic arcs, and produces powerful earthquakes.

The process at mid-ocean ridges in which magma rises, solidifies, and creates new oceanic crust that moves away from the ridge. Magnetic striping and age patterns of the seafloor support this process.

The record of Earth's past magnetic field preserved in rocks, especially magnetic reversals frozen into oceanic crust. It provided key evidence for seafloor spreading and continental drift.

The ongoing series of processes, including melting, cooling, weathering, erosion, deposition, burial, and metamorphism, that transform rock among igneous, sedimentary, and metamorphic types over geologic time.

Rock formed from the cooling and solidification of magma or lava. Slow cooling underground produces coarse-grained intrusive rock, while rapid surface cooling produces fine-grained extrusive rock.

Rock formed from compacted and cemented sediments or from precipitated minerals. Layering and fossils are common features, and sedimentary sequences record past environments and depositional history.

Rock changed in the solid state by heat, pressure, or chemically active fluids, often developing foliation or new minerals. The parent rock's texture and mineral content are altered without melting.

The breakdown of rock at or near Earth's surface by physical, chemical, or biological processes. Weathering produces sediment and soil but does not itself transport material.

The removal and transport of weathered material by agents such as water, wind, ice, and gravity. Together with deposition, erosion shapes landforms and drives the rock cycle.

The continuous movement of water among oceans, atmosphere, land, and living things through evaporation, transpiration, condensation, precipitation, runoff, and infiltration. Solar energy and gravity drive it.

The exchange of carbon among the atmosphere, oceans, biosphere, soils, and rocks through photosynthesis, respiration, decomposition, combustion, and weathering. It regulates atmospheric carbon dioxide over short and long timescales.

The warming of a planet's surface as atmospheric gases absorb and re-emit outgoing infrared radiation. It keeps Earth habitable, but increased greenhouse gas concentrations strengthen it and raise global temperatures.

The fraction of incoming solar radiation reflected by a surface. Ice and snow have high albedo, oceans and forests low albedo, so albedo changes can amplify or dampen climate change.

Three empirical laws describing planetary orbits: orbits are ellipses with the Sun at one focus; planets sweep equal areas in equal times; and the square of the orbital period is proportional to the cube of the semimajor axis.

A number describing how much an ellipse deviates from a circle, from 0 for a circle to near 1 for a highly elongated orbit. It measures orbital shape, not tilt.

The Sun and all bodies gravitationally bound to it, including eight planets, dwarf planets, moons, asteroids, comets, and dust. It formed about 4.6 billion years ago from a collapsing nebula.

The explanation that the solar system formed from a rotating cloud of gas and dust that flattened into a disk, with the Sun condensing at the center and planets accreting from disk material.

The gradual buildup of larger bodies from smaller particles through collisions and sticking, as in planet formation within a protoplanetary disk. Accretion also builds planets from planetesimals.

The production of elements inside stars through nuclear fusion, including hydrogen burning and heavier-element synthesis in massive stars and supernovae. It accounts for the origin of most elements heavier than helium.

The changing appearance of the Moon as seen from Earth, caused by the varying fraction of its sunlit side visible to us as it orbits Earth. A complete cycle takes about 29.5 days.

An event in which the Moon passes between Earth and the Sun and blocks all or part of the Sun's light from a region on Earth. It occurs only near a new moon, when the alignment is nearly exact.

The periodic rise and fall of ocean water caused mainly by the Moon's gravitational pull and, to a lesser extent, the Sun's, combined with Earth's rotation. Spring and neap tides reflect their alignment.

The full range of electromagnetic radiation, from radio waves through infrared, visible light, ultraviolet, X-rays, and gamma rays. Different wavelengths carry different information about celestial objects.

The study of how matter absorbs and emits electromagnetic radiation at characteristic wavelengths. Astronomers use spectral lines to identify composition, temperature, motion, and density of distant objects.

The shift in observed wavelength of waves when the source and observer move relative to each other. In astronomy, redshift and blueshift reveal the motion of stars and galaxies.

The prevailing cosmological model in which the universe expanded from an extremely hot, dense state roughly 13.8 billion years ago. Cosmic expansion, the cosmic microwave background, and light-element abundances support it.

Ongoing, low-stakes evaluation during instruction that reveals what students understand so the teacher can adjust teaching and provide feedback. Its purpose is learning, not grading.

Evaluation conducted at the end of a unit or course to measure achievement against learning goals, such as a final exam or project. Results are typically reported as grades or proficiency levels.

A persistent, intuitive belief that conflicts with scientific understanding, such as the idea that seasons result from Earth's distance from the Sun. Effective instruction explicitly elicits and confronts these ideas.

The process by which learners reorganize their existing ideas into more accurate scientific frameworks, rather than simply adding facts. It typically requires confronting conflicting evidence and applying new ideas.

Teaching in which students investigate questions through their own observations, data collection, and reasoning, with the teacher guiding rather than dictating. It develops scientific practices alongside content knowledge.

A scoring guide that lists criteria and describes levels of performance, making evaluation of complex work such as investigations or models consistent and transparent to students.

Established procedures for conducting laboratory and field activities that prevent injury and exposure, including hazard identification, proper handling of materials, and emergency response. Teachers must plan and enforce these.