CSET Earth & Space Sciences (219) flashcards

32 cards. Read the term and the definition here. The deck at the top of this page is optional.

Kepler's third law

The square of an orbital period equals the cube of the semi-major axis when period is in years and axis in astronomical units; applies to bodies orbiting the Sun.

Spectral class order

Stars are classified O, B, A, F, G, K, M from hottest to coolest; each class is subdivided 0 to 9, with 0 being hotter within a class.

Redshift

A shift of spectral lines toward longer wavelengths caused by a receding source; the fractional shift gives radial velocity when the speed is much less than light speed.

Nebular hypothesis

The model in which a rotating cloud of gas and dust collapses into a disk, forming the Sun at the center and planets by accretion of planetesimals.

Synodic month

The interval between successive identical lunar phases, about 29.5 days, longer than the 27.3-day sidereal month because Earth also orbits the Sun.

Absolute magnitude

A star's intrinsic brightness measured as it would appear from a standard distance of 10 parsecs; lower numbers indicate brighter stars.

S-wave shadow zone

The region where shear waves are not detected, from about 103 to 180 degrees from an earthquake; it reveals that the outer core is liquid.

Mohorovičić discontinuity

The boundary between Earth's crust and mantle, marked by an abrupt increase in seismic wave velocity due to denser mantle rock.

Bowen's reaction series

The order in which minerals crystallize from cooling magma, from olivine and calcium-rich plagioclase early to quartz and potassium feldspar late.

Felsic magma

Magma rich in silica and low in iron and magnesium; it is viscous and tends to produce explosive eruptions and lighter-colored rocks such as granite.

Transform boundary

A plate boundary where two plates slide past each other horizontally; earthquakes are common but volcanic activity is generally absent.

Mohs hardness scale

A relative scale from 1 (talc) to 10 (diamond) ranking minerals by scratch resistance; quartz is 7 and calcite is 3.

Rock cycle

The set of processes linking igneous, sedimentary, and metamorphic rocks through melting, cooling, weathering, erosion, deposition, compaction, and metamorphism.

Coriolis effect

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

Hadley cell

A circulation loop between the equator and about 30 degrees latitude; rising moist air at the equator produces rain, and sinking dry air creates deserts.

Relative humidity

The ratio of the actual water vapor pressure in air to the saturation vapor pressure at the same temperature, expressed as a percentage.

Dew point

The temperature to which air must cool at constant pressure for it to become saturated; cooling below it produces condensation and clouds.

Thermohaline circulation

Deep ocean circulation driven by differences in temperature and salinity, which control water density; it transports heat and nutrients around the globe.

Ozone layer

A concentration of ozone in the stratosphere that absorbs ultraviolet radiation, warming that layer and shielding life at Earth's surface.

Upwelling

The rise of cold, nutrient-rich deep water toward the surface, often caused by winds moving surface water offshore; it supports productive fisheries.

Law of superposition

In an undisturbed sequence of sedimentary rocks, each layer is older than the layer above it and younger than the layer below.

Angular unconformity

An erosion surface where tilted or folded layers are overlain by younger, approximately horizontal layers, indicating deformation followed by erosion and deposition.

Half-life

The time required for half the atoms of a radioactive parent isotope in a sample to decay into daughter atoms; it is constant for each isotope.

Carbon-14 dating

A radiometric method using carbon-14 decay to date organic remains younger than about 50,000 years; it is not useful for older rocks.

Index fossil

A fossil of a species that existed for a short geologic interval but was geographically widespread, allowing correlation of rock layers across regions.

End-Permian extinction

The largest mass extinction, about 252 million years ago, eliminating most marine species and many land species; it marks the Paleozoic–Mesozoic boundary.

Disciplinary core ideas

The key science content organized in standards such as ESS1, ESS2, and ESS3, covering Earth's place in the universe, Earth's systems, and human activity.

Crosscutting concepts

Broad ideas that connect science fields, including patterns, cause and effect, scale, systems, energy and matter, structure and function, and stability and change.

Science and engineering practices

The behaviors scientists and engineers use, such as asking questions, developing models, planning investigations, analyzing data, and arguing from evidence.

Three-dimensional learning

Instruction that integrates disciplinary core ideas, science and engineering practices, and crosscutting concepts rather than teaching facts in isolation.

Phenomenon-based instruction

Teaching that begins with an observable event or pattern and asks students to explain it using evidence, models, and scientific reasoning.

Seasons misconception

The incorrect belief that seasons are caused by Earth's changing distance from the Sun; in fact, axial tilt and changing sunlight angle cause them.