NY Regents Earth Science flashcards

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

Density

Mass per unit volume, calculated as mass divided by volume. It determines whether an object floats or sinks in a fluid and changes with temperature.

Specific heat

The amount of heat energy needed to raise one gram of a substance by one degree Celsius. Water's high specific heat moderates Earth's climate.

Convection

Heat transfer by the circulation of a fluid in which warmer, less dense material rises and cooler, denser material sinks, as in the mantle and atmosphere.

Dynamic equilibrium

A condition in which opposing forces or processes are balanced, so a system stays stable until an outside disturbance shifts the balance.

Lithosphere

The rigid outer layer of Earth made of the crust and uppermost mantle. It is broken into plates that move over the plastic asthenosphere.

Asthenosphere

The partially molten, plastic layer of the upper mantle beneath the lithosphere. It flows slowly and allows tectonic plates to move above it.

S-wave shadow zone

The region about 103 to 143 degrees from an earthquake epicenter where S-waves are not recorded, proving the outer core is liquid.

Moho

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

Seafloor spreading

The process in which new oceanic crust forms at mid-ocean ridges and moves away, recorded by symmetric magnetic stripes and increasing seafloor age.

Subduction zone

A convergent boundary where one plate sinks beneath another, forming a trench, earthquakes, and volcanic arcs.

Superposition

The relative dating principle stating that in undisturbed sedimentary layers, the oldest rock is at the bottom and the youngest is at the top.

Half-life

The time required for half of a radioactive sample to decay. It is used in absolute dating to determine the age of rocks and fossils.

Mohs hardness scale

A scale from 1 to 10 ranking mineral resistance to scratching, from talc at 1 to diamond at 10. Quartz ranks 7.

Cleavage

The tendency of a mineral to break along flat planes determined by its atomic structure, as in mica and calcite.

Foliation

Parallel layering or banding in metamorphic rocks caused by pressure aligning mineral grains, as seen in schist and gneiss.

Permeability

The ability of a material to transmit water through connected pore spaces. High permeability allows groundwater to flow quickly.

Lapse rate

The rate at which air temperature decreases with increasing altitude in the troposphere, averaging about 6.5 degrees Celsius per kilometer.

Relative humidity

The ratio of the actual water vapor in air to the maximum amount the air could hold at that temperature, expressed as a percent.

Cold front

The boundary where a cold air mass pushes under a warm air mass, often producing brief, intense precipitation and a rapid temperature drop.

Water table

The upper surface of the saturated zone in the ground, below which all pore spaces are filled with water.

Aquifer

A permeable rock layer that stores and transmits groundwater in usable quantities, often between impermeable confining layers.

Spring tide

An unusually high and low tide that occurs at new and full moon, when the Sun and Moon pull in the same or opposite directions.

Thermohaline circulation

Deep ocean circulation driven by differences in temperature and salinity, which change water density and cause it to sink or rise.

Earth's axial tilt

The 23.5 degree tilt of Earth's axis, which causes the seasons by changing the angle and duration of sunlight through the year.

Lunar eclipse

An event at full moon when Earth passes between the Sun and Moon, casting its shadow on the Moon.

Kepler's third law

The square of a planet's orbital period is proportional to the cube of its average distance from the Sun.

Redshift

The stretching of light from distant galaxies toward longer wavelengths, evidence that the universe is expanding.

Independent variable

The factor in an experiment that is deliberately changed by the investigator, while all other conditions are held constant.

Percent error

A measure of accuracy calculated as the absolute difference between measured and accepted values divided by the accepted value, times 100.

Interpolation

Estimating an unknown value between two known data points on a graph or table, generally more reliable than extrapolation.

Gradient

The rate of change of a field value over distance, calculated as change in value divided by change in distance.

Meniscus

The curved surface of a liquid in a container. Read the bottom of the curve at eye level for an accurate volume measurement.

Triple-beam balance

A laboratory instrument that measures mass by sliding weights along three beams until the pointer balances at zero.