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General review for 8th Grade Science STAAR Review

Worldwide climate change mainly due to increase in CO2 levels

Global Warming

The atmosphere traps solar radiation, because of gases such as CO2, methane and water vapor.

Greenhouse Effect

More harmful UV rays hit earth due to a gradual decrease of the layer of ozone (upper atmosphere); caused by products using chlorofluorcarbons or cfc's.

Ozone depletion

Rock formed from cooling of magma or lava

Igneous rock

Rock formed under heat and pressure

Metamorphic rock

Rock formed from sediments compacting and cementing

Sedimentary rock

Moving sediment


Sinking of the Earth's surface (depletion of groundwater/divergen boundary)

Land Subsidence

A series of changes in the ecosystem that restores equilibrium over time.


Creates soil in primary succession (lichen/moss) first species to appear.

Pioneer Species

New crust is formed at divergen plate boundaries (sea-floor spreading)

Mid-ocean Ridge

movement of Earth's crust

Plate tectonics

Transfer of thermal energy by movements of a fluid. (convection currents)


Rivers of hot or cold water within the ocean caused by planet rotation, wind, temperature and salinity.

Ocean Currents

Transfer of energy by electromagnetic waves (light waves)


Substances moving from areas of greater concentration to areas of less concentration until equilibrium is reached. (examples: heat moves from warmer to cooler areas; gases, nutrients, water moves across a semipermeable membrane)


The way an organism monitors its needs and maintains equilibrium.

Feedback Mechanisms

Water pressure against a cell wall of a plant cell (firm leaf/wilted leaf)

Turgor Pressure

Genetic trait that is represented with a capital letter and will always show if it is present.

Dominant Trait

Genetic makeup; written with symbols (Tt, TT, tt)


Having both the dominant and recessive allele for a trait (Tt)


Having the same allele for a trait (TT, tt)


Physical traits (tall/short)


Relationship between organisms in which one or both benefit.


The measure of an element's ability to combine with other elements, dictated by the number of electrons in the outermost shell.


The tendency of a substance to undergo chemical changes.


Evidence of a new substance; observed when substances interact such as flammability and rusting.

Chemical Properties

The measure of how tight particles of a substance are packed (mass per volume).


What you can observe without the material changing to a new substance (melting, freezing, getting smaller)

Physical Properties

Can be dissolved.


Allowing to pass through.


Not allowing to pass through.


Two or more elements chemically combined.


One or more elements in the same place at the same time, but not chemically combined (like a tossed salad).


Takes in heat during a chemical reaction, will feel cold (ice pack)


Releases heat during a chemcial reaction, will feel warm (decomposition, hand warmers)


Energy of motion (roller coaster increases kinetic energy as it comes down the hill)

Kinetic Energy

Energy that is stored (stress in a fault zone, roller coaster at the top of a hill).

Potential Energy

Molecules expand as more energy is added (alcohol goes up the thermometer showing temperature as heat is added).

Thermal Expansion

The distance an object travels divided by the time it takes to travel that distance.

Average Speed

A graph showing the relationship between time and distance.

Distance-Time Graph

An objects resistance to a change in motion.


The total amount of force acting on an object (all the individual forces are added together).

Net Force

Force that will cause a change in an objects motion.

Unbalanced Force

The change in an objects speed and/or direction; speeding up slowing down, or change in direction.


The shape of the Earth's surface and the way its physical features are arranged; positions and elevations.


Total mass of living organisms in a given area.


The measure of speed and direction.


The range of electromagnetic waves placed in a certain order.

Electromagnetic Spectrum

F = M X A; If an object is acted on by a net force, the change in velocity will be in the direction of the force.

Newton's 2nd Law of Motion

Any material through which a mechanical wave travels.


A giant structure that contains gas, dust, and billions of stars.


A graph relating the temperature and brightness of stars.

Hertzsprung-Russell (H-R) Diagram

Distance light travels in one year.

Light Year

An object at rest will remain at rest unless acted upon by an unbalanced force; an object moving at a constant velocity will remain in the same motion unless acted upon by an unbalanced force.

Newton's 1st Law of Motion

(also known as the manipulated variable) the variable that you change during an experiment.

Independent Variable

(also known as the responding variable) the variable that you expect to change as a response to the manipulated variable.

Dependent Variable

The variable that you keep the same (no change)

Controlled Variable

For every action there is an equal and opposite reaction.

Newton's 3rd Law of Motion

An explanation or model based on observations, experiments, and reasoning, which uses facts to explain and predict natural phenomena.


Flickr Creative Commons Images

Some images used in this set are licensed under the Creative Commons through Click to see the original works with their full license.

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