8th Grade Science

Dwarf planet

A body gravitationally bound to the Sun with enough mass to be approximately spherical in shape, but not enough mass to have pulled in debris from the neighborhood of their orbit.

Change of state or phase

A change from one state (solid or liquid or gas) to another without a change in chemical composition.

Attributes

A characteristic of a thing.

Diagram

A chart, plan or drawing that outlines and explains the parts or operation of something.

Galaxy

A collection of stars, gas, and dust bound together by gravity and isolated from similar systems by vast regions of space.

Characteristic

A distinguishable trait, quality, or property.

Conclusion

A final statement of the findings of an investigative process that is supported by investigative evidence (data).

Fault

A geological rock fracture that shows evidence of relative Earth movement that may extend hundreds or even thousands of kilometers.

Controlled experiment

A laboratory investigation in which the values of all variables are kept the same except for one that is changed from trial to trial and then compared to the rest.

Classification key

A method to group and categorize species of organisms.

Ecosystem

A natural unit consisting of all plants, animals, and microorganisms in an area functioning together with all of the nonliving physical factors of the environment.

Electron

A particle of an atom that carries a negative charge.

Conservation of Mass (energy)

A physical law stating that the total amount of mass remains constant. Also stated as: mass can be neither created nor destroyed during a chemical reaction—only rearranged.

Chemical (change) reaction

A process in which atoms rearrange themselves to form a new substance.

Element

A pure chemical substance composed of all atoms that have the same number of protons.

Force

A push or pull that has both magnitude and direction.

Earthquake

A series of vibrations induced in the earth's crust by the abrupt rupture and rebound of rocks in which elastic strain has been slowly accumulating.

Comet

A small Solar System body that orbits the Sun and, when close enough to the Sun, exhibits a visible tail made of gas and/or dust.

Gas

A state of matter consisting of a collection of particles without a definite shape or volume that are in more or less random motion.

Compound

A substance consisting of two or more different elements chemically bonded together.

Conductor

A substance, body, or device that readily conducts heat, electricity, sound, etc.

Catastrophe

A sudden and widespread disaster as a result of a violent disturbance.

Closed system

A system in which matter may circulate, but may not enter or leave.

Experiment

A test, trial, or tentative procedure with the purpose of discovering something unknown.

Concept map

A visual representation of concepts in a figure, using boxes, arrows, and other symbols to help show relationships between different items. It is a graphical tool for organizing and representing knowledge.

Diversity

A wide variety. Species diversity refers to the abundance of different species within an ecosystem.

Eclipse

An astronomical event that occurs when one celestial object moves into the shadow of another.

Chloroplast

An organelle found in plant cells that's function is to carry out photosynthesis.

Consumer

An organism that gets its chemical energy for growth and development from other organisms. Animals in a food web are consumers that obtain food energy by eating other animals or plants.

Cycle

Any complete round or series of occurrences that repeats or is repeated.

Chemical properties

Any of a material's properties, such as color, pH, boiling point, melting point, density, or it's ability to react with another material.

Evaporation

Change in state of a substance from liquid to gas.

Chromosome

Circular strand of DNA that contains the hereditary information necessary for cell life.

Density

Defined as mass per unit volume.

Chemical Energy

Energy liberated by a chemical reaction or absorbed in the formation of a chemical compound.

Electrical Energy

Energy made available by the flow of electric charge through a conductor.

Characteristic of Life

In order for something to be considered living, it must be made of one or more cells, have organization, use energy, live in stable conditions, grow and reproduce.

Climate

Includes the temperatures, humidity, atmospheric pressure, winds, rainfall, atmospheric particle count, and numerous other meteorological elements in a given region over long periods of time.

Asexual reproduction

Involves one parent and leads to offspring that are genetically identical to the parent and to one another.

Core of the Earth

Most likely a solid sphere about 1,220 km in radius. It is believed to consist of an iron-nickel alloy.

Decomposers

Organisms that consume the remains of dead organisms and break down the tissues into simpler forms of matter that can be used as nutrients for other living organisms.

Crustal plates

Pieces of the Earth's crust that float on the asthenoshere and move in relation to one another.

Asteroid

Small rocky body orbiting the Sun, sometimes called minor planet or planetoid.

Evidence

Tends to prove or disprove something by making observations and measurements, or collecting data through scientific processes.

Crust

The Earth's outermost shell that is composed of a variety of igneous, metamorphic, and sedimentary rocks. Earth's crust includes the oceanic crust, about 7-10 km thick, and the continental crust, about 35-40 km thick.

Adaptation

The ability of a species to survive in a particular environment because of alterations of form or behavior brought about through natural selection.

Formation

The act or process in which a thing is formed or arranged.

Factor

The agent or condition that could cause a change.

Chemical change

The altering of an object's chemical composition (changing what it is made of).

Distance

The amount of space between two points usually measured by length in metric or standard units.

Energy

The amount of work that can be done by a force.

Cells

The basic unit of all living organisms found in both plants and animals, having a nucleus and surrounded by a very thin membrane.

Atoms

The basic unit of matter consisting of a dense central nucleus surrounded by a cloud of negatively charged electrons.

Cytoplasm

The cell substance containing all the organelles outside of the nucleus and enclosed in the cell membrane.

Evolution

The change in the gene pool through a series of gradual or rapid changes of a population from generation to generation by such processes as mutation, natural selection, and genetic drift accounting for the current diversity of species.

Energy transformation

The change of energy from one form to another.

Food web

The complex eating relationships among species within an ecosystem. Organisms are connected to the organisms they consume by arrows representing the direction of energy transfer.

Controlled variables

The conditions that are kept the same from trial to trial in a laboratory investigation.

Extinction

The death of all members of a species of plant or animal. It is generally considered to be the death of the last individual of that species, although the capacity to breed and recover may have been lost before this point.

Biodiversity

The diversity among and within plant and animal species in an environment.

Dependent (responding) variable

The factor studied in a system that is expected to change when the manipulated (independent) variable is changed.

Friction

The force that acts to slow or stop the motion of objects.

Concept

The general notion or idea.

Deposition of sediments

The geologic process following erosion, in which particles of sand or soil are no longer transported from their source by wind or water and are added to a new landform.

DNA

The large molecules inside the nucleus of living cells that carry genetic information.

Atmosphere

The layer of gases that may surround the Earth and other material bodies of sufficient mass.

Composition

The makeup of a material. A material formed from two or more substances.

Average

The mean obtained by adding several quantities together and dividing the sum by the number of quantities.

Average speed

The measure of distance that an object travels in a given time period.

Energy transfer

The movement of energy from one location to another.

Environment

The natural surrounding that includes living and nonliving components. May also refer to a region or to all natural systems on planet Earth.

External

The outside or outer part of a surface.

Fossils

The preserved remains or traces of animals, plants, and other organisms from the remote past.

Feedback

The process by which the output of a system is used to make changes in the operation of the system.

Effect

The result or consequence of an action, influence, or causal agent.

Cell Wall

The rigid boundary or wall made of cellulose that is part of the outer structure of a plant cell.

Field studies

The scientific study of free-living plants or animals in which the subjects are observed in their natural habitat without changing, harming, or materially altering the setting or subjects of the investigation.

Cell Membrane

The semipermeable membrane enclosing the cytoplasm of a cell.

Describe

The skill of developing a detailed picture, image or characterization using diagrams and/or words, written or oral.

Apply

The skill of selecting and using information in new situations or problems.

Anatomy

The structure of an animal or plant, or of any of its parts.

Digestive System

The system by which ingested food is acted upon by physical and chemical means to provide the body with absorbable nutrients and to excrete waste products.

Circulatory System

The system of organs and tissues, including the heart, blood, blood vessels, involved in circulating blood through the body.

Boiling point

The temperature at which a liquid becomes a gas. The boiling point changes as pressure changes.

Convection

The transfer of heat energy by the physical movement of matter. Occurs in liquids and gases.

Conduction

The transfer of heat energy through matter by the movement of molecules.

Explain

To apply scientific ideas to describe the cause of a phenomenon or relationship and/or to render a complex idea plain.

Classify

To arrange in some sort of order by categories or groupings.

Draw

To deduce or infer.

Analyze

To examine carefully and in detail so as to identify causes, key factors and possible results.

Compare

To examine two or more objects or events to establish similarities.

Contrast

To examine two or more objects or events to find differences.

Estimate

To form an approximate judgment or opinion regarding the worth, amount, size, weight, etc., of; calculate approximately.

Dissolve

To make a solution of by mixing with a liquid.

Evaluate

To make judgments based on collected data.

Design

To prepare the plans for work to be executed, such as preparing steps to take to complete a lab.

Bar Graph

Used to illustrate comparative data such as cost, birth rates, etc. by using parallel bars of varying lengths.

Erosion

When solids (sediment, soil, rock and other particles) are carried away or displaced usually by wind, water, or ice by down-slope movement in response to gravity or by living organisms.

Control

a standard condition that other conditions can be compared to in a scientific experiment.

Condensation

the process of changing a gas or vapor to a liquid.