 | Term | Definition |
| |
absolute zero |
coldest possible temperature (-273˚C or 0 K) |
| |
acceleration |
the rate of change in velocity |
| |
air resistance |
frictional force air exerts on a moving object; acts opposite in direction to the object's motion. Depends on the object's shape, density, speed, and size |
| |
alternate energy source |
m which energy can be obtained to provide heat, light, and power. Sources of energy have evolved from human and animal power to fossil fuels, uranium, water power, wind, and the Sun |
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amorphous |
lacking distinct crystalline structure |
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ancestor |
a distant or early form of an organism from which later forms descend |
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asexual reproduction |
one parent; identical offspring |
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atomic mass |
the average mass of an element is the average mass of the mixture of its isotopes |
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atomic number |
the number of protons in an atom's nucleus |
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autotroph |
an organism capable of synthesizing its own food from inorganic substances, using light or chemical energy |
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average speed |
a rate of motion determined by dividing the total distance traveled |
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carnivore |
a flesh-eating animal |
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cell |
the smallest structural unit of an organism that is capable of independent functioning, consisting of one or more nuclei, cytoplasm, and various organelles, all surrounded by a semipermeable cell membrane |
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cell membrane |
surrounds the cell and keeps it together; controls the substances passing into and out of the cell |
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cellular respiration |
a process in which cells use oxygen to release energy |
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centripetal force |
the force that causes an object moving along a circular path to move toward the center of the path |
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chemical change |
the change of substances to different substances |
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chemical property |
a characteristic of a substance that indicates whether it can undergo a specific chemical change |
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chlorophyll |
green pigment in plant cells; needed for photosynthesis |
| |
chloroplast |
organelle in plant cells that contains chlorophyll for photosynthesis |
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circuit |
a closed path through which electrons (electricity) flow |
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class |
he usual major subdivision of a phylum or division in tthe classification of organisms, usually consisting of several orders |
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community |
different species living together in a location |
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competition |
competing for resources |
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condensation |
the change of a substance from a gas to a liquid, which usually takes place when a gas is cooled to or below its boiling point |
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conduction |
the transfer of energy through matter in which energy moves from particle to particle |
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conservation |
the process of saving or protecting a natural resource |
| |
consumer |
a living thing that gets its energy by eating other living things in a food chain |
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contract |
movement of molecules toward one another so that they occupy a smaller space |
| |
convection |
the transfer of energy by the bulk movement of matter in which particles move from place to place in a fluid, carrying the energy with them |
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crystalline |
consisting of or containing or of the nature of crystals |
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current |
the flow of electrons through a wire or any conductor; measured in ampheres |
| |
cytoplasm |
gel-like, watery material that contains the cell's organelles (special structures) |
| |
decomposer |
an organism that feeds on and breaks down dead plant or animal matter |
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density |
the mass per unit volume of a material; describes how tightly packed a substance's molecules are |
| |
diffusion |
the tendency of a substance to move from an area of high concentration to an area of lower concentration |
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ecosystem |
community and the nonliving factors with which they interact (abiotic = non-living; biotic = living) |
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egg cell |
the female reproductive cell |
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electrons |
negatively charged particles that move around the nucleus of an atom |
| |
electroscope |
a device containing two suspended metal leaves in a jar that move apart when charged; used to detect the presence of electric charges |
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element |
substance in which all the atoms in a sample are alike |
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environment |
everything that surrounds a living thing; made up of both living and nonliving factors |
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evaporation |
the gradual change of a substance from a liquid to a gas at temperatures below the boiling point |
| |
expand |
outward movement of molecules away from one another so they can occupy a larger space |
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family |
the 18 vertical columns in the periodic table |
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force |
a push or pull one body exerts on another |
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fossil fuel |
source of energy made from the decaying remains of plants and animals |
| |
friction |
the force that opposes motion between two surfaces that are touching each other |
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gas |
a state of matter that is less dense than liquids or solids and has no definite shape or volume |
| |
genus |
the first part of a binomial name that groups together closely related species |
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geothermal energy |
thermal energy source located far below Earth's crust |
| |
gravity |
force exerted by every object in the universe on every other object |
