Term
|
Definition
| a system of knowledge based on facts or principles |
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|
Term
| technology (tek NAHL uh gee) |
|
Definition
| the application of science to meet human needs |
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|
Term
| scientific law (SIE uhn TIF ik LAW) |
|
Definition
| a summary of an observed natural event |
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|
Term
| scientific theory (SIE uhn TIF ik THEE uh ree) |
|
Definition
| " a tested, possible explanation of a natural event " |
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Term
| critical thinking (KRIT i kuhl THINGK ing) |
|
Definition
| the application of logic and reason to observations and conclusions |
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Term
| scientific method (SIE uhn TIF ik METH uhd) |
|
Definition
| a series of logical steps to follow in order to solve problems |
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Term
| variable (VER ee uh buhl) |
|
Definition
| anything that can change in an experiment |
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Term
|
Definition
| the straight-line distance between any two points |
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Term
|
Definition
| a measure of the quantity of matter in an object |
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Term
|
Definition
| " a measure of space, such as the capacity of a container " |
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Term
|
Definition
| the force with which gravity pulls on a quantity of matter |
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Term
| scientific notation (SIE uhn TIF ik noh TAY shuhn) |
|
Definition
| a value written as a simple number multiplied by a power of 10 |
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Term
| precision (pree SIZH uhn) |
|
Definition
| the degree of exactness of a measurement |
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|
Term
| significant figures (sig NIF uh kuhnt FIG yurz) |
|
Definition
| the digits in a measurement that are known with certainty |
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Term
|
Definition
| the extent to which a measurement approaches the true value |
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Term
|
Definition
| the study of matter and how it changes |
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Term
|
Definition
| anything that has mass and occupies space |
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Term
|
Definition
| the smallest particle that has the properties of an element |
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Term
|
Definition
| a substance made of atoms of more than one element bound together |
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Term
|
Definition
| a substance that cannot be broken down into simpler substances |
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Term
|
Definition
| the smallest unit of a substance that exhibits all of the properties characteristic of that substance |
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Term
| chemical formula (KEM i kuhl FOHR myoo luh) |
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Definition
| the chemical symbols and numbers indicating the atoms contained in the basic unit of a substance |
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Term
|
Definition
| a combination of more than one pure substance |
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|
Term
| pure substance (PYUR SUB stuhns) |
|
Definition
| any matter that has a fixed composition and definite properties |
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Term
| immiscible (im MIS uh buhl) |
|
Definition
| describes two or more liquids that do not dissolve into each other |
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Term
|
Definition
| describes two or more liquids that are able to dissolve into each other in various proportions |
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Term
|
Definition
| the force exerted per unit area of a surface |
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Term
|
Definition
| the ability to change or move matter |
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|
Term
| viscosity (vis KAHS uh tee) |
|
Definition
| the resistance of a fluid to flow |
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|
Term
| condensation (KAHN duhn SAY shuhn) |
|
Definition
| the change of a substance from a gas to a liquid |
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|
Term
| evaporation (ee VAP uh RAY shuhn) |
|
Definition
| the process in which molecules at the surface of a substance change from a liquid to a gas |
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|
Term
| sublimation (SUHB luh MAY shuhn) |
|
Definition
| the change of a substance from a solid to a gas |
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Term
| chemical property (KEM i kuhl PRAHP uhr tee) |
|
Definition
| the way a substance reacts with others to form new substances with different properties |
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|
Term
| boiling point (BOYL ing POYNT) |
|
Definition
| the temperature at which a liquid becomes a gas below the surface |
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|
Term
| melting point (MELT ing POYNT) |
|
Definition
| the temperature at which a solid becomes a liquid |
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|
Term
| physical property (FIZ i kuhl PRAHP uhr tee) |
|
Definition
| a characteristic of a substance that can be observed or measured without changing the composition of the substance |
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|
Term
| reactivity (REE ak TIV i tee) |
|
Definition
| the ability of a substance to combine chemically with another substance |
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|
Term
|
Definition
| the mass per unit volume of a substance |
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|
Term
|
Definition
| the force with which a fluid pushes an object upward |
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|
Term
| chemical change (KEM i kuhl CHAYNJ) |
|
Definition
| a change that occurs when a substance changes composition by forming one or more new substances |
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Term
| physical change (FIZ i kuhl CHAYNJ) |
|
Definition
| a change that occurs in the physical form or properties of a substance that occurs without a change in composition |
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Term
|
Definition
| a tiny negatively charged subatomic particle moving around outside the nucleus of an atom |
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Term
|
Definition
| a neutral subatomic particle in the nucleus of an atom |
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|
Term
|
Definition
| the center of an atom; made up of protons and neutrons |
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|
Term
|
Definition
| a positively charged subatomic particle in the nucleus of an atom |
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|
Term
| energy level (EN uhr jee LEV uhl) |
|
Definition
| any of the possible energies an electron may have in an atom |
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|
Term
|
Definition
| a region in an atom where there is a high probability of finding electrons |
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|
Term
| valence electron (VAY luhns ee LEK trahn) |
|
Definition
| an electron in the outermost energy level of an atom |
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|
Term
| periodic law (PIR ee AHD ik LAW) |
|
Definition
| the properties of elements tend to repeat in a regular pattern when elements are arranged in order of increasing atomic number |
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Term
|
Definition
| a vertical column of elements in the periodic table; also called a family |
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|
Term
|
Definition
| a horizontal row of elements in the periodic table; the time required for one full wavelength to pass a certain point |
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|
Term
|
Definition
| an ion with a negative charge |
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|
Term
|
Definition
| an ion with a positive charge |
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|
Term
|
Definition
| an atom or group of atoms that has lost or gained one or more electrons and therefore has a net electric charge |
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|
Term
| ionization (IE uhn i ZAY shuhn) |
|
Definition
| the process of adding electrons to or removing electrons from an atom or group of atoms |
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|
Term
| atomic number (uh TAHM ik NUHM buhr) |
|
Definition
| the number of protons in the nucleus of an atom |
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|
Term
| mass number (MAS NUHM buhr) |
|
Definition
| the total number of protons and neutrons in the nucleus of an atom |
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|
Term
|
Definition
| any atoms having the same number of protons but different numbers of neutrons |
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|
Term
| atomic mass unit (amu) (uh TAHM ik MAS YOON it) |
|
Definition
| a quantity equal to one-twelfth the mass of a carbon-12 atom |
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|
Term
| average atomic mass (AV uhr ij uh TAHM ik MAS) |
|
Definition
| the weighted average of the masses of all naturally occurring isotopes of an element |
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|
Term
| alkali metals (AL kuh LIE MET uhls) |
|
Definition
| the highly reactive metallic elements located in Group 1 of the periodic table |
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|
Term
|
Definition
| the elements that are good conductors of heat and electricity |
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|
Term
| nonmetals (NAHN MET uhlz) |
|
Definition
| the elements that are usually poor conductors of heat and electricity |
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|
Term
| semiconductors (SEM i kuhn DUHK tuhrz) |
|
Definition
| the elements that are intermediate conductors of heat and electricity |
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|
Term
| alkaline-earth metals (AL kuh LIN UHRTH MET uhls) |
|
Definition
| the reactive metallic elements located in Group 2 of the periodic table |
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|
Term
| transition metals (tran ZISH uhn MET uhls) |
|
Definition
| the metallic elements located in Groups 3–12 of the periodic table |
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|
Term
|
Definition
| the highly reactive elements located in Group 17 of the periodic table |
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|
Term
| noble gases (NOH buhl GAS iz) |
|
Definition
| the unreactive gaseous elements located in Group 18 of the periodic table |
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|
Term
| Avogadro’s constant (AH voh GAH drohz KAHN stuhnt) |
|
Definition
| the number of particles in 1 mol; equals 6.022 3 × 1023/mol |
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|
Term
| molar mass (MOH luhr MAS) |
|
Definition
| the mass in grams of 1 mol of a substance |
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|
Term
|
Definition
| the SI base unit that describes the amount of a substance |
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|
Term
| conversion factor (kuhn VUHR zhuhn FAK tuhr) |
|
Definition
| a ratio equal to one that expresses the same quantity in two different ways |
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|
Term
| chemical bond (KEM i kuhl BAHND) |
|
Definition
| the attractive force that holds atoms or ions together |
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|
Term
| bond angle (BAHND AYN guhl) |
|
Definition
| the angle formed by two bonds to the same atom |
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|
Term
| bond length (BAHND LENGKTH) |
|
Definition
| the average distance between the nuclei of two atoms bonded to each other |
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|
Term
| chemical structure (KEM i kuhl STRUHK chuhr) |
|
Definition
| the arrangement of bonded atoms or ions within a substance |
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|
Term
| ionic bond (IE AHN ik BAHND) |
|
Definition
| a bond formed by the attraction between oppositely charged ions |
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|
Term
| metallic bond (muh TAL ik BAHND) |
|
Definition
| a bond formed by the attraction between positively charged metal ions and the electrons around them |
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|
Term
| covalent bond (KOH VAY luhnt BAHND) |
|
Definition
| a bond formed when atoms share one or more pairs of electrons |
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|
Term
| polyatomic ion (PAHL ee uh TAHM ik IE ahn) |
|
Definition
| an ion made of two or more atoms that are covalently bonded and that act like a single ion |
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|
Term
| empirical formula (em PIR i kuhl FOHR myoo luh) |
|
Definition
| the simplest chemical formula of a compound that tells the smallest whole number ratio of atoms in the compound |
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|
Term
| molecular formula (moh LEK yoo luhr FOHR myoo luh) |
|
Definition
| a chemical formula that reports the actual numbers of atoms in one molecule of a compound |
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|
Term
| organic compound (ohr GAN ik KAHM pownd) |
|
Definition
| any covalently bonded compound that contains carbon |
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|
Term
|
Definition
| a large organic molecule made of many smaller bonded units |
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|
Term
| amino acid (uh MEE noh AS id) |
|
Definition
| any one of 20 different naturally occurring organic molecules that combine to form proteins |
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|
Term
| biochemical compound (BIE oh KEM i kuhl KAHM pownd) |
|
Definition
| any organic compound that has an important role in living things |
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|
Term
| carbohydrate (CAHR boh HIE drayt) |
|
Definition
| " any organic compound that is made of carbon, hydrogen, and oxygen and that provides nutrients to the cells of living things " |
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|
Term
|
Definition
| a biological polymer made of bonded amino acids |
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Term
|
Definition
| a substance that is the result of a chemical change |
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|
Term
|
Definition
| a substance that undergoes a chemical change |
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|
Term
| chemical energy (KEM i kuhl EN uhr jee) |
|
Definition
| the energy stored within atoms and molecules that can be released when a substance reacts |
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|
Term
| endothermic reaction (EN doh THUHR mik ree AK shuhn) |
|
Definition
| " a reaction in which energy is transferred to the reactants from the surroundings, usually as heat " |
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|
Term
| exothermic reaction (EK soh THUHR mik ree AK shuhn) |
|
Definition
| " a reaction that transfers energy from the reactants to the surroundings, usually as heat " |
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|
Term
| synthesis reaction (SIN thuh sis ree AK shuhn) |
|
Definition
| " a reaction of at least two substances that forms a new, more complex compound " |
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|
Term
| combustion reaction (kuhm BUHST shuhn ree AK shuhn) |
|
Definition
| a reaction in which a compound and oxygen burn |
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|
Term
| decomposition reaction (DEE kahm puh ZISH uhn ree AK shuhn) |
|
Definition
| a reaction in which one compound breaks into at least two products |
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|
Term
| electrolysis (EE lek TRAHL i sis) |
|
Definition
| the decomposition of a compound by an electric current |
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|
Term
| single-displacement reaction (SING guhl dis PLAYS muhnt ree AK shuhn) |
|
Definition
| a reaction in which atoms of one element take the place of atoms of another element in a compound |
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|
Term
| double-displacement reaction (DUHB uhl dis PLAYS muhnt ree AK shuhn) |
|
Definition
| " a reaction in which a gas, a solid precipitate, or a molecular compound is formed from the apparent exchange of ions between two compounds " |
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|
Term
|
Definition
| the fragments of molecules that have at least one electron available for bonding |
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|
Term
| reduction/oxidation reaction (redox) (redox ri DUK shuhn AHKS i DAY shuhn) |
|
Definition
| a reaction that occurs when electrons are transferred from one reactant to another |
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|
Term
| chemical equation (KEM i kuhl ee KWAY zhuhn) |
|
Definition
| an equation that uses chemical formulas and symbols to show the reactants and products in a chemical reaction |
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|
Term
| mole ratio (MOHL RAY shee OH) |
|
Definition
| the smallest relative number of moles of the substances involved in a reaction |
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|
Term
|
Definition
| a substance that changes the rate of chemical reactions without being consumed |
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|
Term
|
Definition
| a protein that speeds up a specific biochemical reaction but is not consumed by that reaction; an organic catalyst |
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|
Term
|
Definition
| the specific substance affected by an enzyme |
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|
Term
| equilibrium (EE kwi LIB ree uhm) |
|
Definition
| the state in which a chemical reaction and its reverse occur at the same time and at the same rate |
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|
Term
| suspension (suh SPEN shuhn) |
|
Definition
| a mixture that looks uniform when stirred or shaken but separates into different layers when it is no longer agitated |
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|
Term
|
Definition
| a mixture of very tiny particles of pure substances that are dispersed in another substance but do not settle out of the substance |
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|
Term
|
Definition
| a stable suspension consisting of an immiscible liquid dispersed and held in another liquid |
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|
Term
|
Definition
| the substance that dissolves in a solution |
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|
Term
|
Definition
| a homogeneous mixture of two or more substances uniformly spread throughout a single phase |
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|
Term
|
Definition
| the substance that dissolves the solute to make a solution |
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|
Term
| concentration (kahn suhn TRAY shuhn) |
|
Definition
| the quantity of solute dissolved in a given quantity of solution |
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|
Term
| saturated solution (SACH uh RAYT id suh LOO shuhn) |
|
Definition
| a solution that cannot dissolve any more solute at the given conditions |
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|
Term
| unsaturated solution (UHN SACH uh RAYT uhd suh LOO shuhn) |
|
Definition
| a solution that is able to dissolve more solute |
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|
Term
| solubility (SAHL yoo BIL uh tee) |
|
Definition
| the greatest quantity of a solute that will dissolve in a given quantity of solvent to produce a saturated solution |
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|
Term
| supersaturated solution (SOO puhr SACH uh RAYT uhd suh LOO shuhn) |
|
Definition
| a solution holding more dissolved solute than is specified by its solubility at a given temperature |
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|
Term
|
Definition
| a concentration unit of a solution that expresses moles of solute dissolved per liter of solution |
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|
Term
|
Definition
| " a substance that donates protons, H+, to form hydronium ions, H3O+, when dissolved in water " |
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|
Term
| indicator (IN di KAYT uhr) |
|
Definition
| " a compound that can reversibly change color in a solution, depending on the concentration of H3O+ ions " |
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|
Term
|
Definition
| " a substance that either contains hydroxide ions, OH–, or reacts with water to form hydroxide ions " |
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|
Term
|
Definition
| a measure of the hydronium ion concentration in a solution |
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|
Term
| neutralization reaction (NOO truhl i ZAY shuhn ree AK shuhn) |
|
Definition
| a reaction in which hydronium ions from an acid and hydroxide ions from a base react to produce water molecules |
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|
Term
|
Definition
| " an ionic compound composed of cations bonded to anions, other than oxide or hydroxide anions " |
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|
Term
|
Definition
| a cleaner that dissolves in both water and oil |
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|
Term
| detergent (dee TUHR jent) |
|
Definition
| a nonsoap water-soluble cleaner that can emulsify dirt and oil |
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Term
|
Definition
| a basic solution that can either be used as a disinfectant or to remove colors and stains |
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|
Term
| disinfectant (DIS in FEK tuhnt) |
|
Definition
| a substance that kills harmful bacteria or viruses |
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|
Term
|
Definition
| a weak base that neutralizes excess stomach acid |
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|
Term
| nuclear radiation (NOO klee uhr RAY dee AY shuhn) |
|
Definition
| the charged particles or energy emitted by an unstable nucleus |
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|
Term
| radioactivity (RAY dee oh ak TIV uh tee) |
|
Definition
| a process by which an unstable nucleus emits one or more particles or energy |
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|
Term
| alpha particle (AL fuh PAHRT i kuhl) |
|
Definition
| " a positively charged particle, emitted by some radioactive nuclei, that consists of two protons and two neutrons " |
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|
Term
| beta particle (BAYT uh PAHRT i kuhl) |
|
Definition
| an electron emitted during the radioactive decay of a neutron in an unstable nucleus |
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|
Term
|
Definition
| the high-energy electromagnetic radiation emitted by a nucleus during radioactive decay |
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|
Term
| neutron emission (NOO trahn ee MISH uhn) |
|
Definition
| the release of a high-energy neutron by some neutron-rich nuclei during radioactive decay |
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|
Term
|
Definition
| the time required for half a sample of radioactive nuclei to decay |
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|
Term
| strong nuclear force (STRAWNG NOO klee uhr FOHRS) |
|
Definition
| the force that binds protons and neutrons together in a nucleus |
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|
Term
|
Definition
| " the process by which a nucleus splits into two or more smaller fragments, releasing neutrons and energy " |
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|
Term
| nuclear chain reaction (NOO klee uhr CHAYN ree AK shuhn) |
|
Definition
| a series of fission processes in which the neutrons emitted by a dividing nucleus cause the division of other nuclei |
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|
Term
| critical mass (KRIT i kuhl MAS) |
|
Definition
| the minimum mass of a fissionable isotope in which a nuclear chain reaction can occur |
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|
Term
|
Definition
| " the process in which light nuclei combine at extremely high temperatures, forming heavier nuclei and releasing energy " |
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|
Term
| background radiation (BAK grownd RAY dee AY shuhn) |
|
Definition
| the nuclear radiation that arises naturally from cosmic rays and from radioactive isotopes in the soil and air |
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|
Term
| radioactive tracer (RAY dee oh AK tiv TRAYS uhr) |
|
Definition
| a radioactive material added to a substance so that the substance’s location can later be detected |
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|
Term
|
Definition
| the distance traveled divided by the time interval during which the motion occurred |
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|
Term
| velocity (vuh LAHS uh tee) |
|
Definition
| a quantity describing both speed and direction |
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|
Term
|
Definition
| a quantity defined as the product of an object’s mass and velocity |
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|
Term
| acceleration (ak SEL uhr AY shuhn) |
|
Definition
| the change in velocity divided by the time interval in which the change occurred |
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|
Term
|
Definition
| " the cause of an acceleration, or change in an object’s velocity " |
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|
Term
| balanced forces (BAL uhnst FOHR sez) |
|
Definition
| the forces acting on an object that combine to produce a net force that is equal to zero |
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|
Term
| unbalanced forces (UHN BAL uhnst FOHR sez) |
|
Definition
| the forces acting on an object that combine to produce a net nonzero force |
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|
Term
|
Definition
| the force between two objects in contact that opposes the motion of either object |
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|
Term
|
Definition
| the force of attraction between two particles of matter due to their mass |
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|
Term
|
Definition
| the tendency of an object to remain at rest or in motion with a constant velocity |
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|
Term
|
Definition
| the motion of a body when only the force of gravity is acting on it |
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|
Term
| terminal velocity (TUHR muh nuhl vuh LAHS uh tee) |
|
Definition
| " the maximum velocity reached by a falling object, occurring when resistance of the medium is equal to the force due to gravity " |
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|
Term
|
Definition
| a quantity that measures the effects of a force acting over a distance |
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|
Term
|
Definition
| a quantity that measures the rate at which work is done |
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|
Term
| mechanical advantage (muh KAN i kuhl ad VANT ij) |
|
Definition
| a quantity that measures how much a machine multiplies force or distance |
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|
Term
| simple machine (SIM puhl muh SHEEN) |
|
Definition
| any one of the six basic types of machines of which all other machines are composed |
|
|
Term
| compound machine (KAHM pownd muh SHEEN) |
|
Definition
| a machine made of more than one simple machine |
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|
Term
| potential energy (poh TEN shuhl EN uhr jee) |
|
Definition
| the stored energy resulting from the relative positions of objects in a system |
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|
Term
| kinetic energy (ki NET ik EN uhr jee) |
|
Definition
| the energy of a moving object due to its motion |
|
|
Term
| mechanical energy (muh KAN i kuhl EN uhr jee) |
|
Definition
| the sum of the kinetic and potential energy of large-scale objects in a system |
|
|
Term
| efficiency (e FISH uhn see) |
|
Definition
| " a quantity, usually expressed as a percentage, that measures the ratio of useful work output to work input " |
|
|
Term
| temperature (TEM puhr uh chuhr) |
|
Definition
| a measure of the average kinetic energy of all the particles within an object |
|
|
Term
| thermometer (thuhr MAHM uht uhr) |
|
Definition
| a device that measures temperature |
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|
Term
| absolute zero (AB suh LOOT ZIR oh) |
|
Definition
| the temperature at which an object’s energy is minimal |
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|
Term
|
Definition
| the transfer of energy from the particles of one object to those of another object due to a temperature difference |
|
|
Term
| conduction (kuhn DUK shuhn) |
|
Definition
| the transfer of energy as heat between particles as they collide within a substance or between two objects in contact |
|
|
Term
| convection (kuhn VEK shuhn) |
|
Definition
| the transfer of energy by the movement of fluids with different temperatures |
|
|
Term
| convection current (kuhn VEK shuhn KUHR uhnt) |
|
Definition
| the flow of a fluid due to heated expansion followed by cooling and contraction |
|
|
Term
| radiation (RAY dee AY shuhn) |
|
Definition
| the transfer of energy by electromagnetic waves |
|
|
Term
| conductor (kuhn DUK tuhr) |
|
Definition
| a material through which energy can be easily transferred as heat; also a material that transfers charge easily |
|
|
Term
| insulator (IN suh LAYT uhr) |
|
Definition
| a material that is a poor energy conductor; a material that does not transfer charge easily |
|
|
Term
| specific heat (spuh SIF ik HEET) |
|
Definition
| the amount of energy transferred as heat that will raise the temperature of 1 kg of a substance by 1 K |
|
|
Term
| heating system (HEET ing SIS tuhm) |
|
Definition
| a device that transfers energy as heat to a substance to raise the temperature of the substance |
|
|
Term
| cooling system (KOOL ing SIS tuhm) |
|
Definition
| a device that transfers energy as heat out of an object to lower the object’s temperature |
|
|
Term
| refrigerant (ri FRIJ uhr uhnt) |
|
Definition
| a substance used in cooling systems that transfers large amounts of energy as it changes state |
|
|
Term
|
Definition
| a disturbance that transmits energy through matter or space |
|
|
Term
| electromagnetic wave (ee LEK troh mag NET ik WAYV) |
|
Definition
| a wave that is caused by a disturbance in electric and magnetic fields and that does not require a medium; also called a light wave |
|
|
Term
| mechanical wave (muh KAN i kuhl WAYV) |
|
Definition
| a wave that requires a medium through which to travel |
|
|
Term
|
Definition
| the matter through which a wave travels |
|
|
Term
| longitudinal wave (LAHN juh TOOD uhn uhl WAYV) |
|
Definition
| a wave that causes the particles of the medium to vibrate parallel to the direction the wave travels |
|
|
Term
| transverse wave (TRANS VUHRS WAYV) |
|
Definition
| a wave that causes the particles of the medium to vibrate perpendicularly to the direction the wave travels |
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Term
|
Definition
| the greatest distance that particles in a medium move from their normal position when a wave passes by |
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Term
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Definition
| the highest point of a transverse wave |
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Term
|
Definition
| the lowest point of a transverse wave |
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Term
|
Definition
| the distance between any two successive identical parts of a wave |
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Term
| frequency (FREE kwuhn see) |
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Definition
| the number of vibrations that occur in a 1 s time interval |
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Term
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Definition
| the speed at which a wave passes through a medium |
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Term
| Doppler effect (DAHP luhr e FEKT) |
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Definition
| an observed change in the frequency of a wave when the source or observer is moving |
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Term
| reflection (ri FLEK shuhn) |
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Definition
| the bouncing back of a wave as it meets a surface or boundary |
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Term
| diffraction (di FRAK shuhn) |
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Definition
| the bending of a wave as it passes an edge or an opening |
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Term
| interference (IN tuhr FIR uhns) |
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Definition
| the combination of two or more waves that exist in the same place at the same time |
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Term
| refraction (ri FRAK shuhn) |
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Definition
| the bending of waves as they pass from one medium to another |
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Term
| constructive interference (kuhn STRUHK tiv IN tuhr FIR uhns) |
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Definition
| any interference in which waves combine so that the resulting wave is bigger than the original waves |
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Term
| destructive interference (di STRUK tiv IN tuhr FIR uhns) |
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Definition
| any interference in which waves combine so that the resulting wave is smaller than the largest of the original waves |
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Term
| standing wave (STAN ding WAYV) |
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Definition
| a wave form caused by interference that appears not to move along the medium and that shows some regions of no vibration (nodes) and other regions of maximum vibration (antinodes) |
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Term
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Definition
| " the perceived highness or lowness of a sound, depending on the frequency of sound waves " |
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Term
| infrasound (IN fruh SOWND) |
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Definition
| any sound consisting of waves with frequencies lower than 20 Hz |
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Term
| ultrasound (UHL truh SOWND) |
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Definition
| any sound consisting of waves with frequencies higher than 20 000 Hz |
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Term
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Definition
| an effect in which the vibration of one object causes the vibration of another object at a natural frequency |
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Term
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Definition
| " a system that uses reflected sound waves to determine the distance to, and location of, objects " |
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Term
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Definition
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Term
| intensity (in TEN suh tee) |
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Definition
| the rate at which light or any other form of energy flows through a given area of space |
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Term
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Definition
| a system that uses reflected radio waves to determine the distance to and location of objects |
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Term
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Definition
| a model of light that represents light traveling through space in an imaginary straight line |
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Term
| virtual image (VUHR choo uhl IM ij) |
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Definition
| an image that forms at a point from which light rays appear to come but do not actually come |
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Term
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Definition
| an image of an object formed by many light rays coming together in a specific location |
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Term
| total internal reflection (TOHT uhl in TUHR nuhl ri FLEK shuhn) |
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Definition
| the compete reflection of light at the boundary between two transparent mediums when the angle of incidence exceeds the critical angle |
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Term
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Definition
| " a transparent object that refracts light rays, causing them to converge or diverge to create an image " |
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Term
| magnification (MAG nuh fi KAY shuhn) |
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Definition
| a change in the size of an image compared with the size of an object |
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Term
| dispersion (di SPUHR zhuhn) |
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Definition
| an effect in which white light separates into component colors |
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Term
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Definition
| a transparent block with a triangular cross section |
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Term
| electric charge (ee LEK trik CHAHRJ) |
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Definition
| an electrical property of matter that creates a force between objects |
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Term
| electric force (ee LEK trik FOHRS) |
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Definition
| the force of attraction or repulsion between objects due to charge |
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Term
| electric field (ee LEK trik FEELD) |
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Definition
| the region around a charged object in which other charged objects experience an electric force |
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Term
| electrical potential energy (ee LEK tri kuhl poh TEN shuhl EN uhr jee) |
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Definition
| the potential energy of a charged object due to its position in an electric field |
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Term
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Definition
| " a device that is a source of electric current because of a potential difference, or voltage, between the terminals " |
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Term
| potential difference (poh TEN shuhl DIF uhr uhns) |
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Definition
| the change in the electrical potential energy per unit charge |
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Term
|
Definition
| the rate that electric charges move through a conductor |
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Term
| resistance (ri ZIS tuhns) |
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Definition
| the ratio of the voltage across a conductor to the current it carries |
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Term
| electric circuit (ee LEK trik SUHR kit) |
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Definition
| an electrical device connected so that it provides one or more complete paths for the movement of charges |
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Term
| schematic diagram (skee MAT ik DIE uh GRAM) |
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Definition
| " a graphic representation of an electric circuit or apparatus, with standard symbols for the electrical devices " |
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Term
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Definition
| " describes components in a circuit that are connected across common points, providing two or more separate conducting paths " |
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Term
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Definition
| describes a circuit or portion of a circuit that provides a single conducting path |
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Term
| electrical energy (ee LEK tri kuhl EN uhr jee) |
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Definition
| " the energy associated with electrical charges, whether moving or at rest " |
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Term
| circuit breaker (SUHR kit BRAYK uhr) |
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Definition
| a device that protects a circuit from current overloads |
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Term
|
Definition
| an electrical device containing a metal strip that melts when current in the circuit becomes too great |
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Term
| magnetic pole (mag NET ik POHL) |
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Definition
| an area of a magnet where the magnetic force appears to be the strongest |
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Term
| magnetic field (mag NET ik FEELD) |
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Definition
| a region where a magnetic force can be detected |
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Term
|
Definition
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Term
| electromagnet (ee LEK troh MAG nit) |
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Definition
| a strong magnet created when an iron core is inserted into the center of a current-carrying solenoid |
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Term
|
Definition
| a microscopic magnetic region composed of a group of atoms whose magnetic fields are aligned in a common direction |
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Term
| galvanometer (GAL vuh NAH muht uhr) |
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Definition
| an instrument that measures the amount of current in a circuit |
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Term
| electric motor (ee LEK trik MOHT uhr) |
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Definition
| a device that converts electrical energy to mechanical energy |
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Term
| electromagnetic induction (ee LEK troh mag NET ik in DUHK shuhn) |
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Definition
| " the production of a current in a circuit by a change in the strength, position, or orientation of an external magnetic field " |
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Term
| alternating current (AWL tuhr NAYT ing KUHR uhnt) |
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Definition
| an electric current that changes direction at regular intervals; also called AC |
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Term
| generator (JEN uhr AYT uhr) |
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Definition
| a device that uses electromagnetic induction to convert mechanical energy to electrical energy |
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Term
| transformer (trans FOHRM uhr) |
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Definition
| a device that can change one alternatingcurrent voltage to a different alternating-current voltage |
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Term
|
Definition
| " a sign that represents information, such as a command, a direction, or a warning " |
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Term
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Definition
| a set of rules used to interpret signals that convey information |
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Term
| telecommunication (TEL i kuh MYOO ni KAY shuhn) |
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Definition
| a communication method using electromagnetic means |
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Term
| analog signal (AN uh LAWG SIG nuhl) |
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Definition
| a signal corresponding to a quantity whose values can change continuously |
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Term
| digital signal (DIJ i tuhl SIG nuhl) |
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Definition
| a signal that can be represented as a sequence of discrete values |
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Term
| optical fiber (AHP ti kuhl FIE buhr) |
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Definition
| " a hair-thin, transparent strand of glass or plastic that transmits signals using pulses of light " |
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Term
| atmospheric transmission (AT muhs FIR ik trans MISH uhn) |
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Definition
| the transmission of a signal using electromagnetic waves |
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Term
| physical transmission (FIZ i kuhl trans MISH uhn) |
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Definition
| " the transmission of a signal using wires, cables, or optical fibers " |
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Term
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Definition
| a continuous wave that can be modulated to send a signal |
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Term
|
Definition
| the process of changing a wave’s amplitude or frequency in order to send a signal |
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Term
| cathode ray tube (CATH OHD RAY TOOB) |
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Definition
| a tube that uses an electron beam to create a display on a phosphorescent screen |
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Term
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Definition
| the smallest element of a display image |
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Term
|
Definition
| " an electronic device that can accept data and instructions, follow the instructions, and output the results " |
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Term
| random-access memory (RAM) (RAN duhm AK SES MEM uh ree) |
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Definition
| a storage device that allows any stored data to be read in the same access time |
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Term
|
Definition
| the equipment that makes up a computer system |
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Term
| operating system (AHP uhr AYT ing SIS tuhm) |
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Definition
| the software that controls a computer’s activities |
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Term
| read-only memory (ROM) (REED OHN lee MEM uh ree) |
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Definition
| a memory device containing data that cannot be changed |
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Term
|
Definition
| " the instructions, data, and programming that enables a computer system to work " |
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Term
|
Definition
| a large computer network that connects many local and smaller networks |
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Term
|
Definition
| " the sum of all matter and energy that exists, that ever has existed, and that ever will exist " |
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Term
|
Definition
| a collection of millions or billions of stars bound together by gravity |
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Term
|
Definition
| a unit of distance equal to the distance light travels in one year; 1 ly = 9.5 × 1015 m |
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Term
|
Definition
| a huge ball of hot gas that emits light |
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Term
| interstellar matter (IN tuhr STEL uhr MA tuhr) |
|
Definition
| the gas and dust between the stars in a galaxy |
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Term
|
Definition
| a group of galaxies bound by gravity |
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Term
|
Definition
| a shift toward the red end of the spectrum in the observed spectral lines of stars or galaxies |
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Term
| big bang theory (BIG BANG THEE uh ree) |
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Definition
| a scientific theory that states that the universe began 10 billion to 20 billion years ago in an enormous explosion |
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Term
| constellation (KAHN stuh LAY shuhn) |
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Definition
| a group of stars appearing in a pattern as seen from Earth |
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Term
|
Definition
| " a large, reddish star late in its life cycle that fuses helium into carbon or oxygen " |
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Term
| supergiant (SOO puhr JI uhnt) |
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Definition
| an extremely large star that creates elements as heavy as iron |
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Term
| supernova (SOO puhr NOH vuh) |
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Definition
| a powerful explosion that occurs when a massive star dies |
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Term
| white dwarf (HWIET DWOHRF) |
|
Definition
| " a small, very dense star that remains after fusion in a red giant stops " |
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Term
|
Definition
| an object so massive and dense that not even light can escape its gravity |
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Term
| neutron star (NOO trahn STAHR) |
|
Definition
| a dead star with the density of atomic nuclei |
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Term
|
Definition
| any of the nine primary bodies orbiting the sun; a similar body orbiting another star |
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Term
| solar system (SOH luhr SIS tuhm) |
|
Definition
| the sun and all the objects that orbit around it |
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Term
|
Definition
| " a small rocky object that orbits the sun, usually in a band between the orbits of Mars and Jupiter " |
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Term
| nebular model (NEB yuh luhr MAHD uhl) |
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Definition
| a model that describes the sun and the solar system forming together out of a cloud of gas and dust |
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Term
|
Definition
| an event that occurs when one object passes into the shadow of another object |
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Term
|
Definition
| " the different apparent shapes of the moon or a planet due to the relative positions of the sun, Earth, and the moon or planet " |
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Term
|
Definition
| the outermost and thinnest layer of Earth |
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Term
|
Definition
| the layer of rock between Earth’s crust and its core |
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Term
|
Definition
| " the center of a planetary body, such as Earth " |
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Term
| lithosphere (LITH oh SFIR) |
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Definition
| " the thin outer shell of Earth, consisting of the crust and the rigid upper mantle " |
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Term
| plate tectonics (PLAYT tek TAHN iks) |
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Definition
| the theory that Earth’s surface is made up of large moving plates |
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Term
| asthenosphere (as THEN uh SFIR) |
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Definition
| the zone of the mantle beneath the lithosphere that consists of slowly flowing solid rock |
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Term
|
Definition
| the molten rock within Earth |
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|
Term
| subduction (suhb DUHK shuhn) |
|
Definition
| the process in which a tectonic plate dives beneath another tectonic plate and into the asthenosphere |
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Term
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Definition
| a crack in Earth created when rocks on either side of a break move |
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Term
| epicenter (EP i SEN tuhr) |
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Definition
| the point on Earth’s surface directly above the focus of an earthquake |
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Term
|
Definition
| " the area along a fault at which slippage first occurs, initiating an earthquake " |
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|
Term
|
Definition
| primary waves; the longitudinal waves generated by an earthquake |
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Term
|
Definition
| secondary waves; the transverse waves generated by an earthquake |
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Term
| seismology (siez MAHL uh gee) |
|
Definition
| the study of earthquakes and related phenomena |
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Term
| surface waves (SUHR fis WAYVZ) |
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Definition
| the seismic waves that travel along Earth’s surface |
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Term
| Richter scale (RIK tuhr SKAYL) |
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Definition
| a scale that expresses the relative magnitude of an earthquake |
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Term
|
Definition
| an opening through which molten rock flows onto Earth’s surface |
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Term
|
Definition
| " a natural, inorganic solid with a definite chemical composition and a characteristic internal structure " |
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Term
| igneous rock (IG nee uhs RAHK) |
|
Definition
| any rock formed from cooled and hardened magma or lava |
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Term
|
Definition
| the traces or remains of a plant or an animal found in sedimentary rock |
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|
Term
| sedimentary rock (SED uh MEN tuh ree RAHK) |
|
Definition
| any rock formed from compressed or cemented deposits of sediment |
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Term
| weathering (WETH uhr ing) |
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Definition
| the change in the physical form or chemical composition of rock materials exposed at Earth’s surface |
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Term
| metamorphic rock (MET uh MOHR fik RAHK) |
|
Definition
| " any rock formed from other rocks as a result of heat, pressure, or chemical processes " |
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Term
|
Definition
| any precipitation that has an unusually high concentration of sulfuric or nitric acids resulting from chemical pollution of the air |
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|
Term
| deposition (DE puh ZISH uhn) |
|
Definition
| the process in which sediment is laid down |
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Term
|
Definition
| the process by which rock and/or the products of weathering are removed |
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Term
| temperature inversion (TEM puhr uh chuhr in VUHR zhuhn) |
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Definition
| the atmospheric condition in which warm air traps cooler air near Earth’s surface |
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|
Term
| troposphere (TRO poh SFIR) |
|
Definition
| the atmospheric layer closest to Earth’s surface where nearly all weather occurs |
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Term
|
Definition
| the form of atmospheric oxygen that has three atoms per molecule |
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Term
| stratosphere (STRAT uh SFIR) |
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Definition
| the layer of the atmosphere that extends upward from the troposphere to an altitude of 50 km; contains the ozone layer |
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Term
|
Definition
| the coldest layer of the atmosphere; located above the stratosphere |
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|
Term
| thermosphere (THURM oh SFIR) |
|
Definition
| the atmospheric layer above the mesosphere |
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Term
| greenhouse effect (GREEN HOWS e FEKT) |
|
Definition
| the process by which the atmosphere traps some of the energy from the sun in the troposphere |
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|
Term
| water cycle (WAH tuhr SIE kuhl) |
|
Definition
| the continuous movement of water from the atmosphere to Earth and back |
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|
Term
| humidity (hyoo MID uh tee) |
|
Definition
| the quantity of water vapor in the atmosphere |
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|
Term
| precipitation (pree SIP uh TAY shuhn) |
|
Definition
| " any form of water that falls back to Earth’s surface from clouds; includes rain, snow, sleet, and hail " |
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|
Term
| relative humidity (REL uh tiv hyoo MID uh tee) |
|
Definition
| the ratio of the quantity of water vapor in the air to the maximum quantity of water vapor that can be present at that temperature |
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|
Term
| transpiration (TRAN spuh RAY shuhn) |
|
Definition
| the evaporation of water through pores in a plant’s leaves |
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Term
|
Definition
| the temperature at which water vapor molecules start to form liquid water |
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|
Term
| barometric pressure (BAR uh ME trik PRESH uhr) |
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Definition
| the pressure due to the weight of the atmosphere; also called air pressure or atmospheric pressure |
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|
Term
| Coriolis effect (KOHR ee OH lis e FEKT) |
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Definition
| the change in the direction of an object’s path due to Earth’s rotation |
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|
Term
|
Definition
| a large body of air with uniform temperature and moisture content |
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|
Term
|
Definition
| the boundary between air masses of different densities |
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Term
|
Definition
| the general weather conditions over many years |
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|
Term
|
Definition
| a line drawn on a weather map connecting points of equal barometric or atmospheric pressure |
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|
Term
| topography (tuh PAHG ruh fee) |
|
Definition
| the surface features of Earth |
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|
Term
| ecosystem (EK oh SIS tuhm) |
|
Definition
| all of the living and nonliving elements in a particular place |
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|
Term
| community (kuh MYOO nuh tee) |
|
Definition
| all of the animals and plants living in one area in an ecosystem |
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|
Term
| succession (suhk SESH uhn) |
|
Definition
| the gradual repopulating of a community by different species over a period of time |
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|
Term
| hydroelectric power (HIE DROH ee LEK trik POW uhr) |
|
Definition
| power produced when the energy of moving water is converted to electricity |
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|
Term
| fossil fuels (FAHS uhl FYOO uhlz) |
|
Definition
| any fuels formed from the remains of ancient plant and animal life |
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|
Term
| nonrenewable resources (NAHN ri NOO uh buhl REE sohrs uz) |
|
Definition
| any resources that are used faster than they can be replaced |
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|
Term
| renewable resources (ri NOO uh buhl REE sohrs uhz) |
|
Definition
| any resources that can be continually replaced |
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|
Term
| geothermal energy (JEE oh THUHR muhl EN uhr jee) |
|
Definition
| the energy drawn from heated water within Earth’s crust |
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|
Term
| pollution (puh LOO shuhn) |
|
Definition
| " the contamination of the air, water, or soil " |
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|
Term
| global warming (GLOH buhl WAHRM ing) |
|
Definition
| an increase in Earth’s temperature due to an increase in greenhouse gases |
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|
Term
| eutrophication (yoo TRAHF i KAY shuhn) |
|
Definition
| " an increase in the amount of nutrients, such as nitrates, in an environment " |
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|
Term
| recycling (ree SIE kuhl ing) |
|
Definition
| the process of breaking down discarded material for re-use in other products |
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