| A | B |
|---|
| acceleration | The rate of change of velocity with respect to time |
| acid | a substance that dissolves in water with the formation of hydrogen ions and reacts with a base to form a salt and water. It neutralizes alkalis, dissolves some metals and turns litmus red; typically a corrosive and sour-tasting liquid |
| asteroid | a small rocky body orbiting the sun |
| anemometer | an instrument for measuring and indicating the force or speed of the wind |
| atmosphere | the gaseous envelope surrounding the earth, consists of oxygen, nitrogen and other gases, rotates with Earth |
| atmospheric pressure | the pressure exerted by the atmosphere at the surface of the Earth due to the weight of the air |
| atom | the smallest particle of an element that can exist either alone or in combination |
| atomic number | the number of protons in the nucleus of an atom |
| balance | an instrument for measuring mass |
| barometer | an instrument for determining the pressure of the atmosphere |
| base | a substance that dissolves in water with the formation of hydroxyl ions and reacts with an acid to form a salt and water; turns litmus paper blue |
| capacity | the maximum amount or number that can be contained or accommodated |
| chemical change | a change in a substance resulting in an entirely different substance with different properties from the first |
| chemical property | chemical characteristics of a substance that distinguish it from other substances |
| chemical reaction | a process that involves rearrangement of the molecular or ionic structure of a substance, as opposed to a change in physical form or a nuclear reaction |
| comet | a celestial body that consists of a fuzzy head usually surrounding a bright nucleus, that has a usually highly eccentric orbit, and that often, when in the part of its orbit near the sun, develops a long tail which points away from the sun |
| compostion | the qualitative and quantitative makeup of a chemical compound |
| compound | a substance formed from two or more elements chemically united in fixed proportions |
| condensation | the conversion of a substance (such as water) from the vapor state to a denser liquid or solid state usually initiated by a reduction in the temperature of the vapor |
| conduction | process by which heat or electricity is transmitted through a material or body without movement of the medium itself |
| conservation | a careful preservation and protection of something; especially planned management of a natural resource to prevent exploitation, destruction or neglect |
| control | a group used as a standard of comparison for checking the results of an experiment |
| convection | the circulatory motion that occurs in a fluid at a non-uniform temperature owing to the variation of its density and the action of gravity |
| current | continuous flow as of air, water or electric charge |
| decay rate | the rate at which a radioactive isotope disintegrates until a final non-radioactive isotope is formed |
| decomposers | organisms such as bacteria and fungi that feed and breakdown dead organisms returning constituents of organic substances to the environment |
| dependent variable | a variable whose values are determined by one or more (independent) variables |
| electric field | a region associated with a distribution of electric charge or a varying magnetic field, in which forces due to that charge or field act upon other electric charges |
| electric force | a force that exists between two charges objects |
| electricity | a form of energy resulting from the existence of charged particles, either statically as an accumulation of charge or dynamically as a current |
| electromagnetic radiation | a kind of radiation including visible light, radio waves, gamma rays and x-rays in which electric and magnetic fields vary simultaneously |
| electromagnetic spectrum | the entire range of wavelengths or frequencies of electromagnetic radiation extending from gamma rays to the longest radio waves and including visible light |
| electron | a stable subatomic particle with negative electrical charge, found in all atoms and acting as the primary carrier of electricity in solids |
| element | any of more than 100 fundamental substances that consist of atoms of only one kind and that singly or in combination constitute all matter |
| endothermic | characterized by or formed with absorption of heat |
| energy | the capacity for doing work, can be in various forms such as nuclear, sound, thermal and light |
| equilibrium | a state in which opposing forces or influences are balanced |
| evidence | facts or observations on which a conclusion can be based |
| exothermic | characterized by or formed with liberation of heat |
| faulting | to fracture so as to produce a geologic fault |
| fossil fuel | a fuel (such as coal, oil or natural gas) that is formed in Earth from plant or animal remains |
| frame of reference | an arbitrary set of axes with reference to which the position or motion of something is described or physical laws are formulated |
| friction | the force that resists relative motion between two bodies in contact |
| fusion | the union of atomic nuclei to form heavier nuclei resulting in the release of enormous quantities of energy |
| galaxy | any of the very large groups of stars and associated matter that are found throughout the universe |
| gravitation | a force manifested by acceleration toward each other of two free material particles or bodies, or of radiant-energy quanta |
| gravity | the gravitational attraction of the mass of the Earth, the moon or a planet for bodies at or near its surface |
| hypothesis | a formula derived by inference from scientific data that explains a principle operating in nature |
| igneous | relating to, resulting from, or suggestive of the intrusion or extrusion of magma or volcanic activity |
| independent variable | a variable whose value is specified first and determines the value of one or more other values |
| ion | an atom or group of atoms that carries a positive or negative electric charge as a result of having lost or gained one or more electrons |
| kinetic energy | energy associated with motion |
| landform | a natural feature of a land surface |
| lithosphere | the solid part of a celestial body (such as Earth) specifically the outer part of the solid Earth composed of rock essentially like that exposed at the surface |
| magma | molten rock material within the Earth from which igneous rock results by cooling |
| magnetic reversal | periods of time in which there was a reversal in direction of the Earth's magnetic field |
| mass | the property of a body that is a measure of its inertia and that is commonly taken as a measure of the amount of material it contains causing it to have weight in a gravitational field |
| matter | material substance that occupies space, has mass and is composed of atoms consisting of protons, neutrons and electrons that constitutes the observable universe and that is interchangeable with energy |
| metamorphism | a change in the constitution of rock; specifically a pronounced change affected by pressure, heat and water that results in a more compact and more highly crystalline condition |
| molecule | the smallest particle of a substance that retains all the properties of the substance and is composed of one or more atoms |
| motion | an act, process or instance of changing position through time |
| neutral | neither acidic nor basic (as in pH) |
| neutrons | an uncharged elementary particle that has a mass nearly equal to that of the proton and is present in atomic nuclei |
| nuclear | used in or produced by a nuclear reaction; referring to particles or properties of an atomic nucleus |
| nuclear reaction | a change in the identity or characteristics of an atomic nucleus that results when it is bombarded with an energetic particle |
| nucleus | 1. the positively charged central portion of an atom that comprises nearly all of the atomic mass and that consists of protons and neutrons. 2. the portion of a eukoryotic cell that is surrounded by a nuclear membrane and contains DNA |
| observe | to watch carefully, especially with attention to details or behavior for the purpose of arriving at a judgment |
| orbit | a path described by one body in its revolution about another (as by the Earth about the sun or by an electron about an atomic nucleus |
| periodic table | an arrangement of chemical elements based on the periodic law |
| pH scale | a numerical measure of the acidity or alkalinity of a chemical solution |
| phenomenon | a fact or event of scientific interest susceptible to scientific description and explanation |
| physical change | a change in a substance that does not alter its chemical makeup |
| physical properties | a property of a material that can be observed without changing the chemical makeup of the material |
| planet | any of the large bodies that revolve around the sun in the solar system |
| potential energy | the energy that matter has because of its position or because of the arrangement of atoms or parts |
| property | a quality or trait belonging to an individual or thing |
| proton | a stable subatomic particle occurring in all atomic nuclei with a positive electric charge equal in magnitude to that of an electron |
| qualitative | involving quality or kind |
| quantitative | involving the measurement of quantity or amount |
| radiation | the transfer of heat by radiation (such as energy transfer) The process of emitting radiant energy in the form of waves or particles (such as particle emission) |
| reference point | a basis or standard for evaluation, assessment or comparison: a criterion |
| reflection | the throwing back by a body or surface of light, heat or sound without absorbing it |
| refraction | deflection from a straight path undergone by a light ray or energy wave in passing obliquely from one medium (such as air) into another (such as glass) in which its velocity is different |
| resource | industrial materials and capacities (as mineral deposits and waterpower) supplied by nature (earth science) and substances used by an organism for survival (biology) |
| rotation | the turning of a body part about its long axis as if on a pivot |
| solid | a substance that does not flow perceptibly under moderate stress, has a definite capacity for resisting forces (such as compression or tension) that tend to deform it, and under ordinary conditions retains a definite size and shape |
| sound waves | mechanical radiant energy that is transmitted by longitudinal pressure waves in a material medium (such as air) and is the objective cause of hearing |
| star | a natural luminous body visible in the sky, especially at night |
| technology | human innovation in action that involves the generation of knowledge and processes to develop systems that solve problems and extend human capabilities. The innovation, change, or modification of the natural environment to satisfy perceived human needs and wants |
| theory | a supposition or a system of ideas intended to explain something, especially one based on general principles independent of the thing to be explained |
| tool | a device that aids in accomplishing a task, a form of technology |
| transform | to change in composition or structure |
| variable | a quantity that may assume any one of a set of values |
| velocity | the rate of change of position and direction with respect to time |
| wave | a disturbance or variation that transfers energy progressively from point to point in a medium, and that may take the form of an elastic deformation or of a variation of pressure, electric or magnetic intensity, electric potential or temperature |
