Independent variable - factor that is intentionally changed during an experiment Dependent variable - factor that may change as a result of changes purposely made to the independent variable Variable - a condition that is changed in order to find out the effect of that change Observation - an act or instance of viewing or noting a fact or occurrence for some scientific or other special purpose Hypothesis - a tentative explanation for an observation or phenomenon that can be tested scientifically Constant - variable that stays the same during an experiment Control - sample that is treated like other experimental groups except that the independent variable is not applied to it Density - measures the amount of mass in a given volume Mass - a measure of the amount of matter in an object Volume - the amount of space, measured in cubic units, that an object or substance occupies Weight - a measure of the force of gravity on an object Luster - how the surface of a mineral appears when it reflects light Malleability - a property of metals that makes it capable of being extended or shaped by hammering or by pressure from rollers Conductor - substance that conducts heat readily; also a substance that allows an electric current to pass through it Displacement - one substance or object moving another substance or object, or taking its place