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the knowledge obtained by observing natural events and conditions in order to discover facts and formulate laws or principles that can be verified or tested
a measure of how hot (or cold) something is; specifically, a measure of the average kinetic energy of the particles in an object
in an experiment, the factor that changes in response to the independent variable
the number obtained by adding up the data for a given characteristic and dividing this sum by the number of individuals
a measure of the gravitational force exerted on an object; its value can change with the location of the object in the universe
a characteristic that can be observed or measured without changing the matter's identity
the amount of matter in a given space or volume; the ratio of the mass of a substance to the volume of the substance
a property of matter that describes a substance's ability to participate in chemical reactions
a change that occurs when one or more substances change into entirely new substances with different properties
in physical science, a state of matter that starts as a gas and then becomes ionized; it consists of free-moving ions and electrons, it takes on an electric charge, and its properties differ from the properties of a solid, liquid, or gas; the state of matter that does not have a definite shape or volume and whose particles have broken apart
the conversion of a liquid to a vapor when the vapor pressure of the liquid equals the atmospheric pressure
a substance that cannot be separated or broken down into simpler substances by chemical means
a sample of matter, either a single element or a single compound, that has definite chemical and physical properties
the amount of a particular substance in a given quantity of a mixture, solution, or ore
a subatomic particle that has a positive charge and that is located in the nucleus of an atom; the number of protons in the nucleus is the atomic number, which determines the identity of an element
the number of protons in the nucleus of an atom; the atomic number is the same for all atoms of an element
an atom that has the same number of protons (or the same atomic number) as other atoms of the same element do but that has a different number of neutrons (and thus a different atomic mass)
the rate at which velocity changes overtime; an object accelerates if its speed, direction, or both change
a push or a pull exerted on an object in order to change the motion of the object; force has size and direction
a measure of the gravitational force on an object; its value can change with the location of the object in the universe
the constant velocity of a falling object when the force of air resistance is equal in magnitude and opposite in direction to the force of gravity
the curved path that an object follows when thrown, launched, or otherwise projected near the surface of Earth
the tendency of an object to resist being moved or, if the object is moving, to resist a change in speed or direction until an outside force acts on the object
a nonsolid state of matter in which the atoms or molecules are free to move past each other, as in a gas or liquid
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