Matter – Definitions matter – Anything that has mass and takes up space. property – A characteristic of matter that can be observed or measured. mass – The amount of matter making up an object. volume – A measure of how much space the matter of an object takes up. buoyancy – The upward force of a liquid or gas on an object. solid – A state of matter that has a definite shape and volume. liquid – A state of matter that has a definite volume but no definite shape. It takes the shape of its container. gas – A state of matter that has no definite shape or volume. metric system – A system of measurement based on units of ten. It is used in most countries and in all scientific work. length – The number of units that fit along one edge of an object. area – The number of unit squares that fit inside a surface. density – The amount of matter in a given space. In scientific terms, density is the amount of mass in a unit of volume. weight – The measure of the pull of gravity between an object and Earth. gravity – A force of attraction, or pull, between objects. physical change – A change that begins and ends with the same type of matter. change of state – A physical change of matter from one state – solid, liquid, or gas – to another state because of a change in the energy of the matter. evaporation – The process of a liquid changing to a gas. rust – A solid brown compound formed when iron combines chemically with oxygen. chemical change – A change that produces new matter with different properties from the original matter. tarnish – Discoloration of metal by exposure to air. mixture – Two or more types of matter that are blended together and keep their own properties. solution – A mixture in which one or more kinds of matter are mixed evenly in another kind of matter..