Matter is anything that has mass and takes up space. There are three states of matter: solids have a definite shape and volume with particles close together and fixed; liquids have an indefinite shape but definite volume, taking the shape of their container with mobile but close particles; gases have an indefinite shape and volume, taking the shape and volume of their container with particles far apart and moving. Properties of matter include physical properties which are observed without changing the substance like color, shape, or boiling point, and chemical properties which are only observed when a substance interacts with another like flammability or rusting. Basic kinds of matter are elements, compounds, and mixtures.