The document defines key terms related to matter including: the definition of matter as anything that has mass and takes up space; the states of matter - solid, liquid, and gas; properties of matter such as density, weight, and buoyancy; and what matter is made of including elements, mixtures, compounds, atoms, and molecules. It also discusses different types of changes that can occur with matter including physical and chemical changes as well as methods of heat transfer such as conduction, convection, and radiation.