This document discusses the classification and properties of matter. It describes how matter is classified based on physical state as solids, liquids, or gases, and based on chemical composition as pure substances or mixtures. It then discusses the physical nature of matter, explaining that matter is made up of very tiny particles that are in continuous motion and attract one another, even though there is space between them. Finally, it covers the three states of matter and how changing temperature or pressure can cause a change of state, such as melting, boiling, evaporation, and condensation.