All matter on Earth exists in one of three phases or states: solid, liquid, or gas. A substance’s current phase is determined by its molecular structure and the amount of kinetic energy its atoms or molecules contain. Adding or removing heat energy to or from a substance can increase its temperature or change it from one phase to another. For example, when enough heat is added to liquid water, it becomes steam. Alternately, when enough heat is removed from liquid water, it becomes ice. This course describes the composition of matter, three phases of matter, physical and chemical properties of substances, liquid flow rates and types of head, and the relationships between pressure, volume, and temperature for gases.
