There are three main states of matter – solids, liquids, and gases. Each of these states is also known as a phase. Materials can move from one phase to another when physical forces are present. One example of those forces is temperature. The phase or state of matter can change when the temperature changes. Changes of state are energy dependent; they are the product of how particles are interacting with each other. Temperature and pressure affect the way particles interact to change a state or phase. Increase the temperature (a measure of the average speed of particles in an object) and you increase the speed or disorganization of the particles in the object and get a change of state. Increase the pressure and you increase the organization of the particles in the object of study and you get a change of state. These changes of state are a fundamental property of the material. Generally, as the temperature rises, matter moves to a more active state.