Dictionary

Depending on parameters like temperature or pressure, matter can exist in different states with greatly varying physical properties. The most important states of matter are the solid, liquid, gaseous and plasma states (the latter three forms of matter are also called fluid). At very low temperatures, atoms bind together to form a solid body with a definite shape. As temperature increases, many solid bodies melt, turning into a liquid or, at even higher temperatures, a gas, an ensemble of atoms and/or molecules wildly scurrying back and forth. A further increase in temperature transforms matter into a plasma. In this state atoms disintegrate into atomic nuclei and electrons.