A state of matter is one of the distinct forms in which matter can exist, characterized by differences in the arrangement and behavior of its particles (atoms, molecules, or ions). The four classical states of matter observable in everyday life are:
- Solid: Particles are closely packed in a fixed, orderly arrangement. Solids have a definite shape and volume because their particles vibrate but do not move freely
- Liquid: Particles are close together but can move past each other, allowing liquids to have a definite volume but take the shape of their container
- Gas: Particles are far apart and move freely, so gases have neither a fixed shape nor a fixed volume and will expand to fill their container
- Plasma: An ionized state of matter containing free-moving ions and electrons, with variable shape and volume. Plasma is common in the universe but less common on Earth
The state of matter depends on temperature and pressure conditions, and matter can transition between states through phase changes such as melting, freezing, vaporization, condensation, sublimation, and ionization
. Beyond these classical states, other exotic states exist under extreme conditions, such as Bose–Einstein condensates (at very low temperatures) and quark–gluon plasma (at extremely high energy), but these are not commonly encountered in everyday life
. In summary, a state of matter describes the physical form of matter defined by particle arrangement and movement, which determines its shape, volume, and other physical properties.
