How do temperature and other conditions change the state of matter?

In physical science, the state of matter—solid, liquid, or gas—is determined by the balance between the kinetic energy of particles and the forces of attraction acting between them. Changes in these states, known as phase transitions, are primarily driven by variations in temperature and pressure.123

Temperature and Phase Changes

Temperature serves as a measure of the average kinetic energy of particles.13
* Heating: Adding heat provides particles with the energy necessary to overcome attractive forces. For instance, heating a solid provides the heat of fusion required for melting, while further heating provides the heat of vaporization needed for a liquid to enter the gaseous state.13
* Cooling: Removing heat reduces kinetic energy, allowing attractive forces to pull particles closer together. This leads to condensation (gas to liquid) and eventually freezing (liquid to solid).14

Pressure and Structural Transitions

Pressure also plays a critical role in determining the state of matter. Under sufficiently high pressure, materials undergo structural transformations to denser, more closely packed arrangements. For example, high pressure can force gases to solidify or induce transitions in minerals to denser crystalline structures. At extreme pressures, matter may even undergo metallization, where electron orbitals overlap and become delocalized.2