liquid-gas phase transition

A liquid-gas phase transition occurs when a substance changes between the liquid state (like water) and the gaseous state (like steam). As temperature or pressure change, molecules gain or lose energy, causing nearby molecules to either stick together tightly or move apart. When enough energy is added at a constant pressure, the liquid becomes a gas, often seen as bubbling or boiling. Conversely, cooling a gas under pressure can turn it back into a liquid. This transition involves a specific point called the boiling point, where both phases coexist, and it is described by phase diagrams illustrating the conditions under which each phase exists.