Phaseübergänge

Phaseübergänge, also known as phase transitions, describe the physical processes where a substance changes from one state of matter to another. These transitions occur when external conditions like temperature or pressure are altered, causing the internal energy and structure of the substance to change. The most common examples involve solid, liquid, and gaseous states.

A melting or fusion is the transition from a solid to a liquid, occurring at the melting point. Conversely, solidification or freezing is the transition from a liquid to a solid, happening at the freezing point. Boiling or vaporization is the change from a liquid to a gas, taking place at the boiling point. The reverse process, condensation, is the transition from a gas to a liquid. Sublimation is a direct transition from a solid to a gas, bypassing the liquid phase, while deposition is the reverse process, from gas to solid.

Phaseübergänge are characterized by changes in thermodynamic properties such as enthalpy and entropy. For instance, melting and boiling require energy input, known as latent heat, which is absorbed without a change in temperature. These transitions are fundamental in many scientific and engineering fields, influencing everything from weather patterns to material science. Understanding phaseübergänge is crucial for controlling and predicting the behavior of matter under various conditions.