
The transition of a substance from a dispersed state to a denser, often liquid, state.Condensation is the phase transition of matter from a gas or vapor phase into a liquid or solid phase. In physics, the term is used more broadly to describe any process where a collection of particles transitions from a disordered, dispersed state into a more ordered, denser state. This includes not only the familiar water vapor turning into liquid water, but also the condensation of a gas of atoms into a Bose-Einstein condensate, where a macroscopic number of particles occupy the same quantum state. In biology, condensation refers to the process by which molecules like DNA or proteins cluster together into dense droplets or aggregates.
The concept of condensation has been known since ancient times, but the scientific understanding began with the development of thermodynamics in the 19th century. The quantum version, Bose-Einstein condensation, was predicted by Satyendra Nath Bose and Albert Einstein in 1924-25, and first realized in a laboratory in 1995.
Condensation occurs when the attractive forces between particles overcome their thermal kinetic energy. In a gas, particles move freely and independently. When the temperature is lowered or the pressure is increased, the particles slow down and come closer together. If the attractive forces are strong enough, they bind the particles into a liquid or solid. In quantum condensation, like in a Bose-Einstein condensate, the mechanism is different: at extremely low temperatures, the quantum wave functions of the particles overlap and they all fall into the same lowest-energy state, behaving as a single coherent entity.
Condensation is central to many technologies, from refrigeration and air conditioning to the production of semiconductors via vapor deposition. In biology, understanding liquid-liquid phase separation in cells is a hot research area, as it explains how membrane-less organelles form.
In a Bose-Einstein condensate, atoms move so slowly that they behave like a single 'super atom', and their quantum wave functions overlap over a macroscopic distance, making quantum effects visible to the naked eye.














