The process by which water vapor becomes liquid water is called "condensation." Condensation occurs when water vapor in the air cools down and loses energy, allowing the molecules to group together and form liquid droplets. This process is critical in the water cycle where condensation leads to cloud formation and precipitation. It can be observed in everyday life, such as water droplets forming on a cold glass or the dew that appears on grass in the morning. Understanding condensation is essential for meteorology, climate science, and various applications including refrigeration and air conditioning systems.