what is the process by which a vapor becomes a liquid?

The process by which a vapor becomes a liquid is called condensation. This happens when gas molecules (such as water vapor) lose energy, often by cooling down, which slows them and allows their attractions to pull them together to form liquid droplets. In the case of water vapor, this process is common in the water cycle, where water vapor cools and condenses into droplets that form clouds, dew, or fog. Condensation is essentially the reverse of evaporation, where liquid turns into gas.