When water vapor condenses on a surface below zero degrees Celsius (32 degrees Fahrenheit), it doesn't simply become liquid water. Instead, it undergoes a process called deposition, where it transitions directly from a gaseous state (water vapor) to a solid state (ice).

Here's a breakdown:

* Condensation: Water vapor in the air cools down and loses energy. This causes the water molecules to slow down and clump together, forming liquid water droplets.

* Below Zero Condensation: If the surface temperature is below zero degrees Celsius, the water droplets formed through condensation will immediately freeze, becoming tiny ice crystals.

This process of deposition is responsible for various phenomena:

* Frost: When water vapor in the air comes into contact with a cold surface (like a windowpane or a blade of grass) below freezing, it deposits directly as frost.

* Snow: In clouds, water vapor can deposit directly as ice crystals, which can then grow and fall as snowflakes.

* Freezing Rain: When rain falls through a layer of air below freezing, the water droplets can supercool and remain liquid. Upon contact with a surface below freezing, they freeze instantly, forming a layer of ice.

Therefore, when water vapor condenses on a surface below zero degrees Celsius, it doesn't form liquid water; it directly transforms into solid ice through deposition.