What Happens After Water Vapor Condenses?

By Annette Strauch
Water vapor condenses into water droplets.

Water in a gaseous state is water vapor. The process of evaporation changes water to vapor, and heat speeds up the process. All air contains water vapor, even the seemingly dry desert air. Water vapor is turned back into liquid water through the process of condensation, the opposite process of evaporation. Water goes through continuous cycles of evaporation and condensation, called the water cycle.



Condensation in the Atmosphere

Water vapor in the atmosphere condenses to cause precipitation.

Water vapor and droplets in the atmosphere combine with tiny particles of dust and other matter. These droplets coalesce (combine), increase in size and form clouds. The cooler temperatures in the atmosphere speed the condensation process. The particles in the clouds eventually become too heavy to remain suspended in the atmosphere, and fall to Earth as some form of precipitation: rain, freezing rain, hail sleet or snow.

Dew

Dew is water vapor that condenses close to the ground.

At night, when temperatures drop, water vapor in the air can condense on surfaces close to the ground, leaving visible water droplets called dew. The point at which the change in form takes place is called the dewpoint. Dew is more likely to form on cloudless nights with little or no wind.

Fog

Warm, humid air blowing across a cool surface can cause fog.

Fog is formed of condensed water droplets when the water vapor in the air near the ground cool. Fog can form after rain cools and dampens low-lying air. Fog can form on a cloudless night if the air is humid, especially in the fall when nights grow longer and cooler. Warm humid air masses that blow over a cool surface, such as the surface of the ocean or a blanket of snow, can also produce fog.

Frost

Frost is water vapor that condenses and freezes.

Frost occurs in a manner similar to dew; but, instead, the dewpoint is near freezing. The water vapor condenses and freezes on surfaces with temperatures below freezing, producing frost.

Other Examples

Water vapor in the air condenses on cold objects, such as a glass with an iced beverage.

Condensation occurs when water vapor cools on the outside of drinking glasses containing cold beverages; on eye glasses when an individual moves from an air-conditioned building outside to hot, humid air; on the inside of car windows from the warm, humid air exhaled by the occupants and on the inside of many windows in the winter.

About the Author

Annette Strauch has been a writer for more than 30 years. She has been a radio news journalist and announcer, movie reviewer for Family Movie Reviews Online, chiropractic assistant and medical writer. Strauch holds a Master of Arts in speech/broadcast journalism from Bob Jones University, where she also served on the faculty of the radio/TV department.