What forms when humid air cools to its dew point and condensation nuclei are present?

What forms when humid air cools to its dew point and condensation nuclei are present?

• A. Dew
• B. Fog
• C. Clouds
• D. Rain

Answer: (C)

Condensation of water vapor onto microscopic particles when air cools to its dew point forms clouds in the atmosphere. When humid air rises, it cools; once it reaches the dew point, water vapor condenses around condensation nuclei such as dust or salt, creating tiny droplets. These droplets can stay suspended and accumulate into visible cloud masses high in the sky. If this same process occurs near the ground, you’d see fog instead of distant clouds, and if droplets grow large enough they can precipitate as rain. Dew, by contrast, forms on surfaces, not in the air, and is not what’s described when the cooling occurs in the air with nuclei present.

Condensation of water vapor onto microscopic particles when air cools to its dew point forms clouds in the atmosphere. When humid air rises, it cools; once it reaches the dew point, water vapor condenses around condensation nuclei such as dust or salt, creating tiny droplets. These droplets can stay suspended and accumulate into visible cloud masses high in the sky. If this same process occurs near the ground, you’d see fog instead of distant clouds, and if droplets grow large enough they can precipitate as rain. Dew, by contrast, forms on surfaces, not in the air, and is not what’s described when the cooling occurs in the air with nuclei present.