Figure 3.12

Condensation and frost. (A) The cold water in this glass lowered the air temperature around the glass to the dew point. Consequently, liquid water condensed out of the air as a thin film of saturated air formed on the surface of the glass. (B) When the dew point is at or below freezing, deposition forms crystals of ice called hoarfrost or frost. These needles of frost accumulated on hawthorn berries in Bearsden, Scotland. They are about 1 cm (0.5 in) in length and formed in temperatures of about −5°C (23°F).