Question

Why would a pair of eyeglasses fog up when brought from a cold place to a warm place?

A) Water vapor melted from the air onto the glasses.
B) Water vapor condensed from the air onto the glasses.
C) Water vapor evaporated from the air onto the glasses.
D) Water vapor froze from the air onto the glasses.

Answer 1

Eyeglasses fog up when moving from cold to warm areas due to condensation, where water vapor from the warm air condenses on the colder surface of the glasses.

Step-by-step explanation:

A pair of eyeglasses would fog up when brought from a cold place to a warm place because of the phenomenon known as condensation. When the colder eyeglasses come into the warmer air, the temperature of the air in close proximity to the lenses drops below the dew point. This causes water vapor present in the warmer air to condense on the cooler surface of the eyeglasses, forming a layer of visible moisture, or fog. This is the same process observed when condensation forms on the outside of a glass of iced tea.