Question

why does a glass filled with a cold beverage seem to \sweat\?
multiple choice
saturation always results in \sweat\ on wet objects.
evaporation of the beverage cools the glass, and condensation of water from the evaporated beverage follows.
when cold, water molecules can move through tiny pores in the glass.
the cold glass cools adjacent air to saturation, which is followed by condensation of water vapor.

Explanation:

When a glass is filled with a cold beverage, the temperature of the glass is lower than the dew - point temperature of the surrounding air. The cold glass cools the adjacent air. As the air cools, its capacity to hold water vapor (saturation vapor pressure) decreases. When the air is cooled to its dew - point temperature (saturation), water vapor in the air condenses on the surface of the glass.

• The first option is incorrect because saturation alone does not cause "sweating" on all wet objects in this context.
• The second option is wrong as the "sweat" is not from the evaporation of the beverage and then condensation of that same evaporated beverage. The "sweat" is from the condensation of atmospheric water vapor.
• The third option is incorrect because glass is generally non - porous (or if it has pores, they are not relevant to this "sweating" phenomenon which is a result of condensation from the air).

Answer:

The cold glass cools adjacent air to saturation, which is followed by condensation of water vapor.