Why does a cold glass get wet outside?
The water can come from the room’s air.
The short answer
Air contains water vapour, an invisible gas. If air next to the glass cools enough, some vapour becomes liquid on the surface. This change, condensation, forms the little outside droplets.
An example to make sense of it
An intact glass of iced water can become wet outside without water passing through the glass: humid air supplies the water that condenses.
How to answer
Choose the conclusion best supported by the facts and press Check. You can revise an incorrect answer and use help whenever you wish.
Preparing the case…