Final answer:
Condensation of water vapor causes the fog that you can see when you breathe out on a cold winter morning.
Step-by-step explanation:
When you breathe out on a cold winter morning, you can see your breath because of a phenomenon called condensation. The warm air you exhale contains a lot of water vapor, which quickly cools when it meets the colder outside air. This causes the water vapor to condense into tiny droplets of liquid water, creating the fog that you can see.
Thus, condensation is the process in which a gas or vapor transforms into a liquid. This occurs when warm air cools down, leading to a decrease in the air's capacity to hold water vapor. The water molecules then gather and form liquid droplets, resulting in phenomena like dew, fog, or cloud formation.