Why Does Glass Fog Up When You Pour Cold Water In It?
What It Is
Fogging on a glass is the formation of tiny water droplets on the outside surface.
How It Works
Air always contains some moisture. When cold water is poured into a glass, the glass cools quickly. The warm air touching the cold surface cools down, and the moisture in that air turns into liquid droplets.
Why It Happens
This fogging occurs because of temperature differences:
- Cold water lowers the glass temperature
- Warm air contacts the cold surface
- Water vapor in the air condenses into droplets
Common Examples
- Cold drinks sweating on a table
- Windows fogging on humid days
- Mirrors fogging after a shower
What to Know Next
The fogging stops once the glass warms up or the surrounding air becomes drier.
Simple Cautions
Fogging is normal and does not mean the glass is leaking or cracked.
Closing Summary
Glass fogs up when cold water cools its surface, causing moisture in the warm air to condense into visible droplets.
