Traditional Culture Encyclopedia - Hotel franchise - There is a circle in the mirror without water mist. What happened?

There is a circle in the mirror without water mist. What happened?

There is a heat source.

1 first of all, the mirror will be foggy, because the hot water vapor in the bath touches the surface of the mirror and condenses into small water droplets when it is cold.

2. Secondly, because water molecules liquefy when they meet the mirror, it is because the mirror is cold, and the temperature difference of the air will lead to the exothermic process, thus the water vapor liquefies.

3. Finally, if the mirror is heated to a temperature greater than or equal to the air temperature, it will not lead to the exothermic process of water vapor and will not form fog.