Geocentric Science

Once the water is turned on in the shower, the hot, moisture-rich water will begin to evaporate warming the bathroom. However, the bathroom mirror still remains cold. When the warm, moist air touches the cold bathroom mirror condensation will occur (the mirror becomes “foggy”). The air in the bathroom is cooled to its dew point (saturation and condensation occurs).

Another example is condensation on a cold glass of water on a hot summer day. The glass surface of the cup of water provides a perfect boundary for the hot air and the cold water to meet and for the air temperature to cool to its dew point temperature.