Why Does My Mirror Fog Up When I Take a Shower?

  • Thread starter Peter G.
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In summary, when we take a hot shower, the steam from the hot water combines with the cooler air in the bathroom and forms a hot and humid environment. When this hot and humid air comes into contact with the cooler surface of the mirror, it cannot hold as much water and condenses, depositing water onto the mirror. This is due to the dew point, which is the temperature at which water condenses out of the air and depends on the humidity.
  • #1
Peter G.
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When we take a hot shower, the mirrors go all misty/foggy:

This is due to condensation, but how does this happen?

Is it the hot water from the shower heating up the air together with the water from the shower evaporating into the air forming a hot and humid environment. When this hot and humid air touches the colder glass it can't hold as much water and therefore, condenses, depositing water on the mirror?

Thanks
 
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  • #2
Peter G. said:
When this hot and humid air touches the colder glass it can't hold as much water and therefore, condenses, depositing water on the mirror?
Precisely.
There is a temperature - called the dew point - at which water will condense out of the air - which depends on the humidity
 
  • #3
Ok, cool! Thanks NobodySpecial!
 

Related to Why Does My Mirror Fog Up When I Take a Shower?

1. Why does my mirror fog up when I take a shower?

The fog on your mirror is caused by the difference in temperature and humidity between the bathroom and the mirror's surface. When you take a hot shower, the warm, moist air comes into contact with the cool mirror, causing the water vapor to condense and form droplets on the surface.

2. Can I prevent my mirror from fogging up during a shower?

Yes, there are a few ways to prevent your mirror from fogging up during a shower. One method is to rub a small amount of shaving cream or dish soap on the mirror and then wipe it off with a clean cloth. This creates a thin film that prevents the water vapor from condensing on the mirror's surface. Another option is to install a heated mirror, which uses a small heating element to keep the mirror's surface warm and prevent fogging.

3. Why does the fog on my mirror eventually disappear?

The fog on your mirror will eventually disappear because the air in the bathroom becomes more humid as the shower continues. This increase in humidity means that the air can hold more water vapor, causing the fog on the mirror to evaporate.

4. Does the type of mirror affect how much it fogs up?

Yes, the type of mirror can affect how much it fogs up. Mirrors with a thin, non-reflective coating on the back are more likely to fog up because the coating prevents heat from transferring to the mirror's surface. Mirrors without this coating, such as antique mirrors, are less likely to fog up because they allow more heat to transfer to the surface.

5. Can I use a hairdryer to remove the fog from my mirror?

Yes, you can use a hairdryer to remove the fog from your mirror. Set the hairdryer to a low heat setting and hold it a few inches away from the mirror's surface. Move the hairdryer back and forth until the fog disappears. Be careful not to hold the hairdryer too close to the mirror, as the heat could cause the mirror to crack or shatter.

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