[Q] Wing Mirrors

[paigetheoracle]

Why don't wing mirrors freeze when car windows do?

[freeztar]

Mine freeze.

 

Though, I have noticed that they seem to freeze less than my windshield or side windows. I'm not sure exactly why this happens. Perhaps someone else can explain.

[Boerseun]

Wing mirrors are in the open, their fronts and backs cool at the same rate.

 

Windshields, however, have enclosed air behind them, the interior of the vehicle.

 

So, what happens, is that the air inside the car cools down slower than the open air outside the car, and this, of course, creates condensation on the outside of the windshield. When it cools down further, the condensed droplets turn to ice. There is no reason for condensation to form on the wing mirrors though, because the air in front of them and behind them cools at the same rate.

 

As an experiment, leave your car outside with all windows open, so the windshield is faced with the same temperature air from both sides as it cools down. No condensation will form, hence no ice.

[Boerseun]

When your wing mirrors do freeze up, however, it's likely because of the mounting around and behind them retaining some heat. This should cause the same effect as the enclosed air inside the vehicle causing ice on the windshield.

 

I suppose there's no definite answer like "Wing mirrors will not ice up", because they clearly do in Freezy's case. I guess the answer lies in the design and material the mirrors are constucted from, and how much heat will be retained by the design/material combination in each individual case.

[freeztar]

I think you've nailed the question B. I also think that your guesswork regarding the insulating properties of tight fitting mirror mounts might well have something to do with wing miirrors freezing. This is probably especially true with motor driven (auto adjusting) mirrors (such as mine).