2007-11-07 06:07:55 · 9 answers · asked by fastfredy0 2 in Science & Mathematics ➔ Weather
I'm amazed at how many COMPLETELY wrong answers there are to this question. It has nothing to with with frost or dew "settling" down from the air onto the car--that is nonsense. The air under the carport has the same moisture and can make just as much frost or dew as the air outside, if the car were cold enough. The car parked under the carport is NOT cold enough for the frost to form on it because it has the relatively warm carport ceiling radiating infrared radiation down on top of it, whereas the car out in the open has the relatively cool sky radiating down on it, hence the difference in the car's temperature and its ability to chill nearby air down to the dewpoint.
It also doesn't have to do with the car radiating away less heat when it's under the carport, since its temperature will be higher and it will in fact radiate away more heat, from Stefan's Law.
2007-11-07 11:18:10 · answer #1 · answered by pegminer 7 · 1⤊ 1⤋
Well, actually. The "skin" temperature of the vehicle is cooler on the car that is in the open and exposed to the entire sky.
The car that is parked under a car port (roof with no sides) will have some of the infrared radiation that it emits scattered back to the vehicle that is under it. Thus the car completely exposed to the clear sky will radiate out into space and have a colder temperature on the surface. The colder temperature will cool the air next to the surface of the car more. The air will be forced to lose more water vapor to the air to maintain equilibrium with respect to ice (frost) to maintain 100 percent RH since it will not want to go above 100 percent. Also, the equilibrium with respect to ice is less than that of water so the water vapor will have a tendency to attract more water vapor from the air than dew or a puddle of water would.
I know I sort of got a little technical but I hope you can understand it.
One of the neat things to try is to obtain an infrared thermometer that measures temperature by measuring an objects infrared radiation. This would show the differences in "skin" temperature of an object. Sort of a fun thing to play around with on a clear calm night to see what loses temperature the fastest. (At night white colored objects are black in infrared and lose temperature faster than the same material that is a darker color which is sort of backwards from absorbing solar radiation and explains one of the reasons why it gets so cold on a clear night after a fresh snow. )
2007-11-07 07:37:56 · answer #2 · answered by Water 7 · 0⤊ 1⤋
Because the frost is from dew and moisture in the air. Since the car is under a roof, less dew falls on it making it less frosty in the morning.
2007-11-07 06:21:40 · answer #3 · answered by Anonymous · 1⤊ 1⤋
because the frost falls from the sky at night and makes a sort of a layer over the ground but if it is covered by something then there wont be any frost on it unless there is heavy winds
2007-11-07 06:22:06 · answer #4 · answered by Anonymous · 0⤊ 1⤋
Because the moisture required to create frost settles from the atmosphere as it cools. The car is sheltered from above.
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2007-11-07 06:16:03 · answer #5 · answered by Anonymous · 3⤊ 1⤋
frost comes from slight falling percipatation in the air, slowly wetting and frezzing to the windsheild, cars under cover do not aquire the wetness
2007-11-07 06:16:06 · answer #6 · answered by the_real_eaglesfan03 3 · 2⤊ 1⤋
the roof gets the radiation cooling, protecting the car from it.
Car is protected from radiation cooling
2007-11-07 08:16:24 · answer #7 · answered by rosie recipe 7 · 0⤊ 0⤋
Probably has to do with the houses temperature (I'm assuming this is an attatched car port).
2007-11-07 06:22:20 · answer #8 · answered by Anonymous · 0⤊ 2⤋
Yes! No explanation... my response is based on personal experience.
2007-11-07 06:16:40 · answer #9 · answered by Anonymous · 0⤊ 0⤋