Say you store a vehicle outside all winter, if there was an usually cold week, say -20 degrees Fahrenheit for example, is it possible for the car to be colder than the -20 since it sat weeks prior to the -20 temps?
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No, any system tries to reach a balance where everything is the same temperature, that said it might feel colder or hotter because of the material it’s made out of, metal tends to feel much colder than air at the same low temperature
No (unless you cool them). But they can FEEL colder.
Some materials (rocks, metals, water) have a large capacity to absorb heat. And, in the case of metals, transmit it really fast as well. That means if you touch them, they will seep the heat out of your body without noticeable change in their own temperature. They feel “cold”.
Other materials (like most organics, most powders, foams, air) have a lower heat capacity or heat transfer so low (they’re insulating) that it makes no difference. When you touch them, the heat of your hand quickly brings their surface temperature close to your skin temperature. They don’t feel “cold”. Some materials insulate so strongly (say, knitted wool) that so little heat escapes that they feel outright warm.
Yes, if it can radiate more heat than it absorbs, which depends on the properties of the car’s surface. This effect/application is called radiative cooling. It’s more common in buildings than in cars.
More info: https://en.wikipedia.org/wiki/Passive_daytime_radiative_cooling
First of all, heat takes some time to reach equilibrium, but not weeks in the case of a car. Second, if the temperature surrounding the car is -20, the car will try to reach -20, not any colder temperature. It could perhaps be colder than -20 only if it was even colder before that. EDIT: but see u/ShelfordPrefect’s response comment.
If the object can evaporate (ie is moist or wet) then it can become colder than the ambient air due to evaporation. This only works if the air is lower than 100% humidity.
This concept is captured by wet bulb and dry bulb temperatures which are sometimes reported.
They don’t. All objects are at almost equilibrium in term of termperature in the same space. They just feel different because of their thermal conductivity.
Yes.
Clear night, radiation to the vault of the sky (a close approximation of a black body that absorbs all radiation) cooling the surface. Metal has a high emissivity and is most prone to it. It causes condensation (which can freeze) on the inside of metal roofs on buildings.
It can also cause black ice (frozen condensation/dew) on tarmac roads when the air temperature is above freezing.
Ther time ouside isn’t very relevant, the sheet metal doesn’t have enough mass to make much difference.
Anything with a high specific heat capacity like a body of water will generally not correspond to its ambient temp i.e. a pool remains really cold well into the spring and early summer.
No, heat always moves from the hottest thing to the coldest one until they reach equilibrium. Even if the car was left in the cold for a very long time if the environment was -20F once every part of it reaches that temperature it stops losing energy, what could happen is that once the ambient temperature starts to rise the car could take a while to catch up
In general, no. Other posters have mentioned a few examples where it’s possible, freezing, or objects with high thermal mass subjected to more cooling previously. There are some extreme examples used by engineers and physicists to get items colder than their surroundings – gas expansion in fridges / freezers, peltier effect, and in extreme cases, laser cooling.
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