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?
In: 594
No, but yes, but no.
No, because all forms of heat transfer depend on the difference in temperature between two materials. If you have a hot rock at 60C and a cold cup of water at 5C and you put the rock in the water, it will warm the water up and the water will cool the rock down until they’re both at exact same temperature, somewhere in the middle.
If two objects are at the same temperature, no heat transfer can occur between them.
Yes though, because there’s some exception due to the “latent heat of vaporization”, particularly of water. When water evaporates, it needs extra energy, which it *loves* to steal from its surroundings, particularly the things its in contact with. This is how sweating works, and it’s why sweating can help you cool down even when the air is hotter than your skin. The water evaporates into the air, and because of its “latent heat of vaporization”, it steals a bit of energy from your skin, cooling you down. This only works if the relative humidity is below 100%. This can cause a object that’s wet to get colder than its surroundings, but it’ll only last until the water is done evaporating. This is called the evaporative cooling effect. On a small scale, you can find what are often called “swamp coolers” which blow air over a water soaked surface to cool the air. These drive up the humidity while cooling though, and can cause a higher humidity in the space making it feel even *more* uncomfortable in the long run. They also have a nasty tendency to get moldy. Hence the name “swamp cooler”. On a large scale, industrial cooling towers use evaporative cooling, and are used to cool water for industrial processes, and can lower the temperature of the water to below the atmospheric temperature, so long as it’s not 100% humid out.
But practically, and in your scenario, no.
The evaporative cooling effect wouldn’t have much effect below freezing because any standing water would freeze anyways. Ice and snow can still sublimate and steal energy, but that is WAY slower than evaporation, and would have a completely negligible effect.
One object can *feel* colder than another, but that’s related to how quickly they transfer heat away from you. You can have a piece of wood and piece of aluminum at 10C and touch them. The aluminum will *feel* much colder. Your skin (36C) has the same temperature difference with each, but aluminum conducts heat much better than wood, so it’s able to take that energy from your skin much faster. Fun fact, your skin doesn’t feel temperature, it feels *heat transfer*. That’s why when you come inside with cold numb hands, you can run them under cool tap water and it will still feel burning hot. Your fingers are colder than the water, and you’re feeling that fast heat transfer into your body and it feels the same as burning your fingers.
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