take more time for a hot cup of coffee to reach room temperture than a
ice coffee to reach the same point? Going back to physics 101, any
change is actually a change in energy. Less energy means colder. So
the hot coffee is giving off energy to the system around it. I guess
this means that the real question is, how easily does air accept or
give energy? If air takes in energy faster than it gives off the hot
coffee would lose energy faster than the cold coffee would gain it,
meaning hot Joe cools faster. I didn't even touch the ice cubes in
iced coffee. I got to class to quickly. If you know the answer let me
know. I'm pretty sure my brother might.
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The second law of thermodynamics (simplified significantly) states that heat will flow from hot to cold. Cooling something down doesn't require any energy input, and will more or less happen spontaneously if the surrounding environment is warmer. In order to heat something you have to input energy. So generally speaking, your hot coffee will reach room temp more easily than your iced coffee will. Determining an actual rate requires a little more math, but I think its safe to assume that your hot coffee will get cold before your iced coffee gets hot. I'm glad I knew the answer after you called me out like that.
Sorry to take up so much space, but I forgot the key point. The temperature difference between the liquid and the air is the most significant variable. Since the hot coffee is much warmer than the air and the iced coffee is only slightly cooler the rate of cooling is faster. As you approach room temp the difference will decrease, but at that point it wouldn't be noticeable. That's what I get for being cocky.
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