I don’t understand how atoms that are in the “negative tempretures” have 0 entropy while being insanely hot. I also dont get how negative temperatures are hotter than infinity if (planck’s temperature forbids this; dont really know if it does). Please explain!
In: Physics
There’s two ways to define temperature:
* How much the molecules of a substance are moving, on average.
* How much the entropy, or difficulty-to-predict, of a substance is affected by adding energy.
The first is the day-to-day usage. Molecules moving is heat energy; the average amount of movement in a substance is that substance’s temperature.
The second usage is used by physicists. Most of the time, they’re the same; as you add heat to a substance, its molecules move more and become harder to predict, thus entropy increases. That’s a positive temperature. A negative temperature would be the opposite situation – adding energy reduces chaos, makes things easier to predict.
In some very strange and rare substances, adding heat can *reduce* the chaos in that substance. For instance, atoms spin; in certain circumstances, the direction the atoms are spinning will be random, fully chaotic, max entropy. But by adding energy to the system, we can actually making more and more of the atoms spin in the same direction. Thus, adding energy is decreasing entropy – which means that the temperature of the substance is negative.
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