12-3-second-law-of-thermodynamics-entropy_summary

The second law of thermodynamics, when applied to thermodynamics, states that the entropy (a measure of system disorder and the unavailable energy to do work, increasing as energy dispersal increases) of a thermodynamic system in isolated conditions always increases over the course of any spontaneous process. This means: * Entropy always tends to increase—never decreases * Heat spontaneously spreads from higher temperature object to a lower one with the hotter object, not the colder increasing, experiencing less entropy gain than the colder one having a greater entropy gain increasing, leading to a gain in overall entropy for the systems involved * Spontaneous processes in thermodynamics do not lead towards orderliness and/or decrease in entropy--an example of this may be a gas released randomly in a vacuum chamber gradually filling the entire space where it was released rather returning to the point of where it was initially released unaided * Local examples of entropy decrease, whether from work being done -such as gathering and compiling iron ore into structuring steel- still tend to result in overall temperature increases, demonstrating non-violation of thermodynamic principles, resulting from the work expended ultimately creating more disorder elsewhere, including Earth.