3 ms·
Entropy is not disorder. It is S ~ log #{microstates} For hn readers, microstates you can think of as a configuration of a system, so its counting number of c
by foxes 7y ago
Entropy is not disorder. It is
S ~ log #{microstates}
For hn readers, microstates you can think of as a configuration of a system, so its counting number of configurations. Disorder is not well defined. Stop using the word disorder with entropy. A bunch of more complicated elements have more configurations than just pure H.
- BLKNSLVR 7y agoMy interpretation is that "order" and "disorder" are subjective. One person's order is another's disorder. For example, my wife and I have differing tolerances of "order" as it pertains to the tidiness of a room. That may seem far separated from the topic at hand, but if a thing is able to be somewhere, then it's purely subjective as to whether it's the right place, ie. ordered. There's a time component to it as well, I might have a bunch of in-progress things laying around, but that's the correct place for those things for the current moment, for me. In parallel, however, it's most definitely the incorrect place, at all times, according to my better half. Potential Configurations = n Configurations considered "order" by me: x Configurations considered "order" by milady: 1 Configurations considered "order" by the universe: 0 Configurations considered "order" by the universe at this point in space and time: 1 That which is, is order. That which isn't, is not. Reminds me of this scene from Hi Fidelity: Dick: It guess it looks as if you're reorganizing your records. What is this though? Chronological? Rob: No... Dick: Not alphabetical... Rob: Nope. Dick: What? Rob: Autobiographical. Dick: No way.
- spectramax 7y agoThis may be correct but its useless to make any engineering sense out of it. For engineering and practical intuition, use the following definition that we used at an Ivy-league college in US: https://en.wikipedia.org/wiki/Entropy_(energy_dispersal) https://en.wikipedia.org/wiki/Entropy_(energy_dispersal) Quoting the article: > Even though courses emphasised microstates and energy levels, most students could not get beyond simplistic notions of randomness or disorder. Many of those who learned by practising calculations did not understand well the intrinsic meanings of equations, and there was a need for qualitative explanations of thermodynamic relationships.
- deleted 7y ago[deleted]
- NotSammyHagar 7y agoTrust the formula you used at an ivy league college? Come on, that's a laughable call to some unknown expert! I don't care if your ideas come from an ivy league college. I care about the ideas and their quality. I distrust people that think because something came from a prestigious school I should trust them.
- spectramax 7y agoThat's extreme and I am sorry you feel that way. I didn't realize that mentioning Ivy-League college would be seen as ego-inflating thing. I simply wanted to say that it was used in a college level class. I definitely agree, truth matters and not the source.
- NotSammyHagar 7y agoThanks for your civilized reply to my semi-rant ;-)
- foxes 7y agoI don't mind a qualitative explanation for casual discussion, but it still must be morally correct. I think "configurations" is a pretty intuitive concept. >imagine all the ways you can stack lego together.
- ajkjk 7y agoIt's the physicist's definition, for whose purposes it is quite useful. And yeah, the physics students at your ivy league school learned H = log|microstates| also. Anyway, entropy as a count of microstates has to be packaged with a couple of additional ideas to give rise to the concept as used in chemistry/etc. First, that the microstates are randomly explored by the system, and second, that the number of microstates is so mind-boggling exponentially huge that the most common ones will be the only ones you ever see in practice.
- 7y ago
- tingletech 7y agoIs that the same as H'=-\sum _{i=1}^{R}p_{i}\ln p_{i} as per https://en.wikipedia.org/wiki/Diversity_index#Shannon_index https://en.wikipedia.org/wiki/Diversity_index#Shannon_index With a log base e for nits (or natural digits) and a log base 2 for bits (or binary digits) as per _a mathematical theory of communication_ (Shannon 1948)?
- c1ccccc1 7y agoNot quite. The formula you gave is the more general one, the previous one assumes that all microstates are equally likely. Given that assumption they are equivalent though.
- tingletech 7y agohow does one read "log #{microstates}"? Is it simply "log of the number of microstates"?
- foxes 7y agoYes.
- n4r9 7y agoThere's a quote by von Neumann advising Shannon on what to name his measure of uncertainty: > You should call it entropy, for two reasons. In the first place your uncertainty function has been used in statistical mechanics under that name, so it already has a name. In the second place, and more important, nobody knows what entropy really is, so in a debate you will always have the advantage.
- elevenoh 7y agoOr 'the number of possible microstates (internal configurations) that amount to a given macrostate'