3 ms·

I've always considered the "increasing disorder" definition of entropy to be a simple analogy that most people can relate to in their everyday lives, not necess

I've always considered the "increasing disorder" definition of entropy to be a simple analogy that most people can relate to in their everyday lives, not necessarily a formal definition. Indeed I would be interested to know if you can even formally define order vs. disorder since it seems to require a subjective observer. For example the universe doesn't consider a glass sitting on the table to be "more ordered" than one that has shattered on the floor. It's just like, our opinion man. But even if you use the order vs. disorder analogy, it's arguable that the universe was close to perfectly ordered right after the big bang. After all it was a pretty smooth and uniform distribution of matter/energy at some point, and that seems more ordered to me than what we have now with all these random clumps of star junk everywhere :) Anyway I like to consider entropy as the amount of usable energy in a system. A whole glass has more energy to release (e.g. by shattering) than a shattered one does. Maybe this is the formal definition of order vs. disorder?

have_faith 8y ago
> Anyway I like to consider entropy as the amount of usable energy in a system. A whole glass has more energy to release (e.g. by shattering) than a shattered one does. Maybe this is the formal definition of order vs. disorder? I think this is correct. Like the sand castle example: there are very few ways the grains can be arranged in order to be a sand castle, but orders of magnitude more ways of being re-arranged into a pile of sand. It could then be said that the sand castle has less entropy, and left to nature, will slowly but surely move towards the predictable high entropy state of being a pile of sand. The reverse is not true. Without work the low entropy state will struggle to reach the orderly state of the sand castle. Someone else mentioned the big bang, which I guess would be the work that created the orderly universe as we see it. But that work was expressed a long time ago and without more work matter will just move to an un-orderly state again.
crimsonalucard 8y ago
"Useable energy" is vague word and thus not a good description. There is a quantitative definition of entropy but it is based in a way off of "opinion". Given a system and its laws look at all possible final states. Then group the states according to an arbitrary "rule" For example: the state of white marbles and black marbles in a jar. What is the number of possible arrangements of all black marbles to be arranged on the left side of the jar and all white marbles to be arranged on the right? This is an arbitrary "rule." It's a big number but that number is much lower than every other possible arrangement. From these quantities you can derive an entropy value. However you will note that it depends on that "rule" you define. I could point to the state of marbles in the jar after I shake it and call that my "rule" and it makes that arbitrary state one of low entropy. I could point to any arbitrary state and do this and thus any specific state is one of low entropy. It's a complex definition and it encompasses "opinion" and "choice." The definition of entropy allows for an numerical value to be derived based off of your "opinion." In Boltzmann's definition, entropy is a measure of the number of possible microscopic states (or microstates) of a system in thermodynamic equilibrium, consistent with its macroscopic thermodynamic properties (or macrostate). The macrostate is basically what I defined above as "rules" and what you defined as "opinion."

have_faith 8y ago

> Anyway I like to consider entropy as the amount of usable energy in a system. A whole glass has more energy to release (e.g. by shattering) than a shattered one does. Maybe this is the formal definition of order vs. disorder? I think this is correct. Like the sand castle example: there are very few ways the grains can be arranged in order to be a sand castle, but orders of magnitude more ways of being re-arranged into a pile of sand. It could then be said that the sand castle has less entropy, and left to nature, will slowly but surely move towards the predictable high entropy state of being a pile of sand. The reverse is not true. Without work the low entropy state will struggle to reach the orderly state of the sand castle. Someone else mentioned the big bang, which I guess would be the work that created the orderly universe as we see it. But that work was expressed a long time ago and without more work matter will just move to an un-orderly state again.

crimsonalucard 8y ago

"Useable energy" is vague word and thus not a good description. There is a quantitative definition of entropy but it is based in a way off of "opinion". Given a system and its laws look at all possible final states. Then group the states according to an arbitrary "rule" For example: the state of white marbles and black marbles in a jar. What is the number of possible arrangements of all black marbles to be arranged on the left side of the jar and all white marbles to be arranged on the right? This is an arbitrary "rule." It's a big number but that number is much lower than every other possible arrangement. From these quantities you can derive an entropy value. However you will note that it depends on that "rule" you define. I could point to the state of marbles in the jar after I shake it and call that my "rule" and it makes that arbitrary state one of low entropy. I could point to any arbitrary state and do this and thus any specific state is one of low entropy. It's a complex definition and it encompasses "opinion" and "choice." The definition of entropy allows for an numerical value to be derived based off of your "opinion." In Boltzmann's definition, entropy is a measure of the number of possible microscopic states (or microstates) of a system in thermodynamic equilibrium, consistent with its macroscopic thermodynamic properties (or macrostate). The macrostate is basically what I defined above as "rules" and what you defined as "opinion."