# Entropy

#### Ishika

Registered Member
what is randomness or entropy? is it made up of something?

what is randomness or entropy? is it made up of something?
No, it’s a property, not stuff. More specifically it is a statistical property of an ensemble of objects, for example molecules. It’s to do with the number of ways energy can be distributed. The more ways, the greater the entropy.

It’s to do with the number of ways energy can be distributed. The more ways, the greater the entropy.
can you please elaborate on this.... like distribute in???

can you please elaborate on this.... like distribute in???
Distribution among the available "microstates" of the system. These are the individual states it is possible for a molecule, say, to explore in the course of its random thermal motion. You can think of them as all the possible combinations of momentum, position etc that are permitted by quantum mechanics.

There is a connection to the idea of disorder, in that the more of these microstates there are, the more ways there are to arrange the system and the more "random" any given configuration will be.

The basic formula is Bolzmann's equation S =k loge W, in which S is entropy, W is the number of ways to arrange the system, i.e. microstates and k is Boltzmann's constant. (This equation is actually inscribed on his tombstone in Vienna.)

You can get an intuitive idea of what it means by thinking of thermal energy becoming "lost" or "spread out" among all these states. The more that this has occurred, the less the ability of this thermal energy to be organised enough to do mechanical work.

Also, the randomising of energy in this way tends to be irreversible. Once it has become spread out it is hard to collect it together again. Entropy increases in all irreversible thermodynamic processes.

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Laws of Thermodynamics: History
...
(2) Entropy: Origin of the Second Law of Thermodynamics

11:38 min.

"This paper is mostly important for the new terminology in it. Because this is the paper where he renamed the equivalence value to be the shorter term entropy and gave it the letter S for no reason I can tell. ..."

entropy (n.)
https://www.etymonline.com/search?q=entropy

Distribution among the available "microstates" of the system. These are the individual states it is possible for a molecule, say, to explore in the course of its random thermal motion. You can think of them as all the possible combinations of momentum, position etc that are permitted by quantum mechanics.

There is a connection to the idea of disorder, in that the more of these microstates there are, the more ways there are to arrange the system and the more "random" any given configuration will be.

The basic formula is Bolzmann's equation S =k loge W, in which S is entropy, W is the number of ways to arrange the system, i.e. microstates and k is Boltzmann's constant. (This equation is actually inscribed on his tombstone in Vienna.)

You can get an intuitive idea of what it means by thinking of thermal energy becoming "lost" or "spread out" among all these states. The more that this has occurred, the less the ability of this thermal energy to be organised enough to do mechanical work.

Also, the randomising of energy in this way tends to be irreversible. Once it has become spread out it is hard to collect it together again. Entropy increases in all irreversible thermodynamic processes.
Laws of Thermodynamics: History
...
(2) Entropy: Origin of the Second Law of Thermodynamics

11:38 min.

"This paper is mostly important for the new terminology in it. Because this is the paper where he renamed the equivalence value to be the shorter term entropy and gave it the letter S for no reason I can tell. ..."

entropy (n.)
https://www.etymonline.com/search?q=entropy
best explaination i've got till now for entropy, thank you so much. do you have any idea about the most fundamental things like inside quarks its energy so what's this energy made up of?

Laws of Thermodynamics: History
...
(2) Entropy: Origin of the Second Law of Thermodynamics

11:38 min.

"This paper is mostly important for the new terminology in it. Because this is the paper where he renamed the equivalence value to be the shorter term entropy and gave it the letter S for no reason I can tell. ..."

entropy (n.)
https://www.etymonline.com/search?q=entropy

best explaination i've got till now for entropy, thank you so much. do you have any idea about the most fundamental things like inside quarks its energy so what's this energy made up of?
No my degree is in chemistry. The way quarks are bound inside hadrons is not something I know much about. James may know, if he swings by.

do you have any idea about the most fundamental things like inside quarks its energy so what's this energy made up of?
Energy isn't made of anything. Energy is just a number, like an accounting system.

As for quarks, as far as we can tell so far there's nothing inside quarks. They appear to be fundamental particles. They are the constituents of other particles. For instance, a proton consists of two up quarks and one down quark. Quarks are bound together by the strong interaction.

Energy isn't made of anything. Energy is just a number, like an accounting system.

As for quarks, as far as we can tell so far there's nothing inside quarks. They appear to be fundamental particles. They are the constituents of other particles. For instance, a proton consists of two up quarks and one down quark. Quarks are bound together by the strong interaction.
One thing I have never understood about quarks is that the rest mass of a hypothetical free quark is predicted to be much less that than of quarks bound in hadrons. Generally speaking, the "binding energy" due to an attractive force (e.g. an electron bound in an atom by the EM interaction, or a proton or neutron bound in an atomic nucleus by the strong interaction) is the amount by which the energy of the bound state is lower than that of the free state. But in the quark's case it seems the energy is higher when it is bound! Would that not mean that hadrons should fly apart? Is there some activation energy barrier preventing that? Or I have I misunderstood?

exchemist:

The strong force is a strange beast. Unlike gravity or electromagnetic, whose strength decreases with distance, the strength of the strong force increases with distance, at least up to the point where it ceases working at all. I'm not sure this helps to answer your question, though, apart from explaining why hadrons don't fly apart.

There's no such thing as a "free" quark. Suppose we take a meson, made of two quarks, and try to pull the quarks apart. As we pull them apart, the attractive force gets stronger and stronger until there is enough "potential energy" there to create some new quarks out of the vacuum, which then bond with the original quarks to form new composite particles.

I am not a particle physicist, so please take all this with the relevant grain of salt. But as I understand it, in the Standard Model, the strong force is transmitted from quark to quark by "virtual" bosons, called gluons. In a particle like a proton, then, we have not just the three quarks that make up the proton, but also an active "sea" of gluons continuously buzzing around the place. Apparently, the masses of those gluons contribute most of the apparent mass of the proton, rather than the quarks being directly responsible for that.

As for quarks, as far as we can tell so far there's nothing inside quarks. They appear to be fundamental particles. They are the constituents of other particles. For instance, a proton consists of two up quarks and one down quark. Quarks are bound together by the strong interaction.
so you think string theory is not right??

so you think string theory is not right??
I think you need to explain why you say this.

But don't forget string theory is entirely speculative and without observational evidence, as it cannot make observational predictions that could test its validity. Well-grounded people like Peter Woit think it is a case of emperor's new clothes:https://en.wikipedia.org/wiki/Peter_Woit

String theory is not an accepted theory of physics at this point.

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exchemist:

The strong force is a strange beast. Unlike gravity or electromagnetic, whose strength decreases with distance, the strength of the strong force increases with distance, at least up to the point where it ceases working at all. I'm not sure this helps to answer your question, though, apart from explaining why hadrons don't fly apart.

There's no such thing as a "free" quark. Suppose we take a meson, made of two quarks, and try to pull the quarks apart. As we pull them apart, the attractive force gets stronger and stronger until there is enough "potential energy" there to create some new quarks out of the vacuum, which then bond with the original quarks to form new composite particles.

I am not a particle physicist, so please take all this with the relevant grain of salt. But as I understand it, in the Standard Model, the strong force is transmitted from quark to quark by "virtual" bosons, called gluons. In a particle like a proton, then, we have not just the three quarks that make up the proton, but also an active "sea" of gluons continuously buzzing around the place. Apparently, the masses of those gluons contribute most of the apparent mass of the proton, rather than the quarks being directly responsible for that.
Ah yes the increase in force with distance would produce an activation barrier and stop the hadron flying apart.

Free quark seems to be the wrong term. Current quark or valence quark seem to be the terms used, but indeed, the mystery is that most of the mass of a hadron seems to be attributed to the gluon energy rather than the quarks per se.

so you think string theory is not right??
There's no way to tell whether it's right or wrong, yet, as far as I'm aware.

Entropy must be from the Greek word tropos, meaning direction, and I guess the guy had to call it something.

The study of entropy is by no means exhausted; there are clear links to information theory although Gibbs, Maxwell and Boltzmann didn't see it because information science wasn't really there yet. But modern day theorists can point to how the early thinkers were actually thinking about bits of information when considering the motion of 'inert' gas particles and their energy. Or at least, how to represent the information that describes each particle.

And Maxwell-Boltzmann statistics is one kind of distribution, there are also Fermi-Dirac and Bose-Einstein distributions each with their own formulation. Entropy doesn't start and end with random motion in a gas.