entropic two-step

[Brainee]

What is entropic two-step?

[exchemist]

7 minutes ago, Brainee said:

What is entropic two-step?

No idea. Can you give some context, please? 

[iNow]

5 hours ago, Brainee said:

What is entropic two-step?

It’s the name of the dance we do when my favorite band, The Quantum Mechanics, are playing down at the Fizzy Physics entertainment hall. The place is so disordered, though, it really saps our energy as we heat over time.

[sethoflagos]

10 hours ago, exchemist said:

No idea. Can you give some context, please? 

It's one of Brian Greene's catchphrases. It seems like a catch-all for all processes similar to the crystallisation of a low entropy solid phase out of a higher energy solution. It crops up about a minute or so into this. 

 

[exchemist]

9 minutes ago, sethoflagos said:

It's one of Brian Greene's catchphrases. It seems like a catch-all for all processes similar to the crystallisation of a low entropy solid phase out of a higher energy solution. It crops up about a minute or so into this. 

 

Aha. Thanks. So it's basically the riposte one gives to some fool of a creationist intoning, in a singsong voice, that "order cannot come from disorder". 😄 

I'm not sure that calling it a "two step" is a very helpful label, but the idea is simple enough, certainly.  

[sethoflagos]

2 minutes ago, exchemist said:

Aha. Thanks. So it's basically the riposte one gives to some fool of a creationist intoning, in a singsong voice, that "order cannot come from disorder". 😄 

I'm not sure that calling it a "two step" is a very helpful label, but the idea is simple enough, certainly.  

Me neither. Too closely associated in my mind with the Aztec two-step to give the right picture.

But we should have a word for it really. In my own internal dialogues I call them 'condensations', but this is the first time I've communicated that to anyone. One person's mental picture doesn't necessarily work for others. 

11 hours ago, Brainee said:

What is entropic two-step?

This ifdea covers so many different processes and interactions that it's very difficuly to give a general answer that covers everything without quoting most of a thermodynamics textbook. So simple examples are probably the nest way to go.

If we take too simplistic a view of entropy, many of the things we see happening around us don't seem to make sense.

Take for example a glass jar of muddy water. The silt particles are all over the place so the entropy is relatively high. 

If we leave it to stand for a few hours most of the particles will settle to the bottom of the jar leaving the water much clearer. This is a lower entropy state and appears at first glance to contradict the 2nd Law of thermodynamics. We've produced 'order' out of 'chaos'.

It only makes sense when you realise that as the silt particles settled, they created a bit of heat due to friction. That heat was lost to the surroundings, which raised the entropy of the surroundings by at least as much entropy as was lost from the contents of the jar. So the world starts making sense again.

Understanding such simple pictures help you to understand how much more complex processes like photosysnthesis can build trees for example out of a few simple molecules and sunlight.