# Tag Info

### Why isn't the free expansion of a gas in an adiabatic container isentropic?

The free expansion isn’t reversible because the gas flows down a pressure gradient (that arises when you remove the piston). Any energy flow down a gradient generates entropy. In contrast, during the (...
• 15.6k

### Why isn't the free expansion of a gas in an adiabatic container isentropic?

If you expand a gas adiabatically using a piston, the process is isoentropic. An adiabatic process is not isentropic unless it is also reversible. To be reversible, it must be carried out quasi ...
• 58.5k
Accepted

### Generation of order on the Earth

Not sure what sort of simulation or model you are looking for. Our proximity to the Sun creates a temperature and energy difference across the surface of the the Earth that is essential to almost all ...
• 36.9k

### Fundaments of thermodynamics and separating entropy

"Also, from this formalism, we can deduce that entropy production is generated either by work/volume variation or by internal entropy flow in compound system, is this generally true?" No. ...
• 28.8k

### Fundaments of thermodynamics and separating entropy

Question 1 If all of this works, why is it never taught in this way? Thermodynamics can be taught and understood in many different ways. If your way makes sense to you, use it. Personally I would not ...
• 1,361
Accepted

• 15.6k

### Why isn't the free expansion of a gas in an adiabatic container isentropic?

There are only two mechanisms by which the entropy of a closed system can change: By heat transfer between the surroundings and the system at the location and temperature of the boundary between the ...
• 28.8k

### Fundaments of thermodynamics and separating entropy

we can deduce that entropy production is generated either by work/volume variation or by internal entropy flow in compound system, is this generally true? The following line of thinking could be ...
• 15.6k

### Is the second law of thermodynamics a "no-go" theorem?

I was writing this post for a question that was closed as duplicate before I finished, so I put it here because the answers here do not contain my point. One has to understand what "laws" ...
• 225k
1 vote

### Consequence of entropy increasing with time

I suspect entropy is a trickier concept that someone might think, since it measures way more than just disorder of a system. From the microscopic point of view, it's strongly related to the possible ...
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1 vote

• 1,361
1 vote

### Fundaments of thermodynamics and separating entropy

If all of this works, why is it never taught in this way? ... The three most common paradigms to teach thermodynamics are laws, postulates, and statistical mechanics. They have withstood tests on ...
• 2,526
1 vote

### Is the second law of thermodynamics a "no-go" theorem?

There is an argument that can be made that adding the additional but intrinsic to science restriction of limiting physical phenomenon to those that can be empirically attested to renders the obeying ...

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