2nd principle of termoDynamics

In summary, the second law of thermodynamics states that heat always flows from areas of higher temperature to areas of lower temperature, and this process is not reversible in a closed system. While hot and cold objects can spontaneously appear, these occurrences are rare and unnoticeable. To differentiate between hot and cold objects in a closed system, an outside object must be introduced, but this will not break the isolation of the system. In order to polarize the objects' heats again without opening the system, insulation can be used but it is not a perfect solution and will eventually result in equalization of temperatures. To achieve the original temperature differences in an isolated system, additional energy must be introduced.
  • #1
deda
185
0
The second principle of termodynamics says:
cooler object cannot give away heat spontaneously to warmer one.
I wonder then how do cooler and wormer object appear in a closed system after they have equalized their heat.Or in other words:
Is there a way back <=> Could this phenomenon be reversible in a closed system?

Billioners don't appear in the middle of desert but in the center of society.
 
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  • #2
I'm not sure I understand what you are asking, but heat always flows from areas of higher temp to areas of lower temp. It is not reversible (not even a heat pump qualifies as reversing it).
 
  • #3
I think I get it. He's asking how the second law can be true given that hot and cold things can spontanteously appear. The answer is compound:
1. the second law is statistical, there can be really small variations
2. It only holds for closed systems, but there are technically no closed systems, unless one has the whole universe be your system
3. You might be getting confused with you experience of the world. If you have a piece of metal sitting in a room at room temperature, and touch it, it will feel cold. This is because you are warmer than it and it conducts heat faster than the air, so it draws away your heat faster than the air does, cooling that area slightly below the usual cooling caused by the air, and makes itself warmer.
So pretty much, it is rare and unnoticable that hot and cold things spontaneously occur, so the second law is a really really good rule of thumb.
 
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  • #4
I was aiming more on this:
I have isolated one termo system with cold and warm objects in it.
I brought them in direct contact.
The warm object is giving it's heat to the cool until they become equally warm.
The system preserves all it's heat.
Now if I want to differentiate/distinguish them again I have to insert some 3rd object from outside into the system.
But this will not open the system or it won't break it's isolation cause how much heat the 3rd object is getting from the 1st one that much heat is giving to the 2nd.
In the end my intention is to close the circuit or to get where I started.
Unfortunatelly, this TD principle won't let me do so cause:
The 3rd object has same heat as for the 1st as for the 2nd object which means it will (according to this TD principle) equally worp up(cool down) both objects.
It's same as polarization and neutralization.

How do I polarize the object's heats again without opening the system?
 
  • #5
Originally posted by deda
How do I polarize the object's heats again without opening the system?
Insulation?
 
  • #6
Originally posted by russ_watters
Insulation?

This can slow the process (I know you know this Russ, but this is for the original poster) but there is no perfect insulator, so eventually the temperatures will again equalize.
 
  • #7
If I am understanding your question correctly, you are placing two objects with significant temperature differences(hot and cold) into an insulated container. Then, you bring those two objects together, physically or environmentally, to effect a heat transfer from the hot object to the cold object, eventually equalizing an average temperature of both.
Then, if I understand this, your goal is to separate the objects again, with each object having their original temperature differances.
Can this be done in an isolated system? Of course! Very easily.
Can this be done without the introduction of additional energy? No.
 

What is the 2nd principle of thermodynamics?

The 2nd principle of thermodynamics states that the total entropy of a closed system will always increase over time, or remain constant in ideal cases where the system is in a steady state or undergoing a reversible process.

How does the 2nd principle of thermodynamics relate to energy?

The 2nd principle of thermodynamics is closely related to the concept of energy conservation, as it states that the total energy of a closed system will always decrease over time due to the increase in entropy.

What is the difference between the 1st and 2nd principles of thermodynamics?

The 1st principle of thermodynamics, also known as the law of conservation of energy, states that energy cannot be created or destroyed, only transferred or transformed. The 2nd principle, on the other hand, focuses on the direction and quality of energy transfer and transformation.

Why is the 2nd principle of thermodynamics important for understanding natural systems?

The 2nd principle of thermodynamics is essential for understanding how natural systems, such as ecosystems and the Earth's climate, function and evolve over time. It helps explain why certain processes occur and why others do not, and is a fundamental principle in the study of thermodynamics and energy flow in nature.

What are some real-world applications of the 2nd principle of thermodynamics?

The 2nd principle of thermodynamics has many practical applications, including in the design of engines and refrigeration systems, as well as in the study of weather patterns and climate change. It also plays a role in the production of food and the functioning of biological systems.

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