Best explanation for 1-way entropy?

In summary, the conversation discusses the concept of entropy and the law of increasing entropy. While some may see it as a general rule, it is actually a law due to the overwhelming probability of systems tending towards states of increased entropy. This is supported by the fact that, statistically, systems have a higher chance of reaching equilibrium states with increased entropy over a very long period of time. The conversation participants also thank each other for their input and acknowledge the usefulness of Physics Forums for discussing complex concepts.
  • #1
dydxforsn
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What is the best explanation for why entropy must increase BY LAW. I can see it as being a good general rule, but I don't quite see why it's law, especially when you consider a micro-state explanation of entropy. What is the best argument for the law of increasing entropy?
 
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  • #2
My thermo is a bit rough, but the entropy of a system always increasing actually means the system, with overwhelming probability, tends towards states of increased entropy. You CAN see a system go from higher entropy to lower entry, but the probability is vanishingly small.
 
  • #3
Statistically, what Peng said is right in a short time scale. When you consider a sufficiently huge amount of time (and this is very, very huge amount of time, many times the age of our universe), every equilibrium state would be accessed and the total entropy variation would be null.
 
  • #4
Thank you both for the reply! I was thinking along those lines, but I wasn't sure at all. Physics Forums is such a good tool for this kind of thing..
 
  • #5


I would like to provide a clear and accurate explanation for the concept of entropy and the law of increasing entropy.

Entropy is a measure of the disorder or randomness in a system. It is a fundamental concept in thermodynamics, which is the study of energy and its transformations. The second law of thermodynamics states that the total entropy of an isolated system will always increase over time.

One way to understand this law is through the concept of probability. In any system, there are a vast number of possible microstates (i.e. the specific arrangement of particles or molecules) that can lead to the same macrostate (i.e. the overall state of the system). However, there are significantly fewer microstates that correspond to a highly ordered or low-entropy macrostate, compared to those that correspond to a disordered or high-entropy macrostate. This means that it is much more likely for a system to move towards a high-entropy state, leading to an overall increase in entropy over time.

Another way to understand the law of increasing entropy is through the concept of energy dispersal. In any system, energy will naturally flow from areas of high concentration to areas of low concentration, until it is evenly distributed throughout the system. This process leads to an increase in entropy, as the energy becomes more dispersed and less organized.

The law of increasing entropy is considered a fundamental law of nature because it is based on well-established principles of thermodynamics and has been observed and confirmed in numerous experiments. It applies to all systems, from the microscopic level of individual particles to the macroscopic level of the entire universe.

In summary, the best explanation for the law of increasing entropy is that it is a fundamental law of nature that is based on the principles of thermodynamics and has been observed in countless systems. It is a necessary consequence of the probabilistic nature of particles and the tendency for energy to disperse and become more evenly distributed.
 

1. What is 1-way entropy?

1-way entropy is a measure of the uncertainty or randomness associated with a single event. It quantifies the amount of information needed to describe the outcome of an event with a probability of 1 (certainty).

2. How is 1-way entropy calculated?

The formula for 1-way entropy is H = -∑p(x)log2p(x), where p(x) represents the probability of each possible outcome of the event. This formula takes into account the likelihood of each outcome and assigns a higher value to events with lower probability, reflecting the higher amount of information needed to describe them.

3. What is the significance of 1-way entropy in science?

1-way entropy is a fundamental concept in information theory and has important applications in various fields of science, including physics, biology, and computer science. It allows us to quantify the amount of uncertainty in a system and understand the degree of randomness present in a particular event or process.

4. How does 1-way entropy relate to thermodynamics?

In thermodynamics, 1-way entropy is often referred to as Boltzmann entropy and is closely related to the concept of disorder or randomness in a system. It is used to explain the direction of heat flow and the tendency of systems to move towards a state of higher disorder.

5. Can 1-way entropy be reduced or eliminated?

No, 1-way entropy is a fundamental property of systems and cannot be reduced or eliminated. However, it can be transferred or converted into other forms of energy, such as heat or work. In some cases, entropy can also be decreased locally at the expense of increasing it elsewhere.

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