Decrease in entropy and 2nd Law of Thermodynamics

In summary, the conversation discusses the concept of entropy in a closed system, particularly when a warm object is placed in a refrigerator. It is explained that while the refrigerator may decrease the entropy of the object inside, the overall entropy of the isolated system (the room enclosing the refrigerator) still increases due to the heat generated by the refrigerator's cooling process. It is also noted that the efficiency of the refrigerator must be considered in this process. The conversation ends with a question about the educational backgrounds of the participants.
  • #1
imy786
322
0
General entrpy question from a book- (not a homework quesiton):

When a room temp object is placed in a refrigerator, heat flows out of object and its entropy decreases. Indeed, the refrigerator may be said to be a device for sucking entopy out of warm objects. How can such a decrease in entropy be consistent with the 2nd law of thermodynamics?

2nd law of thermodynamics:
The total entropy of an isolated system cannot decrase, it may increase.
 
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  • #2
Your refer' is pumping entropy into your kitchen...

Entropy in a closed system -- one where no energy crosses the boundary between system and not-system -- always increases. While the door of the refrigerator may be closed, it's not a closed system because heat is being transferred from inside to outside via the condenser you'll find someplace on the back.
 
  • #3
The total entropy of an isolated system cannot decrease.

The fridge is not an isolated system by itself, it gives off heat so your system would (roughly) be the room enclosing the refrigerator. The heat the refrigerator is giving off generates more entropy than the cooling effect of the stuff in the fridge has decreasing entropy. This is because you need to consider the efficiency of the fridge. A fridge is not 100% efficient, nor can it ever be.
 
  • #4
Thank you so much schip666! and Feldoh.

if you don't mind me asking are you both graduates in Physics or lecturers or other please do let me know. You may PM me if you want.

Thanks
 
  • #5
I have a degree in Aesthetic Studies...
 

Related to Decrease in entropy and 2nd Law of Thermodynamics

What is entropy and how does it relate to the 2nd Law of Thermodynamics?

Entropy is a measure of the disorder or randomness of a system. The 2nd Law of Thermodynamics states that entropy always increases over time in a closed system, meaning that the disorder or randomness of the system will always tend to increase.

What causes a decrease in entropy and violation of the 2nd Law of Thermodynamics?

A decrease in entropy and violation of the 2nd Law of Thermodynamics can occur in a system when energy is added or when the system is not completely isolated. This can lead to a decrease in disorder or randomness, but it is only temporary as the overall trend of entropy increase will continue.

Can entropy be reversed and the 2nd Law of Thermodynamics be violated?

No, the 2nd Law of Thermodynamics is a fundamental law of physics and cannot be violated. While entropy can decrease in certain systems, overall it will always tend to increase. Additionally, any decrease in entropy is always accompanied by an increase in entropy elsewhere.

What are some real-life examples of a decrease in entropy?

One example of a decrease in entropy is the formation of a crystal from a liquid. In a liquid, molecules are in a more random and disordered state, but when they come together to form a crystal, they become more ordered and decrease in entropy. Another example is a living organism, which maintains a high level of order and low entropy through constant energy input and metabolism.

How does the 2nd Law of Thermodynamics apply to the universe as a whole?

The 2nd Law of Thermodynamics applies to the universe as a whole, as the overall trend of increasing entropy will eventually lead to the heat death of the universe. This is because, in a closed system, the available energy for work will eventually be used up, resulting in a state of maximum entropy where all energy is evenly distributed and no work can be done.

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