How is the entropy of the universe increasing when entropy is simply transferred?


by ninjarawr
Tags: entropy, increasing, simply, transferred, universe
ninjarawr
ninjarawr is offline
#1
Jul4-10, 03:35 AM
P: 12
For example, an increase in the entropy of the system will be exactly equal to the entropy decrease of the surroundings. So the net change in the entropy of the system and its surroundings is zero.

Putting this in perspective to all the systems and environments in our universe, how is the universe always increasing in entropy?


Thanks in advance!

ninjarawr
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Tusike
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#2
Jul4-10, 05:31 AM
P: 126
I'm not really sure the if the entropy of a system increases, the entropy of the surroundings will decrease. There's no conservation of entropy-law. If you have a closed system, it's entropy has nothing to do with the surroundings.
hikaru1221
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#3
Jul4-10, 07:55 AM
P: 802
Quote Quote by ninjarawr View Post
For example, an increase in the entropy of the system will be exactly equal to the entropy decrease of the surroundings.
Oh, really? Prove it

Gear.0
Gear.0 is offline
#4
Jul4-10, 08:17 AM
P: 66

How is the entropy of the universe increasing when entropy is simply transferred?


I think what may have confused you is that if you look at a 'non-closed' system you can observe an entropy decrease, but this means that entropy somewhere else was increased.
So entropy is still increasing overall.

Perhaps you read something like that and generalized it to a conservation law..
However, it doesn't work the other way around. So an entropy increase does not have to accompany an entropy decrease.
ninjarawr
ninjarawr is offline
#5
Jul4-10, 07:49 PM
P: 12
Quote Quote by Gear.0 View Post
I think what may have confused you is that if you look at a 'non-closed' system you can observe an entropy decrease, but this means that entropy somewhere else was increased.
So entropy is still increasing overall.

Perhaps you read something like that and generalized it to a conservation law..
However, it doesn't work the other way around. So an entropy increase does not have to accompany an entropy decrease.
The statement "an increase in the entropy of the system will be exactly equal to the entropy decrease of the surroundings. So the net change in the entropy of the system and its surroundings is zero" is straight of a kaplan physics review book for the MCAT. It didn't make sense to me because it does imply a conservation law, and then it confused me even more on the concept of entropy....if the equation for change in entropy is delta S = Q/T, if the environment loses heat to the system, wouldn't the environment have a negative delta S (and the system positive)? Does that mean entropy is decreased in the environment, and increased by the same amount by the system?
ehild
ehild is offline
#6
Jul4-10, 11:54 PM
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Thanks
P: 9,818
Fom Wikipwdia: "In systems held at constant temperature, the change in entropy, ΔS, is given by the equation

[tex] \Delta S = \frac{Q}{T} [/tex],

where Q is the amount of heat absorbed by the system in an isothermal and reversible process in which the system goes from one state to another, and T is the absolute temperature at which the process is occurring."

ehild


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