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reamio
March 19th, 2007, 06:05 AM
No, actually when you heat something you increase the level of order, therefore you decrease entropy. Things tend to go towards entropy, things tend to cool down.

Absolute Zero is absolute entropy.

I beg to differ. As far as I understand it,
There are 2 main types of entropy in a system: Positional disorder and Thermal disorder. In Positional disorder entropy increases as you change the state of matter from solid-liquid-gas and in reverse from gas-liquid-solid entropy decrease. in Thermal disorder entropy increases as heat increases and as heat decreases entropy also decreases. if there is an increases in disorder then the reaction will be spontaneous. if there is a decrease in disorder then it is spontaneous.

Think about it: the disorder in a solid cube of ice (crystals all perfectly aligned) is less than in water vapor (molecules shooting around the room rapidly in a random manner):rolleyes:

Also, I disagree with "... things tend to cool down". It depends on what temperature they started at. Things that are warmer than the ambient temperature tend to cool down, things that are colder tend to warm up.:D

In each case, the total entropy of the system increases according to the second law of thermodynamics.

Frunk: it's not my intention to nit-pick, I just wanted to get things straight for our colleagues who aren't familiar with the subject.

nbk2000
March 19th, 2007, 06:31 AM
Also, I disagree with "... things tend to cool down". It depends on what temperature they started at. Things that are warmer than the ambient temperature tend to cool down, things that are colder tend to warm up.

You can stop or reverse local entropy by expending energy, but the total entropy of the system will ALWAYS increase.

In the instance of the cold objects warming to ambient, that's because of the energy being expended by the sun is reversing entropy locally, but the total entropy of the Universe is ever increasing, and will continue to increase until all available energy, even that holding atoms together, is expended, and the Universe is nothing but an infinite expanse of sub-atomic particles at absolute zero.

IAMZERG
March 22nd, 2007, 11:23 PM
...and will continue to increase until all available energy, even that holding atoms together, is expended, and the Universe is nothing but an infinite expanse of sub-atomic particles at absolute zero.

That helps a whole lot... No-one, even "experts" on the subject have been able to adequately explain entropy for me. They say it's really complicated, but you made it really simple. Thanks!