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| | In this context "increasing disorder" means the decline in organization that occurs without intelligent intervention. Imagine your old room at your parent's house. Remember how easy it was to let the room turn into a uniform mess (disorder) and remember how hard it was to clean it up until it fit a specific, non-uniform design (order). Not cleaning up would always result in an increase of entropy in your room! | | In this context "increasing disorder" means the decline in organization that occurs without intelligent intervention. Imagine your old room at your parent's house. Remember how easy it was to let the room turn into a uniform mess (disorder) and remember how hard it was to clean it up until it fit a specific, non-uniform design (order). Not cleaning up would always result in an increase of entropy in your room! |
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| − | Now, in nature there is no one to clean up the universe, only chances. The chance of something becoming orderly is essentially zero, which it is a certainty that things will become more disorderly.
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| − | On a universal scale a tidy room would be a universe which has pockets of above average concentrations of energy (if you - incorrectly - assume relativity [[E=mc²]] this includes matter as well.)
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| − | A messy room would be a universe in which all energy is equally spread out.
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| | The flow of energy (by heat exchange) to places with lower concentrations is called the "heat flow." | | The flow of energy (by heat exchange) to places with lower concentrations is called the "heat flow." |
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| − | The often heard argument that this law disproves an eternal universe is true, since in that case maximum entropy would have been reached already. A counter-argument to this would be to suggest that the universe is still in the process of approaching maximum entropy. | + | The often-heard argument that this law disproves an eternal universe is true, because in that case maximum entropy would have been reached already. A counterargument to this would be to suggest that the universe is still in the process of approaching maximum entropy. |
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| − | There are many different ways if stating the second law of thermodynamics. An alternative statement of the law is that heat will tend not to flow from a cold body to a warmer one without intelligent invervention, or work, being done, as in the case of a [[refrigerator]]. Other statements include that it is impossible for an [[engine]] to convert [[heat]] perfectly (I.e. at 100% efficiency) into [[work]]. These statements are qualitative and stating the second law in terms of [[entropy]] makes the law quantitative. | + | There are many different ways if stating the second law of thermodynamics. An alternative statement of the law is that heat will tend not to flow from a cold body to a warmer one without intelligent intervention, or work, being done, as in the case of a [[refrigerator]]. Other statements include that it is impossible for an [[engine]] to convert [[heat]] perfectly (I.e. at 100% efficiency) into [[work]]. These statements are qualitative and stating the second law in terms of [[entropy]] makes the law quantitative. |
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| | This law makes it impossible to build a [[perpetual motion machine]] - the increase in entropy inevitably derails the system even if its [[energy]] remains constant (as described by the [[Conservation of Energy|first law of thermodynamics]]). | | This law makes it impossible to build a [[perpetual motion machine]] - the increase in entropy inevitably derails the system even if its [[energy]] remains constant (as described by the [[Conservation of Energy|first law of thermodynamics]]). |
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| | where <math> \frac{dS_{universe}}{dt}</math> is the rate of change of [[entropy]] of the [[universe]] with respect to time. | | where <math> \frac{dS_{universe}}{dt}</math> is the rate of change of [[entropy]] of the [[universe]] with respect to time. |
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| | + | Another way of viewing the second law is in terms of probability. In nature there is no one to clean up the universe, only chances. The chance of something becoming orderly is essentially zero, which it is a certainty that things will become more disorderly. |
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| | + | On a universal scale a tidy room would be a universe which has pockets of above average concentrations of energy (if you - incorrectly - assume relativity [[E=mc²]] this includes matter as well.) |
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| | ==Second Law compared with other physical laws== | | ==Second Law compared with other physical laws== |