Laws of thermodynamics: Difference between revisions
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#[[Energy]] is neither created nor destroyed. It's all in a closed system, that system being the [[universe]] itself. Let's say you're about to drop a [[ball]]. The ball has energy—[[potential energy]]—and when it falls, that potential energy is converted to [[kinetic energy]]. From a mathematical perspective, the change in internal energy, <math>\Delta U</math>, equates to the [[heat]] added minus the [[work]] done by the system. | #[[Energy]] is neither created nor destroyed. It's all in a closed system, that system being the [[universe]] itself. Let's say you're about to drop a [[ball]]. The ball has energy—[[potential energy]]—and when it falls, that potential energy is converted to [[kinetic energy]]. From a mathematical perspective, the change in internal energy, <math>\Delta U</math>, equates to the [[heat]] added minus the [[work]] done by the system. | ||
#Heat, of course, flows from a hot body to a cold body. Think of a [[Silver Spoon|silver spoon]]. It's at room temperature. You put it in a pot of boiling [[soup]] and stir it, and suddenly it's hot. The metal is conductive, and so heat easily transferred from this hot body to this cold body. I don't know what to say about a [[wooden spoon]], though. Entropy, <math>\Delta s</math>, is greater than 0. Apparently the use of a [[time machine]] violates this law, despite time machines not necessarily relying on heat. | #Heat, of course, flows from a hot body to a cold body. Think of a [[Silver Spoon|silver spoon]]. It's at room temperature. You put it in a pot of boiling [[soup]] and stir it, and suddenly it's hot. The metal is conductive, and so heat easily transferred from this hot body to this cold body. I don't know what to say about a [[wooden spoon]], though. Entropy, <math>\Delta s</math>, is greater than 0. Apparently the use of a [[time machine]] violates this law, despite time machines not necessarily relying on heat. | ||
# | #At 0 K, where there is no motion at all, the value of entropy is 0. This is where we get [[Heat Death of the Universe]]. | ||
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Latest revision as of 03:50, 21 October 2024
There are three laws of thermodynamics.
- Energy is neither created nor destroyed. It's all in a closed system, that system being the universe itself. Let's say you're about to drop a ball. The ball has energy—potential energy—and when it falls, that potential energy is converted to kinetic energy. From a mathematical perspective, the change in internal energy, , equates to the heat added minus the work done by the system.
- Heat, of course, flows from a hot body to a cold body. Think of a silver spoon. It's at room temperature. You put it in a pot of boiling soup and stir it, and suddenly it's hot. The metal is conductive, and so heat easily transferred from this hot body to this cold body. I don't know what to say about a wooden spoon, though. Entropy, , is greater than 0. Apparently the use of a time machine violates this law, despite time machines not necessarily relying on heat.
- At 0 K, where there is no motion at all, the value of entropy is 0. This is where we get Heat Death of the Universe.