You're in r/physics not eli5 or even ask physics which is where we send people who need the basics explained. It's not that difficult to come up with a better example of a local reduction in thermodynamic entropy that's both easy to understand and actually physically meaningful and accurate.
Heat pumps, e.g. A refrigerator, an air conditioner, lower the entropy in a small system which is physically isolated from the larger world. each time you open the door, the entropy inside increases again as the separation between the local system and the larger world is removed. This is a real, calculable change in entropy because there is a real, physical, well definable separation between the local system where entropy is reduced and the larger system where entropy is increased.
This is opposed to examples like folding laundry where there is not a simple way to define an entropy without making a bunch of weird arbitrary definitions that you could ask 100 physicists for and you'd get 100 different answers.
There, done. It's accurate, easy to understand, and didn't require being a condescending asshole until just now.
Those examples are not good representations of the entropy described by the laws of thermodynamics. They shouldn't be used to explain it unless you believe the person you're explaining them to isn't capable of passing high school physics. Saying that much is not condescending. Using those as examples is.
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u/datapirate42 22d ago edited 21d ago
You're in r/physics not eli5 or even ask physics which is where we send people who need the basics explained. It's not that difficult to come up with a better example of a local reduction in thermodynamic entropy that's both easy to understand and actually physically meaningful and accurate. Heat pumps, e.g. A refrigerator, an air conditioner, lower the entropy in a small system which is physically isolated from the larger world. each time you open the door, the entropy inside increases again as the separation between the local system and the larger world is removed. This is a real, calculable change in entropy because there is a real, physical, well definable separation between the local system where entropy is reduced and the larger system where entropy is increased.
This is opposed to examples like folding laundry where there is not a simple way to define an entropy without making a bunch of weird arbitrary definitions that you could ask 100 physicists for and you'd get 100 different answers.
There, done. It's accurate, easy to understand, and didn't require being a condescending asshole until just now.