Molecular speed and temperature

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Discussion Overview

The discussion revolves around a hypothetical air filter that selectively allows air molecules to exit and enter a house based on their speed, and its potential effects on the temperature inside the house. The conversation touches on concepts related to thermodynamics and thought experiments.

Discussion Character

  • Exploratory, Conceptual clarification, Debate/contested

Main Points Raised

  • One participant proposes a scenario involving a filter that allows only fast-moving air molecules to exit and slow-moving molecules to enter, questioning the implications for indoor temperature.
  • Another participant references "Maxwell's demon" as a related concept, suggesting that the proposed filter could violate the second law of thermodynamics.
  • A further contribution asserts that constructing such a filter is not feasible, reinforcing the thermodynamic implications discussed.

Areas of Agreement / Disagreement

Participants express differing views on the feasibility of the proposed filter and its implications for thermodynamics, indicating that the discussion remains unresolved.

Contextual Notes

The discussion does not clarify the assumptions behind the proposed filter or the specific conditions under which it operates, leaving some aspects open to interpretation.

Himanshu_6174
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Imagine a special air filter placed in a window of a house. The tiny holes in the filter allow only air molecules moving faster than a certain speed to exit the house, and allow only air molecules moving slower than that speed to enter the house from outside. What effect would this filter have on the temperature inside the house?
 
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Google for "Maxwell's demon".
 
Essentially, this filter violates the second law of thermodynamics by cooling the house and heating up the outside, even if it is already warmer outside than inside the house. This is very similar to a thought experiment known as "Maxwells Demon", as mentioned by Nugatory.

Essentially, there is no way to construct such a filter.
 
Thanks :-) both of you
 

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