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Adiabatic lapse rate

  1. Dec 29, 2014 #1
    I Think I understand this, but when I look it up, I keep reading about work done and energy used, which puzzles me.
    The simple way I have always thought about it is, when you expand a gas you also expand the heat it contains, so while it contains the same amount of heat, it's concentration (which I equate to temperature is reduced) it you were then to compress it back to it's original volume, it would have it's origional temperature, (no energy used or lost)
    Is this wrong.
    Thank you
  2. jcsd
  3. Dec 29, 2014 #2


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    This is called the First Law of Thermodynamics. It's how the "bookkeeping" on all forms of energy is done.
    Any process taking a system from one state to another and returning it to the original state always involves work done on and/or by the system, and/or heat lost and/or gained by the system.
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