20 ms·

You keep using this word "used", I do not think it means what you think it means... Energy is one of those strange things, where consumption is not necessarily

You keep using this word "used", I do not think it means what you think it means... Energy is one of those strange things, where consumption is not necessarily destruction. You 'used' a joule of energy when you heated up your coffee this morning, then dumped the waste heat to the rest of your kitchen, where it became an input for another part of the cycle. The energy did not go away when you consumed it, and in this case most of the energy 'used' in the production of a cup of coffee was never lost. [I kid, I kid, I know you meant negentropy, but I just couldn't help myself.]

cpach 11y ago
Good point! The trouble is just that many popular sources of energy has lot of negative effects ;-)
PepeGomez 11y ago
Energy is about the only resource where this doesn't hold true.
- vixen99 11y ago
  In theory at least, all non-radioactive elemental resources are recoverable from whatever combinations in which they are found, given sufficient energy and information.
  - PepeGomez 11y ago
    Exactly.
- jdmichal 11y ago
  Energy is the only resource I know about where there is a physical law stating that this must be true. (To be fair, you could have less energy offset by more mass. But the point stands.)
  - PepeGomez 11y ago
    Not if the thermodynamic laws hold true.
    - jdmichal 11y ago
      ... That's exactly what I was referring to? You seem to be confused. Your responded to a post stating that energy is never destroyed, with the sentence: "Energy is about the only resource where this doesn't hold true."
      - PepeGomez 11y ago
        Once you use the energy and it turns into heat, you can no longer use it.
        jdmichal 11y ago
        First, heat is energy. Second, you can use heat as heat. Third, you can use heat to boil water to turn a turbine to create electricity, which you can use to do very many things, including create heat.
        PepeGomez 11y ago
        No, you can't do that. If you could do that, you could build a perpetuum mobile.
        jdmichal 11y ago
        Yes, you can: https://en.wikipedia.org/wiki/Waste_heat_recovery_unit https://en.wikipedia.org/wiki/Waste_heat_recovery_unit Now, whether we can effectively use the energy is an entirely other question. There's plenty of technical limitations. But in a closed system there's no reason an object cannot have perpetual motion with perfect energy recovery. Of course, closed systems don't help us, because they cannot exert useful work outside of the system.

cpach 11y ago

Good point! The trouble is just that many popular sources of energy has lot of negative effects ;-)

PepeGomez 11y ago

Energy is about the only resource where this doesn't hold true.

vixen99 11y ago
In theory at least, all non-radioactive elemental resources are recoverable from whatever combinations in which they are found, given sufficient energy and information.
- PepeGomez 11y ago
  Exactly.
jdmichal 11y ago
Energy is the only resource I know about where there is a physical law stating that this must be true. (To be fair, you could have less energy offset by more mass. But the point stands.)
- PepeGomez 11y ago
  Not if the thermodynamic laws hold true.
  - jdmichal 11y ago
    ... That's exactly what I was referring to? You seem to be confused. Your responded to a post stating that energy is never destroyed, with the sentence: "Energy is about the only resource where this doesn't hold true."
    - PepeGomez 11y ago
      Once you use the energy and it turns into heat, you can no longer use it.
      - jdmichal 11y ago
        First, heat is energy. Second, you can use heat as heat. Third, you can use heat to boil water to turn a turbine to create electricity, which you can use to do very many things, including create heat.
        PepeGomez 11y ago
        No, you can't do that. If you could do that, you could build a perpetuum mobile.
        jdmichal 11y ago
        Yes, you can: https://en.wikipedia.org/wiki/Waste_heat_recovery_unit https://en.wikipedia.org/wiki/Waste_heat_recovery_unit Now, whether we can effectively use the energy is an entirely other question. There's plenty of technical limitations. But in a closed system there's no reason an object cannot have perpetual motion with perfect energy recovery. Of course, closed systems don't help us, because they cannot exert useful work outside of the system.