5 ms·

Guess this is saying that the one kilogram of uranium is converted to fission products which are slightly lighter--one kilogram minus a butterfly--and the amoun

Guess this is saying that the one kilogram of uranium is converted to fission products which are slightly lighter--one kilogram minus a butterfly--and the amount of energy released from this difference is e=(mass of butterfly)*c^2

shadowgovt 5y ago
Yeah, the mass-energy relationship is at scales that are hard to wrap a human brain around. A charged laptop battery gains about 2 picograms of mass.
- mrtnmcc 5y ago
  Wait is that right? I thought charging a lithium battery was simply displacing electrons from cathode to anode, but the total number of electrons in the whole battery is conserved (and hence mass). Or is this converting that electric potential into an equivalent mass? Does this actually manifest as a difference on a scale?
  - shadowgovt 5y ago
    The total particle count is conserved. ... But the total mass of a molecule is also affected by the energy in the chemical configuration; the chemistry of the charged battery has more energy than the uncharged battery. https://physics.stackexchange.com/questions/195696/do-chemical-bonds-have-mass https://physics.stackexchange.com/questions/195696/do-chemic...
    - mrtnmcc 5y ago
      Interesting, so in the context of this broader discussion, if you displaced 1% of electrons in your body by a centimeter, you would weigh 10x more than you did originally. (Both gravitational mass and inertial mass increase)
      - wizzwizz4 5y ago
        And then you would die, instantly, and so would the surrounding countryside.
        ninju 5y ago
        And the countryside on the other side of the Earth as well
      - p1mrx 5y ago
        Assuming that you displaced all the electrons in the same direction, you'd produce a 1 cm electron cloud on one side of your body, and 1 cm of electron-deficient matter on the other side. If you could somehow maintain that configuration, you'd have a capacitor storing an enormous amount of energy, so it makes sense that the mass would increase.
    - da_chicken 5y ago
      Yeah, this is also why an empty hard drive should have less mass than a full one. It's an immeasurable amount, but it should be there. Adding energy to a system should increase it's mass. https://physics.stackexchange.com/questions/31326/is-a-hard-drive-heavier-when-it-is-full https://physics.stackexchange.com/questions/31326/is-a-hard-...
      - stickfigure 5y ago
        To be pedantic, I think you need to say "the act of writing to a hard drive adds mass". There is no reason to expect that writing a 1 or a 0 adds more or less mass; if there is a difference in energy states, it would depend on the encoding scheme.
      - deleted 5y ago
        [deleted]

shadowgovt 5y ago

Yeah, the mass-energy relationship is at scales that are hard to wrap a human brain around. A charged laptop battery gains about 2 picograms of mass.

mrtnmcc 5y ago
Wait is that right? I thought charging a lithium battery was simply displacing electrons from cathode to anode, but the total number of electrons in the whole battery is conserved (and hence mass). Or is this converting that electric potential into an equivalent mass? Does this actually manifest as a difference on a scale?
- shadowgovt 5y ago
  The total particle count is conserved. ... But the total mass of a molecule is also affected by the energy in the chemical configuration; the chemistry of the charged battery has more energy than the uncharged battery. https://physics.stackexchange.com/questions/195696/do-chemical-bonds-have-mass https://physics.stackexchange.com/questions/195696/do-chemic...
  - mrtnmcc 5y ago
    Interesting, so in the context of this broader discussion, if you displaced 1% of electrons in your body by a centimeter, you would weigh 10x more than you did originally. (Both gravitational mass and inertial mass increase)
    - wizzwizz4 5y ago
      And then you would die, instantly, and so would the surrounding countryside.
      - ninju 5y ago
        And the countryside on the other side of the Earth as well
    - p1mrx 5y ago
      Assuming that you displaced all the electrons in the same direction, you'd produce a 1 cm electron cloud on one side of your body, and 1 cm of electron-deficient matter on the other side. If you could somehow maintain that configuration, you'd have a capacitor storing an enormous amount of energy, so it makes sense that the mass would increase.
  - da_chicken 5y ago
    Yeah, this is also why an empty hard drive should have less mass than a full one. It's an immeasurable amount, but it should be there. Adding energy to a system should increase it's mass. https://physics.stackexchange.com/questions/31326/is-a-hard-drive-heavier-when-it-is-full https://physics.stackexchange.com/questions/31326/is-a-hard-...
    - stickfigure 5y ago
      To be pedantic, I think you need to say "the act of writing to a hard drive adds mass". There is no reason to expect that writing a 1 or a 0 adds more or less mass; if there is a difference in energy states, it would depend on the encoding scheme.
    - deleted 5y ago
      [deleted]