3 ms·
From chemical reactions (breaking chemical bonds), as opposed to nuclear reactions. There's a certain amount of energy required to shove a bunch of stable molec
by JabavuAdams 9y ago
From chemical reactions (breaking chemical bonds), as opposed to nuclear reactions. There's a certain amount of energy required to shove a bunch of stable molecules together into a (more) unstable molecule (fuel, explosive). When that unstable molecule (fuel) is burned, it breaks apart into more stable products and releases the energy that was required to combine them in the first place.
- davrosthedalek 9y agoIndeed, but you will find that the fuel is by the same amount heavier than the stable molecules you used to make it.
- JabavuAdams 9y agoI'm having a hard time believing that. If I heat 100 molecules of water ice to melting, the 100 molecules of liquid water aren't more massive. The energy went largely into kinetic energy, not changing the atomic number of the atoms. Ok, that's a phase change, not a chemical reaction. I've changed the momentum, not the mass. Are you saying this would be encompassed in the full form E^2=m^2 c^4 + p^2 c^2 ?
- davrosthedalek 9y agoIndeed, in the m term, not in the p, which would be the total momentum of the water system in your frame. For more mind-boggling numbers see for example [1] [1] https://www.huffingtonpost.com/quora/is-a-hot-object-heavier-t_b_2717229.html https://www.huffingtonpost.com/quora/is-a-hot-object-heavier...
- JabavuAdams 9y agoHoly sh*t! Is this effect typically taught / introduced in a GR course? Why did I not know this!? EDIT> Is there any way to derive this outside of GR? EDIT2> I notice that you were careful to say "heavier", not more "massive". Does this point to the effect being part of the gravitational interaction specifically?
- davrosthedalek 9y agoAFAIK, Gravitational mass == inertial mass, so I could have said massive instead.