Under what circumstances is the law of conservation of mass true? Law of conservation of mass-energy?

Chastity Doderer: "A soul/spirit/consciousness is just a bunch of energy right?" A human "soul" is just the subjective experience of the processes of a human nervous system. Just like the internet would not exist without the wires, hard drives, modems, and terminals that give rise to it, consciousness would not exist without a functional nervous system. Take away the hardware infrastructure, or even damage it significantly, and it's just lights out. "Therefore it's something physical, and can not be created or destroyed." Matter/energy cannot be destroyed, but it can be transformed. A stick of dynamite is just a bundle of matter/energy, but you have no problem envisioning the transformation of that energy into sound, heat, and light energy when it explodes. Afterward, although the atoms that made up the stick of dynamite still exists, the stick itself no longer does. Similarly, when you cremate a body, the energy stored in its molecules is dissipated into the atmosphere a! s heat and light. When you bury a body, the energy stored in its molecules is used to nourish the decomposition agents that pick it bare. Just because the matter and energy of some object continue does not mean the thing itself continues as well....Show more

Sena Highman: Conservation of mass is true when the reaction doesn't involve matter-energy conversion. Stuff like chemical reactions, phase changes, and most scenarios in general would conform to conservation of mass.That is, none of the mass is converted into energy per Einstein's E=mc^2 formula, or vice versa.So, with nuclear fission, nuclear fusion, matter-antimatter reactions, conservation of mass is out, and you have to use conservation of mass-energy.In nuclear fission or fusion, mass is converted to energy in the reaction, so at the end, you get some energy out and there's a net decrease in mass.With matter-antimatter, two equal but opposite particles of matter and antimatter come together and release en! ergy in the form of a photon. Both particles cease to exist ! in the process, so there's a decrease in mass.However, it's also theoretically possible to get one particle of matter and one particle of anti-matter coming out if two photons come together just right. Two new particles are generated, so you get a gain in mass....Show more