Question by : Why does nuclear fission AND fusion release energy?
The Sun undergoes nuclear fusion, combining hydrogen to form helium and so on, but it also releases light energy in the process. Nuclear fission (splitting the atom), however, also releases light and heat energy. How does this work? I would think that nuclear fusion would take IN energy in order to fuse together the nucleuses of atoms. And then when an atom splits, energy would be released because energy is stored to keep the bond between nuclear particles. So why would both processes release energy?
Best answer:
Answer by Roger S
In both cases the mass of the objects after the reaction is less than before the reaction. The lost mass has been converted into energy in the form of electromagnetic waves.
What do you think? Answer below!
2 Responses
With atoms that are lighter than iron, fusion releases energy (and fission absorbs it).
With atoms that are heavier than iron, fission releases energy (and fusion absorbs it).
Iron atoms are at the bottom of the energy slope; it takes energy to fuse or split iron atoms.
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Nuclear fission ( splitting ) : You split one atom into two other atoms with lower masses. Intuitially you would say the sum of the mass of those two atoms would result in the mass of the original atom you have split. But this isn’t the case. Some mass is lost. This mass has been converted into energy ( relatively very very large energy ). You can calculate this energy by the formula E=mc².
Nuclear fusion. This is just the opposite. You fuse 2 atoms together into 1, but the mass of this one is less than the sum of your original 2 masses. In this case also some mass has been lost, which releases energy.