相對論與核裂變的問題

Althoug the number of nucleons and particles is the same, the masses of the nucleons do have a slight reduction. This reduction in mass of nucleons in nuclides of heavy elements, like urnaium, is more than that in lighter elements. Such mass reduction accounts for the binding energy, which is the energy holding all nucleons together in the nucleus. It is found that the binding energy per nucleon peaks at the element iron and decreases towards heavy elements.

The energy released in fision comes from the excess binding energy in heavy elements when they are splited to become lighter elements. This binding energy can be calculated using the mass-energy equation in special relativity.

E=MCC

你比較前後的質量，少了的質量就是轉為能量了。

氫原子是一粒proton加一粒electron構成。如果你真的量度一粒單獨的proton，再量度一粒單獨的electron，你會發現，總和是比一粒氫原子（atom）重一點點的。