Hi guys,
<<uranium releases energy when split because the produced nuclei are more stable (have less potential energy). same is true for the fusion of hydrogen for instance. the resulting nuclei have less potential energy...hence energy is released by their creation.>>
I thought the actual mechanism of energy release during fission was described earlier. The radioactive stability of an atom is not related to the energy released during fission. They are actually 2 different forces. Stability has to do with Radioactive decay. This is an energy release mechanism, but it results from the "weak nuclear force" which is in a completely different catagory from the energy released during fission. During fission the mass/energy difference from the original fissile material (U235 P239 etc.) and the resulting fission product is the source of the energy release. Basically it take more "binding energy" to hold a big nucleus together. The nuetrons and protons donate some of their mass in order to hold it all together. With large atoms they must donate proportionally more of their mass. For example, if you split them in half the resulting two atoms formed will require proportionally less mass/energy to be donated from the protons and nuetrons in the nuclei. So you have a surplus of energy that gets released in various ways - heat, kinetic, photons etc. Basically it take less combined energy to hold the two smaller atoms together than it takes to keep one big atom together. Thats why splitting certain atoms yield tremendous energy.
If you look at E=MC2 you can see that the Mass (M) part of the equation is only = to the Energy (E) part of the equation if you multipy it by C (the speed of light) squared! So the fact that the protons and nuetrons donate mass in an atom is really significant. Mass is really a super condensed form of energy.