When an induced Nuclear Fission reaction occurs, mass is 'lost', and by 'lost' I of course mean converted into energy, via Einstein's equation E=mc^2 (Proving matter and energy are relative). However, it just makes one wonder, why is that mass lost? Why are the products (daughter isotopes) lower in mass than the reactant (parent isotope)? It suggests that mass was converted into energy, but for what purpose? Apparently, different isotopes have different levels of binding energy (The more binding energy per nucleus, the more stable the isotope), and the most stable isotope is iron-56, so, as expected, the products of a nuclear fission reaction are closer in mass to 56, than the reactant was (To become more stable). Now, since the closer an isotope is in mass to Iron-56, the more binding energy it has, it would make sense that the products would have less mass, losing it due to it being converted to the extra binding energy needed to hold the new nucleons together. Now that, fellows, is where my problem comes in. When we want to find out the energy yield of a Fission reaction, we take the Mass Defect (Difference in mass) from the Reactant to the Product, and input that mass difference into the equation E=mc^2, to give us the amount of energy that would be created from that amount of mass. However, if I am not mistaken, would the energy value we get, merely be the amount of binding energy produced by transforming the mass into energy? Why do we act like that value is the value we yield or receive? We don't harness that binding energy and use it to transform into thermal energy, to eventually generate electrical energy, do we? That's my question. When we calculate the energy value from a given mass defect after a nuclear reaction, is all that energy just binding energy, that was created from the mass, or is some of it different types of energy, such as thermal, used to generate electricity (by boiling water and turning a turbine which is connected to a magnet and a metal coil, for those of you that are wondering how the thermal energy produces electrical energy)? I know it's a lot, but two more questions arise from the last one, depending on the answer; If all the energy is simply just binding energy, then how do we harness it to create thermal energy for electricity production (If we took some of that energy for transformation, would the nucleus of the isotope not begin to dis-incorporate, not having enough binding energy to keep itself together)? However, if the energy is, in fact, multiple forms of energy (binding, thermal, electromagnetic, etc), when why did the atom lose mass to create the unnecessary forms (it should only need the binding energy), and why do we use the same mass defect value (which gives us the total energy produced) and say that we yield or harness all of that energy into the thermal energy we need, when realistically, we are only actually using a fraction of that energy value that we calculated?