Warning! Nerd Post!
This is another long nerdy post about nuclear stuff - the one I've been warning about. I broke it down into a few different parts to try and keep it sensible.
Part 1. Nuclear fission: How and where the energy is released, in its various forms.
Here is what happens at the subatomic level when the nucleus of an atom splits, or undergoes nuclear fission. This event releases a phenomenal amount of energy, and where this energy ends up being deposited (or lost) is interesting.
