Hi, in my environmental chem class at school, we vaguely touched on the subject of nuclear power and such. my question has to do with the splitting of the U235 or 238 atoms in reactors, as well as those in, say, nuclear weapons. my teacher (and diagrams) said that the splitting occurs when the uranium atoms are hit with neutrons, splitting them apart. but where does this initial neutron come from to split the first one, or does it happen some other way? thanks.