so they call this neptunium. first element beyondranium and that's neptunium 239. it's got a very, very short half-life. and you knowhat it does? it decays. and guess what it emits? begins with a b. no, not alpha. try it again. it emits a ba particle. okay. it emits a beta particle. and what does it turn into? how ma peoe can figure out what the number is here that couldn't dot before but maybe now can? show of hands. four people. wonderful. now, how many? what is it gonna be, gang? it's 94. 94, 94. what is the second planet that we named after discovering newn's laws? it wasn't neptune, it was what? - plo. - pluto. guess what we'd bealling this, gang? plutonium. plutonium. pu2. and you know what plutonium will do? plutium as welasnium35 ll undergo fission when a neutron taps it. d so this is used for power production. u235, used for power production. historical, when the bombs were dropped ck in world war ii, the bomb that devastated hiroshima was a uranium 235 bomb. you know how much uranium 235 was left after the bomb s detonated? almost none. the united states