beta particle, beta particle, betawhat's a beta particle? - electron. - electron. now we have to make the symbol for electron. r electron, get it? mm-hmm. at'shetomic mber of an eltron? - negative o. - atomicbe negane wh is atomic numr, anyy? charge, right? - netive one. - negave one what's theass of an electron? zero. well, it's closer to zero than it is to one if one is the mass of a proton neutron. and this has got, like, abou2,0th the mass. that'sloser to zero than to one. so we round of atomic mass number, anyway. this is ze. now, what does the thorium become? well, what do we got over here for an atomic nuer 91 do you see it's 91? yeah. 91. and what's the mass gonna be? - 89. - now, what has 91? protactinium. - is it gonna be 91, gang? - yeah. let's check. - 91 minus 1 equals 90. - correct. it's 91. that's interesting. some people think that radioactive decay, you start with uranium and work down, down, dow down the periodic table approaching hydrogen. not true. when beta particles are emitted, you climb up the table, gang. you see that? what happens in that

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 shot its arsenal, one bomb, none left to speak of. you know what the bomb that hit nagasaki was? plutonium. plutonium. does the same thing. plutonium is made from uranium 235--238, very plentiful, but you got to bombard it with ne