Rutger's University
M.Ed., Columbia Teachers College
Kendal founded an academic coaching company in Washington D.C. and teaches in local area schools. In her spare time she loves to explore new places.
Fissioninvolves splitting atomic nuclei into fragments. Atoms with mass numbers close to 60 have been found to be the most stable. Atoms with mass numbers lower than 60 undergo fusion while atoms with higher mass numbers undergo fission. The energy needed to break one mole of nuclei into individual nucleons is called binding energy.
We're going to talk about nuclear fission, nuclear fission is actually what happens in nuclear power plants when we're actually gaining energy I'm talking about nuclear reaction that's when we split the split the nucleus into fragments and why do we do that? So let's look at this graph.
这张图在y轴上能源和有约束力x axis has mass number and just a heads up binding energy is the energy needed to break up one mole of nuclei into it's into it's individual nucleons or individual particles neu- protons and neutrons. So for low mass numbers down here, they're actually it takes, doesn't take a lot of energy for us to break apart into the apar- into the, into other separate parts. Up here also doesn't you get to a higher mass numbers it doesn't take it's much energy also to break itself up into several parts so the most stable as we found through many experiments is the mass numbers close to 60. 60 mass number actually has the most stable nucleus take a lot of energy for us to mess with it and break it apart and do things with it, so all atoms are trying to get to the point where they have a mass number of 60 so things over here are going to breakdown things with higher mass numbers are going to breakdown things with lower mass numbers are going to start fussing together that's fusion and we'll talk about that another time.
Okay so uranium is actually what's typically used when [IB] when dealing with nuclear fission and power plants so what we do is we bombard uranium with high speed neutrons what that does it gets to very very unstable nucleus and so it's able to breakdown much quicker, this has a half life of you know couple of million years this actually has a half life much faster so then what this does is spontaneously breaks down into these products krypton, barium and then more neutrons okay. These guys are extremely unstable, this we're talking about nuclear waste it's because these guys are produced; krypton and barium. These guys are nuclear waste that we actually they are very unstable they'll continue to decay giving up lots of energy giving up lots of bad things in the environment so this is when you're talking about having to be nervous about nuclear energy it's because these by products are present.
Now this because of the [IB] reaction this is very very unstable so it has a lot of energy within the nucleus so when it breaks down it's going to explode not not explode necessarily but give up a lot of energy and it's going to heat up water things like that give up a lot of energy and we're able to harness that energy to use things for you know power if you're all resources so what, then guys is gives off 3 another product of this reaction is 3 neutrons and so what happens with these 3 neutrons is they and then can start the reaction over again and bond the uranium atom and then it goes on and so forth. If we have enough of uranium atoms we call that critical mass that means that the reaction can continue and continue and continue without us having to do anything to it so this is actually basically the basic component of how nuclear reactions or nuclear power plants work essentially it's breaking down uranium atoms into and giving up a lot of energy and being hunt this energy for use in other places, so this is essentially what nuclear fission is.
