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Fusion 9,122 views

Teacher/Instructor Kendal Orenstein
Kendal Orenstein

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.

Fusion involves the combining of atomic nuclei. 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.

Alright so let's talk about nuclear fusion. Nuclear fusion is the combining of atomic nuclei, we're going to fuse 2 nuclei together. Well why would we go about doing that? Let's look at this graph here, this graph on the x axis where we're going to have mass number and the y axis where we're talking about binding energy. And binding energy is energy needed to break one mol of nuclei into its nucleons. So it's how much energy it takes to break apart a nucleus. So here at this band in the middle that I had written is at mass number about 60 and notice it has the highest binding energy. So it's going to take a lot of energy to break apart that nucleus. Things that have a higher mass number than 60 are going to under go through what we call fission. Fission is when we break apart the nuclei and get towards the mass number closer to 60. Over here in the low mass number we're going to get through fission, we're going to push those nuclei together to get it to it's very stable nucleus of 60. So let's talk about nuclear fusion a bit more, alright so here we have 4 low atomic number the smallest atom, hydrogen and we're going to fuse those guys together and we're going release some beta particles or electrons and 2 helium nuclei and notice a lot of energy is going to be released.

This guy look a little more stable as you can see than this guy okay, so how does this go by happening we have to actually bombard these hydrogen particles together very very high speeds in order for them to fuse together because don't forget when these guys are close to each other, when these nucleus get close to each other they're 2 positive things they're going to repel. So if they have tons of energy to over come that repulsion to get them close enough together, where they're going to bind and fuse and when they actually do tons of energy is going to be released and that energy can be used to, it can be harnessed to energize anything to do anything we want to. So why don't we use this if a lot of energy is being produced, why don't we use this instead of nuclear fission? Because nuclear fission is what's actually used in nuclear power plants and actually give off by-products that are pretty harmful. So here are some pro's let's go over the pros of talking about nuclear fusion.

Well the things that we need to do in nuclear fusion is, we have high abundance of them so we have these small particles from the planet, hydrogen, helium things like that, that are very small that we have a lot of on this earth we have a lot of these smaller particles. We don't have as many bigger particles that are used for nuclear fusion and so, that's a really good thing that we have a lot of them. We also get no radio-active by-products meaning nothing from this reaction is harmful to the environment. Helium atoms are not harmful to the environment, beta particles are totally fine. So we have no radio-active by-products as we do when we talk about nuclear fusion.

We also get significantly more energy when this reaction occurs, a lot more energy thousands of times more energy with fusion than we do with fission. So again why do ever use this? Well here's why it's really, like I said before, it takes a lot of energy to overcome that repulsion force that these 2 nuclei have together so it's going to take a lot of energy to sustain and initiate this particular reaction. Think about it, if this reaction fusion actually happens in the sun, the sun is extremely hot, takes a lot of energy for that reaction to happen. It's only achieved at high temperatures 40 million Kelvin, that's insanely high it's actually impossible to find a container that can harness that sort of not harness but it can contain that sort of high temperature. This is actually attained in atomic explosions we need atomic explosions to actually initiate this temperature or this yeah the temperature and the actual energy needed to actually have the reaction move forward. So can you think of as a container that can contain that? So neither can we, so this reaction is not used to initiate energy which is why you might think about things are being tossed around in the Chemistry communities such as like cold fusion or other ways we can use, we can actually have this type of reaction to get this type of energy to have like hydrogen fuel cells things like that. So for now we're going to stick with nuclear fusion but hopefully in the future nuclear fission will be the way to go.