Nuclear Fission explained
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- เผยแพร่เมื่อ 17 ก.ย. 2017
- Nuclear fission - the splitting of the atom...
How does this occur and why does it release a large amount of energy? The video covers all this, as well as a brief history of its discovery.
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Most wonderful physics channel
Thanks for working on Quanta to quarks at the mean time. I want you to also focus on Pauli Exclusion Principle and Manhattan Project. Thanks a lot!
+Rakesh Beniwal two good subjects though manhattan project could get out of hand. Lots of good docos out there on that topic. Exclusion principle is definitely in the list.
Hey there, I'm just struggling to understand how it all works. I understand there's the energy/mass equivalence and then what I'm getting from this is; the binding energy per nucleon of the two resulting atoms are higher so they weigh less in total (the mass is in the form of the binding energy?). But what I don't understand is how is the energy released when shouldn't it be being used to hold the resulting nucleons together (now that they need more binding energy). I know I'm missing something here because the questions are always in the Quanta to Quarks section and they say both fission and fusion release energy. In my head right now I'm thinking that there is no reason why the excess mass of the Uranium atom is exactly equal to the excess energy required to hold the atoms together and thus there is no change in energy from the system, the only thing i can think that would release binding energy is the release of the neutrons (if 3 are released from one, there is some of the binding energy that would have held the neutrons in place being released). Please help! Sorry if it's in this vid, I'm just not fully understanding.
OK
BE/n is determined by the mass defect, which is the difference between the mass of the atom and the mass of its parts.
If an atom as a greater BE/n, then its lost more mass.
so if fission occurs, we go from a lower BE/n to a higher BE/n
Yes mass is used to create the binding energy to bind the atoms BUT we still have overall LESS mass since we have increased BE/n
That mass difference (and this is NOT mass defect) is what produced the energy in fission.
I hope that helps
BTW, a video on fusion will be released this Monday
sorry, but why does Be/N increase after fission
@@PhysicsHigh you don't need binding energy to bind the nuclei together. The strong force does that by itself, you do not have to push against it. In fact, energy is released when nuclei bind together, THAT is where the energy in nuclear fission comes from. This released energy decreases the total energy of the nucleus and thus its mass according to E=mc^2
@@yasinkhan4620 The reason is in smaller atoms you have fewer nucleons where strong nuclear force (gluon) is acting; so, it is reasonably easier to work against the force since it is lower in amount. When it is extraordinarily humongous, coulombic force starts opposing strong nuclear force, while you work against it, which doubles the action. Thereof, it is incredibly simpler to have smaller or extremely gigantic nucleas detonated.
So, the energy released comes out in what form? Is it what propels the extra neutrons outward?
What about lise meitnet ?
Hi, this is really helpful but I have a question. When something fissions or alpha decays, what happens to the electrons? For example, if U-235 is hit by a neutron and fissions, are its electrons split between the two daughter nuclei? I'm trying to consider this from conservation of charge, so the electrons can't just vanish, but I don't understand where they go. Same with an alpha particle, it was detected due to its +2 charge so it cannot be a neutral helium atom, but that leaves 2 electrons unaccounted for. Thank you!!!!
P.S. How important would this question be for the HSC physics course?
You are right the electrons are sort of shared between the two nuclei, but yes there will be free electrons somewhere. You need to remember that in terms of scale, the electrons are very very far away form the nucleus and so play no part in the process.
Second thing though is you idea of conservation of charge. This means no electron is lost ie disappears. Some still flying off somewhere if it is released from the atom. This may be picked up by another charged particle, like the alpha particle.
Its akin to conservation of energy. A collision may result in less kinetic energy than before but thats because we 'lost' energy in terms of heat, sound etc. Its not truly lost, just in another form we cant 'recapture'. and the LCE is still true
This exchange of electrons happens all the time. Take charging your hair with a balloon. The balloon loses electrons and your hair gains the same amount of electrons (thats charge conservation). But both will eventually neutralise due to electrons give to air molecules (by your hair) or electrons picked up (by the balloon)
Does that make sense?
In terms of HSC, in radioactive decay you need to concern yourself with the nucleus