ALL Nuclear Physics Explained SIMPLY

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CHAPTERS:
0:00 Become dangerously interesting
1:29 Atomic components & Forces
3:55 What is an isotopes
4:10 What is Nuclear Decay
5:45 What is Radioactivity - Alpha Decay
6:31 Natural radioactivity - Beta & Gamma decay
9:03 What is half-life?
9:41 Nuclear fission
10:48 Nuclear fusion

SUMMARY
In this video, I summarize All Nuclear Physics in about 10 minutes. Atoms are made of a positively charged nucleus surrounded by negatively charged electrons. The nuclei of atoms are made up of protons and neutrons. These are called nucleons. Because all protons have the same charge, they repel. And force can be calculated using coulombs law. Two protons separated by the width of a neutron repel with a force of 60 Newtons, or 12 lbs!

But what keeps them from flying apart is an even stronger force the strong nuclear force. It's about 100X stronger than electromagnetism. But this force only operates at very small distances, about the width of a proton. And it only operates within and between nucleons. Electrons, photons, and neutrinos are not affected by it. It's like Velcro. Nucleon stick together when really close, but have no affect when far apart.

The number of protons in an element is solely responsible for its chemical and physical properties. A given element or atom can have the same number of protons, but different numbers of neutrons. These are called isotopes of the element. They have exactly the same chemical properties and differ only in mass.

Stable nuclei consist of roughly the same number of protons and neutrons. The neutrons serve to provide additional strong force needed to keep the nucleus stable. Without neutrons, not even two protons can be held together against their repulsion.

Free protons are stable, but free neutrons are not stable. Lone neutrons decay into a proton, an electron, and an antineutrino within 15 minutes. But inside a nucleus they remain stable because it is energetically unfavorable for them to decay.

If a nucleus is very large, or has an excess number of protons or neutrons, this causes alpha decay, which is a helium nucleus consisting of 2 protons and two neutrons. This is what we call radioactivity.

There are three forms of natural radioactivity, alpha, beta and gamma-decay. A beta-particle is a high-energy electron. This occurs in very large nuclei when a neutron decays even though it is in the presence of protons. This gives off an electron and an antineutrino. This electron is the beta-particle.

A gamma-particle is a high-energy photon. Gamma-rays are usually emitted by excited nuclei that have been created after either an alpha or beta decay. These nuclear processes release high energy photons is because they involve the strong force with is very energetic.

Alpha-particles can be stopped by a thin piece of paper. Beta-particles can penetrate your skin, but can be stopped by a sheet of aluminum foil. But gamma-rays can penetrate through an inch of lead.

A radioactive nucleus is characterized by its “half-life.” What this means is that if I have a 16 atoms, with a half-life of 1 week, then one week later I will have ½ or 8 atoms remaining. In 2 weeks, I will have 4 and so on. The half-life is a statistical concept, and we can't predict in advance which specific atoms will decay.

If a large nucleus, like some isotopes of uranium is hit by a particle, usually a neutron, then it will split into two smaller nuclei. This is called nuclear fission. If the total mass of the two smaller nuclei is less than that of the uranium before it was hit, the missing mass is turned into energy via E = mc2. This is called fission.

If there is enough fissionable nuclei in high enough concentration, then it is possible for the thrown off neutrons to, in turn, fission more nuclei, creating a chain reaction. This is the mechanism behind an atomic bomb.
#nuclearphysics
Fusion happens when two small nuclei such as hydrogen, which consists of only a single proton, can be brought close enough together that they fuse into a single nucleus. Fusion is very difficult to achieve, because the protons strongly repel each other. Only gases heated to millions of degrees Celsius have atoms moving fast enough to fuse. In the sun this process is easier because of the assistance of gravitational pressure in the core. Quantum tunneling also plays a role.

[bhgtree]

Arvin is a brilliant teacher, we need more like him to teach and explain mathematics, science and engineering, with the hope the many young (and not so young) decide to study these subjects.
Thank you, Sir.

[douglasboyle]

I've known all of these things since I was in high school essentially (thirty years ago) but I still watch channels like yours because I can still always learn something or get some nuance. And this time was no different, I never completely grasped why the Strong force is eventually overcome in large nuclei by the EM force, I never caught on to the additive effect of the repulsion of the EM charge of the protons. Once again, you've taught me something and made it very much worth my while to tune in, thanks :)

[PMA]

I spent 7 years in the nuclear industry and it doesn't make parties interesting. It just means people who think they know more than you try to convince you your safety work is all mistaken. And that's after a week of work when you want some time off.

[paulc]

Thanks (again) Arvin for another excellent video, explained clearly. Love the Velcro example for the SNF - I have seen it demonstrated once before, with Velcro glued onto 2 bar magnets, then the two same poles being forced together. Please keep them coming. Best wishes from West Wales, UK.

[shaunhayward]

I love your videos. I barely have a high school education but find it tremendously interesting. You present things to very well. Thank you so much!

[jaredhamilton]

The breadth of your value as a teacher can not be overstated. Whether I’m revisiting things that are familiar, or those that I am still learning, you are the pulsing magnetar from which the field of information propagates into minds such as mine which, as nature would have it, responds to the field in a different way than the preponderance of others.

So on behalf of all of those like myself, thank you for your unique attributes that bestow the force carriers of the field such that our minds may be bombarded by the quantum effects of the Arvinton field.

[andreyassa]

This video is amazing! To be conveniently ushered through all nuclear physics in such an educational and entertaining way, was quite impressive. I'm really grateful for you, producing always such enthralling content. On top you are such a kind and likeable person in my opinion, thanks a lot for all your effort!

[SSS-hrey]

Loved the video Arvin, best utilisation of 12 minutes I’ve experienced all week. Thanks

[Rationalific]

You give some of the very best scientific explanations out there! This relatively short video explained a ton and was super-entertaining as well! Keep up the great work!

[zack_]

6:35 - for easier memory, alpha particles/decay are emissions of helium nuclei, beta particles are electrons released from neutron decay into protons, and gamma particles are mass-less, high energy photons.

[anthonycarbone]

The video was very informative and explained some concepts that needed explaining so understanding could take place. Much of what was said was taken for granted like it needed no explanation but Arvin Ash drilled down into the details missing from any physic lesson I have ever attended. The funny part is I did not even realize the details needed further explanation!!!

[alphaomega]

Thanks! I can now add Nuclear Physicist to my resume. 😶

[andycopeland]

"Dangerously interesting at your next dinner party."

[Raintiger]

Wow. . this is hands down the best explanations I've seen. Thanks for expanding my understanding!

[rwarren]

All concepts were explained so clearly I don’t have any questions, just a certain smugness due to new knowledge.

[claudiorassouli]

Never knew that gamma radiation is the byproduct of the protons and neutron realigning itself in the nucleus. Another great video where I learn just a couple new things. Thank you for breaking it down for me.

[kayodave]

I find a good way to describe how ridiculously more powerful thermonuclear bombs are (hydrogen bombs) by pointing out, as Arvin says at 11:19, that a hydrogen bomb uses a fission bomb (i.e. the type of bombs used in WWII) as its TRIGGER. Imagine how much force it takes to squeeze the trigger of a gun vs how much damage a gun can do. That’s the kind of separation between the energy output of an atomic bomb vs a hydrogen bomb. Always awe inspiring and terrifying to think about.

[samorgan]

This is a treasure trove of a video, thank you!

[An_Attempt]

Beautiful, you have answered questions that I have had for years.

[Quadflash]

Wow! Dr. Ash, I have some conceptual understanding of the information you've presented here. As I watch your video (repeatedly), I'm awed by the flow and completeness of the information.

For background, I've been fascinated by nuclear and quantum physics for years -- lots of classes and reading on these subjects. (I'm certainly not expert)

I'm wondering what someone with little prior knowledge would find in this video? Wondering if many of your viewers would find a little pre-work useful before becoming seriously interesting people? 🌞