Pssst... we made flashcards to help you review the content in this episode! Find them on the free Crash Course App! Download it here for Apple Devices: apple.co/3d4eyZo Download it here for Android Devices: bit.ly/2SrDulJ
Nuclear physicist here, two quibbles with your video. First a small one : at 6:21 you say that beta decay has "higher energy" that alpha decay -- It hasn't. It does have higher range, or ability to penetrate matter, which is due to the electron being 8000 times lighter, and faster than an alpha for roughly the same energy. Second: GAMMA RADIATION IS NOT CAUSED BY ELECTRONS but by changes in the internal state of the nucleus (protons and neutrons jumping shells much as electrons do to emit light). X-rays can be emitted by core electrons following electron capture decay by the nucleus, but that's different and a very specific process. Gammas are emitted by the nucleus. It would be nice to correct this vid, to keep it up to the standard of previous ones. Thanks !
6:54 An error: Xe is element 54. Element 91 is Protactinium, which has an average mass of 231.03588 g/mol, which means that Pa-234 is an isotope which is heavier than average (meaning I suspect it will pretty soon decay as well).
Not only have all of these awesome chemistry videos caused me to fall in love with Hank, but they have also effectively prepared me for my chemistry semester final! THANK YOU CRASH COURSE!
Gamma rays are not generated by transition between electron levels. The energy difference is too small. Instead, they are generated by re-arrangement of protons and neutrons within the neucleus. They frequently modeled by shell model, too, although very different form the electric one.
As a Materials Scientist/Engineer, I just want to tell you how much I love these videos. They're so fun. Keep it up, Hank, the signed poster I got from Subbable goes up on the wall as soon as I can find a good frame!
Gamma rays can occur from pure nuclear state transitions without involving electrons at all, when one isomer decays into a more stable one. Generally we talk about Gamma rays only when there's some sort of nuclear process taking place and X-rays when the process involves electrons.
It's true, electron transitions simply do not come in big enough energy intervals to emit gamma rays. A 6s->1s transition in Barium emits an x-ray 20 times less energetic than the gamma ray emitted by the nucleus associated with the 137Cs->137Ba beta decay
I think it's a mestake too. besides wikipedia tells thorium dacay forms Ra or Pa (1 neutrom splitting in 1 proton + 1 electron). maybe they should have a nucrear phisic consultant beside a chemestry consultant.
+Vishvak Seenichamy There's actually an electron antineutrino wasn't shown in the beta decay equation. When the thorium atom decays, one neutron in the nucleus converts into a proton, an electron and an antineutrino. Hence after the decay the number of proton increases (the thorium atom turns into xenon atom) while the nucleon number stays the same (number of neutron reduces by 1).
+Raito Ng I find it a neccesity to correct the typo here. It says "One proton in the nucleus", but I know you meant "One neutron in the nucles converts into..". This was so that people reading your comment will be able to understand what was wrong and what's right. :) EDIT: According to this information the atomic number should increase by one from the original atomic number. So it should increase from Thorium-234 to Proctactinium-234. This is because the protons increase by 1 and 90+1=91, and the atom with 91 protons is Proctactinium and not Xenon. This was probably just a typo from the guys who made the video and they probably just forgot to do something about it. xD
Gamma radiation is released directly from the nucleus, not from excited electrons. It's called ionizing radiation for a reason - a gamma ray is powerful enough to knock any electron out of the atom entirely.
In the nuclear industry and in school, they use californium-252 as a neutron source. Never seen 254Cf... Also, although you can excite electrons into the energy ranges of nuclear gamma radiation (and vice versa), gamma rays are pretty generally a nuclear phenomenon. I appreciate this episode, but it would really be worth doing over a few segments.
Thank you for your great work! This is my go to channel for any chemistry subjects I need help with. I really enjoy your random dry humor it definitely helps me stay attentive! Keep it up!
Good video, guys. Many people have pointed out, that gamma rays originate from transitions within the nucleus. I agree with that but one should still mention that electron capture reactions, which are a variant of beta decays, lead to energetic photons being emitted by an electron. Nevertheless those photons are referred to as x-rays.
While electrons do emit photons when changing energy levels, this is simply fluorescence not gamma radiation. Gamma radiation is created when the nucleus relaxes from an excited state.
Gamma radiation is a wave, just like light is. Photons are force carriers that act like waves and particles. So depending on the element and energy level, an electron could give off Gamma radiation. Plus, if you think photons are just visible light(fluorescence), you're an idiot. All EMR (electromagnetic radiation which is carried by photons) can be emitted from electrons falling down a level state, which includes all the types said in the video but also includes radiowaves, and X rays. Just depends on initial energy state of electron and where it rests. Please, educate yourself before making mindless comments like you did
Alex is referencing the part of the video that explains gamma decay as the release of photons from electrons as they transition to lower energy states. While electrons can release gamma photons, the problem is that electrons are not the source of gamma photons during gamma decay--Alex is correct in stating that the gamma photons originate in the NUCLEUS as it relaxes from an excited state. Plus, fluorescence does not only refer to visible light--it's just refers to things that can only emit light by absorbing light first. And the term can be applied to what happens when electrons absorb and then release photons. More specifically, it's called resonance fluorescence when referring to atomic spectra, but it's still a type of fluorescence.
Parker Stromberg I am well aware of what the electromagnetic spectrum is. Although they historically have been differentiated by wavelength, the modern convention actually is to distinguish between x-rays and gamma rays based on their source. This means there is some overlap between the energy ranges of x-rays and gamma rays. But to be clear the video is talking about gamma decay which occurs in the nucleous, and has nothing to do with the energy levels of electrons.
Hi guys, I love the videos! One issue is you're not on the mark for gamma decay. This is similar to excited electronic state de-excitation but it is actually nuclear energy levels of protons or neutrons falling to the ground state in the nucleus. I am a professor of nuclear chemistry btw
It would be awesome if Crash Course made quizlets (google quizlet if you haven't heard of it) to accompany some of their lessons. Not that you don't already offer enough for free. Maybe viewers could help make quizlets for the videos.
There are various errors here. Firstly, a beta particle can be an electron or positron, not just electron. Secondly gamma decay occurs from the NUCLEUS when the NUCLEUS is unstable. It has nothing to do with the electron energy state. Lastly, the fact that gamma rays are the most penetrative is the reason why they are the least harmful compared to cells absorbing alpha or beta particles
At 7:25, you say that gamma decay is the transition of an electron in the shell to a lower energy state, but it's not. It's the transition of the core, to a lower energy state formation.
Many people likes to learn things online. Please make sure there are no mistakes in it. In this one I observed two mistakes 1) Thorium when emits electron decays into Palladium. 2) Gamma rays are emitted not due to electron transition but when a nucleus gives out it's excited energy.
yes gamma rays are the most dangerous in a way (especially when you arent coming into close contact with the form of radiation) because it can penetrate your skin, but if you ate something containing alpha particles it would be far more harmful, because they wont be able to escape your body and will just go around ionising your cells until you die nice and beta is also dangerous (and did you mention beta + decay? or the formulae for them? like how ß- is when n--> p + e- + anti electron neutrino and ß+ is when p --> n + e+ + electron neutrino)
John, you made a little mistake: Gamma-decay comes from nuclei changing states. When electron emits high energy radiations because they change states its called x-rays,
These videos are just amazing. I've been amusing myself quite a long time now with binge-watching Crash Courses on all kinds of subjects. It truly answers a lot of interesting questions that don't get enough attention in class!
Half way through this video i hear the crash course theme playing from my kitchen. I pause and shout, "MOM ARE YOU WATCHING A CRASH COURSE VIDEO?!?" She replied with, "YEAH I'M WATCHING ONE ON THE DIGESTIVE SYSYEM." To which I replied with, "I'M WATCHING A CRASH COUSE ON NUCLEAR CHEMISTRY!"
Since when did Thorium decay straight into Xenon via Beta radiation? Thorium decays to Protactinium this way, and Xenon's atomic number is 58. Not quite sure how this happened, but it's a brilliant video anyways.
Thanks for the video, but you should replace it with a corrected one that does not have Gamma radiation being emitted by excited electrons. Gamma radiation is emitted by the nucleus.
When your teacher just asigns videos for you to watch during online school and you break your computer because the video is worse than your actual teacher
When you discuss gamma radiation, you talk about electrons being in an excited state. I know that's how much visible and near-visible light is emitted, but for nuclear gamma radiation isn't it that the nuclear arrangement of protons and neutrons is in a higher-energy excited state?
Hey anthony, if you drive a car every day, then you're risking your life. It's worth it though, just like nuclear energy. Don't you think if more people learn about nuclear science, we are more likely to make it safer?
Hello mr.Green, Could you make some videos about volcanos, earthquakes etc when you finish the chemistry? It'd be very helpful, you're a very good teacher. Greetings from Italy.
Aeroscience The answer is basically in the name. Nuclear Chemistry deals with the chemical components of the of the nuclear particles such as plutonium and uranium. Nuclear Physics really deals with how everything is going to work out. When building a nuclear reactor, you need both scientists working closely with each other to make sure everything runs smoothly and no incidents happen in the present or in the future.
I see. It's just, when I took chemistry, they had a unit on "nuclear chemistry", and when I took physics, they had a unit on "nuclear physics". But they covered the exact same material.
Aeroscience When you get into more complicated sciences, you will see that there are differences. A simple way to see the difference is this quote from yahoo answers which I strongly agree with."nuclear physics explain the components involved in nuclear reaction. nuclear chemistry explains how the reaction happens between the components." -v_chaitan
I think this subject is a great idea to tackle because general population really has no clue about it. Just one tiny correction - gamma rays or any other photons aren't "pure energy". Energy is the ability to do work. Photons are particles that carry energy. The fact that they go at the speed of light and cease to exist after absorption is something different. Anyway, great work. I'm looking forward to see the second part. Suggestion - if you talk about uranium, or any other element or compound, bring it and show it to the camera.
Unsurprisingly substandard. Nuclear physics cannot be done in a 10-minute video by chemists. No offence, guys, but you have a number of unclarities and outright mistakes this time. Gamma rays are not emitted by electrons, ionizing radiation does not ever add electrons (it may break a molecule into a positive and a negative ion but will never actually add an electron, which has nowhere to come from in non-ionized matter anyway) and Thorium into Xenon via beta-decay... I hate thumbing down videos from people I like but this one needs to go down. Late P.S. Comment is intentionally harsher than I'd normally write. Further explanation bellow.
You seem to be hating too much on free education for anyone with Internet. All of Crash Course's videos have been around 10 minutes long. The goal of this isn't to give you the precise mathematical calculations that are associated with chemistry, it is used to give the concepts in an easy to grasp way. Also, gamma radiation CAN be emitted by electrons when a particle decays. Take Cobalt-60 for example. After the particle decays, it becomes an excited Nickel which gives off gamma radiation because of its electrons. So before you start hating on these videos, a simple Google search could alleviate most of your points.
chaos101011 actually if YOU bothered to do any research, you'd see that gamma rays, by definition, are emitted from the nucleus, distinguishing themselves from xrays. lowstef was right, they did not do a lot of research for this topic and made some very basic mistakes.
chaos101011 This is one of those weird definition things I think. If you're a nuclear physicist a gamma ray is produced by transitions within nuclear shell structure (it's analogous to shells and sub-shells with some of its own peculiarities) and x-rays are produced by electron transitions. This sometimes means you'll have x-rays with higher energies than gamma-rays. If you're an astrophysicist (and probably anyone else, but this is more my field) then gamma-rays are defined as any photon with energy higher than the rest mass of an election (~511MeV), with x-rays being the bit between ultraviolet and that energy.
Hold on. Thorium-234 decays into Protactinium-234m and definitely not Xenon-234, for two main reasons: Xenon-234 doesn't exist in any form, and Xenon's atomic number is 54 not 91, so the only way it would do that would be through trihextuple positron decay, which is completely impossible, since anything more than double is quite implausible, and would cause a huge amount of radiation. Also you should at least say that there are more types of radiation, but that you don't have time to talk about things like neutron decay, electron and neutron capture, and hypothetical things like proton decay. I knew this, and I'm only 15 (although I am the top of my class in chemistry), however it doesn't bother me much because the other episodes have been excellent, and I understand how difficult it is to explain everything in 10 minutes.
Usually your videos are great Hank, but I think you've been iffy on the definition of gamma radiation. While everywhere gamma rays are just a form of EM wave with an energy higher than a certain energy and CAN be produced by electron transitions in this case the more relevant definition is (I think) that those are EM waves produced IN the nucleus given that you're talking about nuclear physics. You should perhaps also have explained beta plus and beta minus decay since they differ greatly. But otherwise, given the 10 minutes I think this is great!
I'd love to know how many Jr, Sr high & city college teachers/instructors have incorporated these videos into their lessons. Not only are these fun to watch, but they're easily digestible. Those two factors combined with them simply being published on TH-cam, I would think Millennials would relate to these easier. As well as, understand them as their production is fantastic and explanations are top notch.
Great series, but I'm disappointed at the mistakes in this episode: 1) Thorium-234 decays into Protactinium-234m not Xenon 2) Gamma rays are not produced by movement of electrons, but by nucleons. (Electrons produce x rays) 3)Secondary gamma rays are not the result of the parent being in a exited state prior to decay (although it's possible), but by excess energy released as a result of the primary decay.
I did find it kind of odd hearing electrons returning to their ground causing gamma rays. Generally gamma rays are associated with nuclear transitions, x-rays are associated with core electronic transitions, and UV and visible light are associated with valance electronic transition.
Yeah, that's an inaccuracy. Though, "photons"/"gamma rays" are often used interchangebly, i.e. even when the photons are produced in ways other that nuclear transitions.
Hi, I really love your show but as a physicist, I must point an error... The second type of radiation isn't an electron, is an anti-positron, this particle have all the proprieties of the positron but the sign of the charge and has the mass of -1 because it's necessary produce 1 proton to produce an anti-proton, so you gain 1 proton for each anti-proton Ps. I make a mistake changing the particles... anti-protons have mass of a proton, beta particle have a very tine mass... see the comments bellow... The beta particle is indeed an electron
Beta radiation isn't anti-protons though - β− emissions are electrons, and β+ emissions are positrons. The proton number increases by one because a neutron becomes a proton in β− decay.
You are right... If the beta particle was an anti-positron it should be mass, the illusion of knowledge is a dangerous thing. I should have checked this information before posting, thanks for correcting me... Indeed beta particles could be positrons as well when a proton decay into a neutron and a beta+ particle, but the beta- (electron) is more common, by the fact that a neutron have more mass than an proton.
Now, I love my science teacher, but he really did not explain this well... thank you so much; I can actually do my work now!!! Also was anyone else slightly distracted by how awesome Hank's shirt is?
Dear. crash course I wanted to make a quick suggestion for an episode. I think a topic of glass is well in order. From its four thousand year old history to its mundane uses in the home. Glass has been a part of almost every scientific achievement. We would not be where we are today without it. I think that alone would warrant an episode. But when you add on top of that the enigma that is around glass in the scientific community despite its prevalence is too much to overlook. I think with a tiny bit of research you will come to appreciate my position, and hopefully will find it fascinating enough to make an episode. I would like to thank you for all your hard work and for taking your time to read this I hope you consider my suggestion.
Recommendations for watching crash course: 1. Take notes when you watch the video 2. Pause the video and replay if you don't understand something 3. Set the speed to 0.75. This makes it much easier to understand
I wish you would show the actual process of how the math works with half-life. But thank you for your help. I will watch this over and over again till my exam tomorrow.
Yeah, no... you should have a nuclear physicist proof-read this episode again. While this is probably okay and sufficient for many a chemist, there are some factual errors in there.
Great video with plenty of good explanations but the Gamma emission explanation was wrong as well as a few other minor points. This may be a video that you guys should re-edit to correct the mistakes since they are very misleading and can cause some serious confusion.
Pssst... we made flashcards to help you review the content in this episode! Find them on the free Crash Course App!
Download it here for Apple Devices: apple.co/3d4eyZo
Download it here for Android Devices: bit.ly/2SrDulJ
spicy air
k
All hail Crash Course. Please don't stop making videos at least until I'm out of high school.
graduate yet?
graduate yet?
crazy to think ur out already. i’m a sophomore smh
@@nicole4502 junior
Why are you learning about this in high school? Lol
Nuclear physicist here, two quibbles with your video. First a small one : at 6:21 you say that beta decay has "higher energy" that alpha decay -- It hasn't. It does have higher range, or ability to penetrate matter, which is due to the electron being 8000 times lighter, and faster than an alpha for roughly the same energy. Second: GAMMA RADIATION IS NOT CAUSED BY ELECTRONS but by changes in the internal state of the nucleus (protons and neutrons jumping shells much as electrons do to emit light). X-rays can be emitted by core electrons following electron capture decay by the nucleus, but that's different and a very specific process. Gammas are emitted by the nucleus. It would be nice to correct this vid, to keep it up to the standard of previous ones. Thanks !
Fascinating to see a nuclear physicist, I’m only an 8th grader working on a nuclear chemistry project lol
K
You probably cringe at fallout lol
@@twistiicuber1055 Im 12 in 7th grade, I'm just interested in this because it seems cool, which it is.
@Loading_101 cool
if you think about it, radioactivity is just...
*S P I C Y A I R*
@MAHALAKSHMI PERUMAL why thank you.
this is the greatest thing ive ever read
You made me laugh so hard! Thank you!
@@uniqhnd23 Does it count that I'm dead *inside?*
wowzers
6:54 An error: Xe is element 54. Element 91 is Protactinium, which has an average mass of 231.03588 g/mol, which means that Pa-234 is an isotope which is heavier than average (meaning I suspect it will pretty soon decay as well).
Not only have all of these awesome chemistry videos caused me to fall in love with Hank, but they have also effectively prepared me for my chemistry semester final! THANK YOU CRASH COURSE!
This is awesome. More evidence that we are living in exponential and information rich times. Keep the knowledge coming!
I've been hoping we would cover nuclear chemistry!!! This is my all time favorite topic. Nuclear pharmacy is like my dream job.
dude you're incredibly helpful but talk so so so fast I can't process what you're saying.
put it at 0.5 speed
putting it at 2 speed is hilarious
I put it at 1.25 so i can understand xD
I had the same problem but 0.5 speed is too slow so put it 0.75 speed
wow thats hilarious
Gamma rays are not generated by transition between electron levels.
The energy difference is too small.
Instead, they are generated by re-arrangement of protons and neutrons within the neucleus. They frequently modeled by shell model, too, although very different form the electric one.
This topic is not easy to process and for him to talk that fast makes it even harder to comprehend.
As a Materials Scientist/Engineer, I just want to tell you how much I love these videos. They're so fun. Keep it up, Hank, the signed poster I got from Subbable goes up on the wall as soon as I can find a good frame!
Love the Imagine Dragons reference!
Gamma rays can occur from pure nuclear state transitions without involving electrons at all, when one isomer decays into a more stable one. Generally we talk about Gamma rays only when there's some sort of nuclear process taking place and X-rays when the process involves electrons.
True. Electrons giving off gamma photons aren't exactly something you hear when you learn about gamma radiation. Nucleus does that job.
It's true, electron transitions simply do not come in big enough energy intervals to emit gamma rays. A 6s->1s transition in Barium emits an x-ray 20 times less energetic than the gamma ray emitted by the nucleus associated with the 137Cs->137Ba beta decay
If Thorium-234 loses a beta particle, shouldn't it become Protactinium-234? Xenon only has 54 protons.
I think it's a mestake too. besides wikipedia tells thorium dacay forms Ra or Pa (1 neutrom splitting in 1 proton + 1 electron). maybe they should have a nucrear phisic consultant beside a chemestry consultant.
You are correct. This is a mistake.
Yes, it is an error
I love radioactive!
And nice minecraft reference.
At 6:53, how come it Xenon has a number of 91 when Thorium had 90 and when it released it's electron?
+Vishvak Seenichamy
i think it should be Protactinium (Pa) because thats number 91.
+Vishvak Seenichamy no no no a neutron turns itself into a proton releasing an electron
+Vishvak Seenichamy
There's actually an electron antineutrino wasn't shown in the beta decay equation.
When the thorium atom decays, one neutron in the nucleus converts into a proton, an electron and an antineutrino. Hence after the decay the number of proton increases (the thorium atom turns into xenon atom) while the nucleon number stays the same (number of neutron reduces by 1).
+Raito Ng I find it a neccesity to correct the typo here. It says "One proton in the nucleus", but I know you meant "One neutron in the nucles converts into..". This was so that people reading your comment will be able to understand what was wrong and what's right. :)
EDIT:
According to this information the atomic number should increase by one from the original atomic number. So it should increase from Thorium-234 to Proctactinium-234. This is because the protons increase by 1 and 90+1=91, and the atom with 91 protons is Proctactinium and not Xenon. This was probably just a typo from the guys who made the video and they probably just forgot to do something about it. xD
Didn't realize it. Thanks a lot xP
This is the branch of chemistry that I find the most exciting.
Omg. I've finally seen someone make a reference to the Mutant Zombie from Minecraft!
Gamma radiation is released directly from the nucleus, not from excited electrons. It's called ionizing radiation for a reason - a gamma ray is powerful enough to knock any electron out of the atom entirely.
In the nuclear industry and in school, they use californium-252 as a neutron source. Never seen 254Cf...
Also, although you can excite electrons into the energy ranges of nuclear gamma radiation (and vice versa), gamma rays are pretty generally a nuclear phenomenon.
I appreciate this episode, but it would really be worth doing over a few segments.
this guy knows everything
Please do Crash Course Physics!
Hole. y. Shit. YES!!!!
+Random Tech Videos You could go to khan academy
they have one now
+Random Tech Videos It just did *TODAY* FINALLY YES!!!!!!!!!!!!!!!!!!!
Random Tech Videos that would be sho helpful
So, the half-life of Bismuth is 7.7 Septillion years. (7,700,000,000,000,000,000,000,000)
BRUUUUUHHHH
DID SOMEONE SAY HALF-LIFE!?
yes half-life refers to the time it takes for an element to reach half of it's lifespan
an g I don't think you got the reference
A HALF-LIFE OF 3 SECONDS?
halflife 3 confirmed
Lord GabeN Lord Gaben, enlighten us by Confirming Half life 3.
Thank you for your great work! This is my go to channel for any chemistry subjects I need help with. I really enjoy your random dry humor it definitely helps me stay attentive! Keep it up!
0:09 WHOA-OH OH I’M, WHOA-OH OH I’M, RADIOACTIVE, RADIOACTIVE
He’ll yeah
That intro was the single best thing I have ever seen or imagined seeing ever
I had a test on this on friday, looked everywhere for a radioactivity video and of course its posted just 3 short days later -_-
I got covid and had to miss a whole week of university chemistry lectures, you're saving my butt once again, Hank!
Good video, guys. Many people have pointed out, that gamma rays originate from transitions within the nucleus. I agree with that but one should still mention that electron capture reactions, which are a variant of beta decays, lead to energetic photons being emitted by an electron. Nevertheless those photons are referred to as x-rays.
While electrons do emit photons when changing energy levels, this is simply fluorescence not gamma radiation. Gamma radiation is created when the nucleus relaxes from an excited state.
YESSSS. Glad someone else caught that.
Gamma radiation is a wave, just like light is. Photons are force carriers that act like waves and particles. So depending on the element and energy level, an electron could give off Gamma radiation. Plus, if you think photons are just visible light(fluorescence), you're an idiot. All EMR (electromagnetic radiation which is carried by photons) can be emitted from electrons falling down a level state, which includes all the types said in the video but also includes radiowaves, and X rays. Just depends on initial energy state of electron and where it rests. Please, educate yourself before making mindless comments like you did
Alex is referencing the part of the video that explains gamma decay as the release of photons from electrons as they transition to lower energy states. While electrons can release gamma photons, the problem is that electrons are not the source of gamma photons during gamma decay--Alex is correct in stating that the gamma photons originate in the NUCLEUS as it relaxes from an excited state. Plus, fluorescence does not only refer to visible light--it's just refers to things that can only emit light by absorbing light first. And the term can be applied to what happens when electrons absorb and then release photons. More specifically, it's called resonance fluorescence when referring to atomic spectra, but it's still a type of fluorescence.
Parker Stromberg I am well aware of what the electromagnetic spectrum is. Although they historically have been differentiated by wavelength, the modern convention actually is to distinguish between x-rays and gamma rays based on their source. This means there is some overlap between the energy ranges of x-rays and gamma rays.
But to be clear the video is talking about gamma decay which occurs in the nucleous, and has nothing to do with the energy levels of electrons.
+Kathryn Stone I see what you guys mean now. Sorry about that
Hi guys, I love the videos! One issue is you're not on the mark for gamma decay. This is similar to excited electronic state de-excitation but it is actually nuclear energy levels of protons or neutrons falling to the ground state in the nucleus. I am a professor of nuclear chemistry btw
For Those Who Dont Know The First Song Actually Was Radioactive-Imagine Dragons
There was a typo! At 5:55, it should not be Xe, it should be the element Pa.
Grammar Nazi
No
Chemistry nazi
Andrea Liu, There isn't even an Xe in there, Idk what you're talking about... Helium (He) is in there! But there's no Xenon (Xe) in there.
Wrong time. It is 6:39
I KNEW SOMETHING WAS WRONG I WAS SO CONFUSED
I literally just had a chemistry exam about this on Friday... this would been so helpful! ._.
It would be awesome if Crash Course made quizlets (google quizlet if you haven't heard of it) to accompany some of their lessons. Not that you don't already offer enough for free. Maybe viewers could help make quizlets for the videos.
Thank you for making it seem way less crazy when I tell my coworkers that I learned how to make yellow cake at home. :)
I love how this simplifies otherwise complex information, schools need to be taught like this
HANK mentioned Imagine dragons!!! my life is complete.
There are various errors here. Firstly, a beta particle can be an electron or positron, not just electron. Secondly gamma decay occurs from the NUCLEUS when the NUCLEUS is unstable. It has nothing to do with the electron energy state. Lastly, the fact that gamma rays are the most penetrative is the reason why they are the least harmful compared to cells absorbing alpha or beta particles
At 7:25, you say that gamma decay is the transition of an electron in the shell to a lower energy state, but it's not. It's the transition of the core, to a lower energy state formation.
Many people likes to learn things online. Please make sure there are no mistakes in it. In this one I observed two mistakes 1) Thorium when emits electron decays into Palladium. 2) Gamma rays are emitted not due to electron transition but when a nucleus gives out it's excited energy.
You missed out the anti-neutrino in the beta minus decay equation.
yes gamma rays are the most dangerous in a way (especially when you arent coming into close contact with the form of radiation) because it can penetrate your skin, but if you ate something containing alpha particles it would be far more harmful, because they wont be able to escape your body and will just go around ionising your cells until you die
nice
and beta is also dangerous
(and did you mention beta + decay? or the formulae for them? like how ß- is when n--> p + e- + anti electron neutrino and ß+ is when p --> n + e+ + electron neutrino)
John, you made a little mistake: Gamma-decay comes from nuclei changing states. When electron emits high energy radiations because they change states its called x-rays,
you mean Hank?
yep
These videos are just amazing. I've been amusing myself quite a long time now with binge-watching Crash Courses on all kinds of subjects. It truly answers a lot of interesting questions that don't get enough attention in class!
HANK GREEN MADE AN IMAGINE DRAGONS REFERENCE
my life is literally complete
It feels somber learning about radioactivity now.....best wishes with your treatment ❤❤❤
He didn't say Nucular. I'm so happy.
Literally just about to write a paper about Arsenic 74. This really helped me understand the concept of nuclear chemistry! Thank you!
Half way through this video i hear the crash course theme playing from my kitchen. I pause and shout, "MOM ARE YOU WATCHING A CRASH COURSE VIDEO?!?" She replied with, "YEAH I'M WATCHING ONE ON THE DIGESTIVE SYSYEM." To which I replied with, "I'M WATCHING A CRASH COUSE ON NUCLEAR CHEMISTRY!"
0:30 I bring you peace! I bring you love!
ITS BRINGING LOVE DONT LET IT GET AWAY
BREAK ITS LEGS
Since when did Thorium decay straight into Xenon via Beta radiation? Thorium decays to Protactinium this way, and Xenon's atomic number is 58. Not quite sure how this happened, but it's a brilliant video anyways.
Thanks for the video, but you should replace it with a corrected one that does not have Gamma radiation being emitted by excited electrons. Gamma radiation is emitted by the nucleus.
When your teacher just asigns videos for you to watch during online school and you break your computer because the video is worse than your actual teacher
When you discuss gamma radiation, you talk about electrons being in an excited state. I know that's how much visible and near-visible light is emitted, but for nuclear gamma radiation isn't it that the nuclear arrangement of protons and neutrons is in a higher-energy excited state?
Hey anthony, if you drive a car every day, then you're risking your life. It's worth it though, just like nuclear energy. Don't you think if more people learn about nuclear science, we are more likely to make it safer?
Just want to say I've watched most of these videos for my ap test tomorrow and watching these has been most helpful.
bruh we’re watching you in class as classwork
In gamma decay, the nucleus goes from an excited state to a ground state, not an electron.
Hello mr.Green,
Could you make some videos about volcanos, earthquakes etc when you finish the chemistry? It'd be very helpful, you're a very good teacher. Greetings from Italy.
🎲🌋
@ 3:40
"Hello Gordon!"
What's the difference between nuclear chemistry and nuclear physics?
Aeroscience The answer is basically in the name. Nuclear Chemistry deals with the chemical components of the of the nuclear particles such as plutonium and uranium. Nuclear Physics really deals with how everything is going to work out. When building a nuclear reactor, you need both scientists working closely with each other to make sure everything runs smoothly and no incidents happen in the present or in the future.
I see. It's just, when I took chemistry, they had a unit on "nuclear chemistry", and when I took physics, they had a unit on "nuclear physics". But they covered the exact same material.
Aeroscience When you get into more complicated sciences, you will see that there are differences. A simple way to see the difference is this quote from yahoo answers which I strongly agree with."nuclear physics explain the components involved in nuclear reaction.
nuclear chemistry explains how the reaction happens between the components."
-v_chaitan
I see, thank you for clarifying.
Aeroscience Honestly, I'd call this nuclear physics, as presented.
I think this subject is a great idea to tackle because general population really has no clue about it.
Just one tiny correction - gamma rays or any other photons aren't "pure energy". Energy is the ability to do work. Photons are particles that carry energy. The fact that they go at the speed of light and cease to exist after absorption is something different.
Anyway, great work. I'm looking forward to see the second part.
Suggestion - if you talk about uranium, or any other element or compound, bring it and show it to the camera.
Unsurprisingly substandard. Nuclear physics cannot be done in a 10-minute video by chemists. No offence, guys, but you have a number of unclarities and outright mistakes this time. Gamma rays are not emitted by electrons, ionizing radiation does not ever add electrons (it may break a molecule into a positive and a negative ion but will never actually add an electron, which has nowhere to come from in non-ionized matter anyway) and Thorium into Xenon via beta-decay... I hate thumbing down videos from people I like but this one needs to go down.
Late P.S. Comment is intentionally harsher than I'd normally write. Further explanation bellow.
You seem to be hating too much on free education for anyone with Internet. All of Crash Course's videos have been around 10 minutes long. The goal of this isn't to give you the precise mathematical calculations that are associated with chemistry, it is used to give the concepts in an easy to grasp way.
Also, gamma radiation CAN be emitted by electrons when a particle decays. Take Cobalt-60 for example. After the particle decays, it becomes an excited Nickel which gives off gamma radiation because of its electrons. So before you start hating on these videos, a simple Google search could alleviate most of your points.
chaos101011 There's a big difference between hating on a video and giving it constructive criticism.
Tyranisaur no....this is pretty far from constructive criticism
chaos101011
actually if YOU bothered to do any research, you'd see that gamma rays, by definition, are emitted from the nucleus, distinguishing themselves from xrays.
lowstef was right, they did not do a lot of research for this topic and made some very basic mistakes.
chaos101011 This is one of those weird definition things I think.
If you're a nuclear physicist a gamma ray is produced by transitions within nuclear shell structure (it's analogous to shells and sub-shells with some of its own peculiarities) and x-rays are produced by electron transitions. This sometimes means you'll have x-rays with higher energies than gamma-rays.
If you're an astrophysicist (and probably anyone else, but this is more my field) then gamma-rays are defined as any photon with energy higher than the rest mass of an election (~511MeV), with x-rays being the bit between ultraviolet and that energy.
Omg I just happened to need this for next Monday's task!:O THANKS!
Hold on. Thorium-234 decays into Protactinium-234m and definitely not Xenon-234, for two main reasons: Xenon-234 doesn't exist in any form, and Xenon's atomic number is 54 not 91, so the only way it would do that would be through trihextuple positron decay, which is completely impossible, since anything more than double is quite implausible, and would cause a huge amount of radiation. Also you should at least say that there are more types of radiation, but that you don't have time to talk about things like neutron decay, electron and neutron capture, and hypothetical things like proton decay. I knew this, and I'm only 15 (although I am the top of my class in chemistry), however it doesn't bother me much because the other episodes have been excellent, and I understand how difficult it is to explain everything in 10 minutes.
Shouldn't the gamma decay be produced from excited nucleus energy levels, not election energy levels?
This is the most viewed episode since the first
These videos are brilliant
Usually your videos are great Hank, but I think you've been iffy on the definition of gamma radiation. While everywhere gamma rays are just a form of EM wave with an energy higher than a certain energy and CAN be produced by electron transitions in this case the more relevant definition is (I think) that those are EM waves produced IN the nucleus given that you're talking about nuclear physics. You should perhaps also have explained beta plus and beta minus decay since they differ greatly. But otherwise, given the 10 minutes I think this is great!
I'd love to know how many Jr, Sr high & city college teachers/instructors have incorporated these videos into their lessons.
Not only are these fun to watch, but they're easily digestible. Those two factors combined with them simply being published on TH-cam, I would think Millennials would relate to these easier. As well as, understand them as their production is fantastic and explanations are top notch.
Perhaps a video of the industrial uses, and the types of sources used would be a good idea.
LOVE it for so many reasons but the biggies for me were Xe and at 9:10 should have 6 neutrons (along with a full notation showing mass and charge)
Great series, but I'm disappointed at the mistakes in this episode:
1) Thorium-234 decays into Protactinium-234m not Xenon
2) Gamma rays are not produced by movement of electrons, but by nucleons. (Electrons produce x rays)
3)Secondary gamma rays are not the result of the parent being in a exited state prior to decay (although it's possible), but by excess energy released as a result of the primary decay.
I did find it kind of odd hearing electrons returning to their ground causing gamma rays. Generally gamma rays are associated with nuclear transitions, x-rays are associated with core electronic transitions, and UV and visible light are associated with valance electronic transition.
"You seem to have brought your clever pants today" That sass lol
From what I’ve learned in school. I’ve had a discord conversation that taught me more than an entire semester.
nice editing dude! loved the video, learnt a lot, taught me more than my old teacher, Thanks!
Like if you think that a Crash Course/ Thought Cafe periodic table with the little elements doodles guys would awesome.
hmmmmm...
Thanks
Aren't most gamma rays produced by nuclear transitions rather than electron transitions? 100 keV is a lot of energy for an electron transition.
Yeah, that's an inaccuracy. Though, "photons"/"gamma rays" are often used interchangebly, i.e. even when the photons are produced in ways other that nuclear transitions.
This was awesome, I think I finally starting to understand Nuclear Chemistry.
"Now You've heard of Half Life"
a hahahaha ! Yes, i'm new!
6:40 it is protactinium
Hi, I really love your show but as a physicist, I must point an error... The second type of radiation isn't an electron, is an anti-positron, this particle have all the proprieties of the positron but the sign of the charge and has the mass of -1 because it's necessary produce 1 proton to produce an anti-proton, so you gain 1 proton for each anti-proton
Ps. I make a mistake changing the particles... anti-protons have mass of a proton, beta particle have a very tine mass... see the comments bellow...
The beta particle is indeed an electron
A positron is just an anti-electron, so an anti-positron is another name for an electron
Ohhh, sorry, I made a mistake when I write the post. Every positron in my post change by proton... Any positron is created in an radioactive reaction
Beta radiation isn't anti-protons though - β− emissions are electrons, and β+ emissions are positrons. The proton number increases by one because a neutron becomes a proton in β− decay.
Cesar Cícero if I'm not mistaken, you can edit your comments now. Try it out!
You are right... If the beta particle was an anti-positron it should be mass, the illusion of knowledge is a dangerous thing. I should have checked this information before posting, thanks for correcting me... Indeed beta particles could be positrons as well when a proton decay into a neutron and a beta+ particle, but the beta- (electron) is more common, by the fact that a neutron have more mass than an proton.
Thank you. As an 11th grader taking Chemistry Honors this is very helpful
Xenon 91?! - Do you really mean Protactinium 91?
Now, I love my science teacher, but he really did not explain this well... thank you so much; I can actually do my work now!!! Also was anyone else slightly distracted by how awesome Hank's shirt is?
Why is he racing 🏁😵
Dear. crash course
I wanted to make a quick suggestion for an episode. I think a topic of glass is well in order. From its four thousand year old history to its mundane uses in the home. Glass has been a part of almost every scientific achievement. We would not be where we are today without it. I think that alone would warrant an episode. But when you add on top of that the enigma that is around glass in the scientific community despite its prevalence is too much to overlook. I think with a tiny bit of research you will come to appreciate my position, and hopefully will find it fascinating enough to make an episode.
I would like to thank you for all your hard work and for taking your time to read this I hope you consider my suggestion.
and while they're at it, they could mention metallic glasses. because they're (both) awesome
OMFG IMAGINE DRAGONS REFERENCE THOUGH IM LAUGHING
(1:14) Totally wanted mutant Hank to be holding a mop in his hand a la Toxic Avenger.
Recommendations for watching crash course:
1. Take notes when you watch the video
2. Pause the video and replay if you don't understand something
3. Set the speed to 0.75. This makes it much easier to understand
I wish you would show the actual process of how the math works with half-life. But thank you for your help. I will watch this over and over again till my exam tomorrow.
Doesn't Xenon (Xe) have proton number of 54 not 91 which is Protactinium (Pa)?
Q. Define Hulk.
Ans. A giant green rage monster that doesn't obeys law of conservation of mass.
But, energy and mass are inter-convertible.
Yeah, no... you should have a nuclear physicist proof-read this episode again. While this is probably okay and sufficient for many a chemist, there are some factual errors in there.
Mention some please
this is an introductory video to nuclear chemistry
Great video with plenty of good explanations but the Gamma emission explanation was wrong as well as a few other minor points. This may be a video that you guys should re-edit to correct the mistakes since they are very misleading and can cause some serious confusion.
He said half-life multiple times, that's Half-Life 3 confirmed!!!!