Black Bodies and Planck Explained

Explaining the theory behind black body radiation, the problems it caused in terms of classical theory, and Max Planck's solution
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[@izzyy319]

All this time I've been hating physics but I watched this video and was blown away. It all makes sense now. Thanks so much!!

[@bipolatelly9806]

Isabel Curtis Then you will LOVE the Thunderbolts Project. THE science channel on utoob!

[@shupesmerga4694]

IMO, the lack of context in the way of educating the kids makes these subjects difficult

[@juliusraben3526]

Sad that your school physics teachers couldnt do what this video did...... (it definitley made maths easier for me xD)

[@PhysicsHigh]

Glad it helped.

[@sauroman1]

Math is also boring. But make physics visual and easily understandable to imagination and it gets whole new meaning.

[@yoinkling]

Oh okay, I don't have to be confused about "why" because "why" isn't explained by Plank! what a relief

[@Danny-hj2qg]

(2:28) Correction, you're getting the smaller wavelengths in the blue/violet region of the visible spectrum, not the "frequencies" like you said.

[@reindeerchai1286]

The stair and slope example was brilliant! Thanks : D

[@coppercrusader6791]

im in graduate school haha the HIGH school physics explained makes me feel so dumb

[@mahathirmoon5010]

cause you are

[@tetestoes5188]

@@mahathirmoon5010 mean

[@mahathirmoon5010]

@@tetestoes5188 that's okay

[@tetestoes5188]

@@mahathirmoon5010 nah what if that person is sensitive

[@123bluestorm1]

@@mahathirmoon5010 dude wtf. Stop insulting people especially when u saved videos of UNDERSTANDING SLOPE and INTERPRETING DOT PRODUCT. The former even a middle schooler can understand, the latter a decent high schooler would get. If this guy is in grad school he’s prob much more smarter than you, a person who needs help understanding middle school maths.

[@shupesmerga4694]

Great explanation, subjects are easily understood when they don't depart from the context, it keeps the chain of thought connected and your attention continuous. Story-telling at it's finest.

[@friendlyman4729]

Honestly you are a saviour to my atar

[@xapk]

Hi, working my way through some early universe cosmology and need to understand some basic concepts more clearly.....so this is perfect! Thanks for your generous time!

[@danielsteinbrecher8339]

Thank you so much for keeping this topic to the basics so one can understand the central principal! Not one German video I saw did it as well as you did.

[@viharakumarasinghe8884]

As always your videos are amazing. Thank you so much for creating them. This is perfectly clear, simple and very easy to understand.

[@almirbravin1]

Its is the best explanation I've found at the level of high school , congratulations teacher.

[@michelleluulam472]

sir you are great

[@PhysicsHigh]

thank you - glad it helped

[@gearhead1302]

I was having a hard time fully understanding this and now I get it! Thanks.

[@shreyakalkundri137]

It was too good... I really understood everything.... Thank you so much

[@anthroexile]

Brilliant!!!! Thank you very much!

[@brianbycroft6090]

Am I missing something? As E = hf, more strictly speaking energy is only quantised for a particular emr frequency. As far as I'm aware, f is continuous??

[@Felhek]

You never say how Planck found the value of h. No one ever does i noticed. It seems nobody knows how Planck calculated H. Its constant. That's curious and extemely annoying. Dislike

[@PhysicsHigh]

It’s high school physics. He did so mathematically but it’s beyond the scope of the average high schooler

[@Felhek]

@@PhysicsHigh Someone should do it. There,s no video showing it. Must be truly interesting to see how H is calculated.

[@plamenpenchev262]

Very nice channel. But I have two remarks. First, Plank fitted the experimental data with his formula and then tried to explain it with thermodynamics and the necessary E = hf. Second: why everybody starts with Plank? 30 - 40 years ago spectroscopists supposed that the energy levels are discrete -- spectra are discrete. Also, the term black body is very confusing for a layman. BB is in thermodynamics equilibrium: it emits the same amount of energy that absorbs. Practically BB is not a black thing. As an IR spectroscopist (chemist, not physicist) I always wondered if the colour of BB is black as it is usually illustrated (by you too).

[@sarahc.167]

Thank you so much for this. So grateful to all the teachers who give their time to make amazing videos like this

[@clarrrisaj8520]

I spent so long trying to understand this topic but this video is so well explained. Thank you !!

[@seisukeota273]

I watched the video and enjoyed it.

[@zitscx886]

14:10 There should no pie in the numerator. Just pointing it out!

[@douglasstrother6584]

"Planck’s Route to the Black Body Radiation Formula and Quantization" by Michael Fowler details Planck's thermodynamic analysis of the entropy of Blackbody Radiation, which motivated his hypothesis to satisfy Wien's Law at high frequencies. Planck's application of Boltzmann's Statistical Mechanics led to his conclusion that the material of the walls emit and absorb radiation in discrete quanta. It's a great read.

[@Anonymous-by5jp]

Thanks. I’ll look it up

[@Anonymous-by5jp]

You’ve done a great job of shedding light on a complicated subject. Thanks 😊

[@douglasstrother6584]

@@Anonymous-by5jp You bet! It's very accessible, written at the Junior/Senior Undergraduate level.

[@hariharansankaran9012]

Thank you

[@douglasstrother6584]

@@hariharansankaran9012 "Theoretical Concepts in Physics: An Alternative View of Theoretical Reasoning in Physics" by Malcolm S. Longair contains a more details.

[@aretib1026]

first year studying physics at uni, really helpfull video!

[@PhysicsHigh]

Glad it was helpful

[@bipolatelly9806]

yes... we are electrical in nature.... (like EVERYTHING)

[@Buddha-Einstein]

Purely INTUITIVELY SPEAKING, HOW DOES QUANTIZATION show intensity going down at higher frequencies? Put the math aside, what stops energy from taking next quanta of hf?

[@climatebell]

I just found this video and liked it very much for its crisp educational explanation and added it to my Some Relevant Science Videos playlist so others will find it. Planck's equation is the key equation I used to create the GHG Lab calculator which performs precise and accurate computations for how much the Earth's System is heated from a change in GHGs. This is novel work to help head-off future needless mitigation activities. The link is on my channel if you are curious.

[@carlosalexandreFAT]

The association of the main numbers in mathematics reflect numerical sequences that correspond to the dimensions of the Earth, the Moon, and the Sun, in the unit of measurement in meters, which is 1" (second) / 299,792,458 m/s (speed of light in a vacuum). Planck's constant. Planck’s constant: 6.63 × 10-34 m2 kg. Circumference of the Moon: 10,916. Gold equation: 1,618 ɸ (((6.63 ^ (10,916 x 10^-4 )) x 1.618 x (10^3)= 12,756.82 Earth’s equatorial diameter: 12,756 km. Planck's temperature: 1.41679 x 10^32 Kelvin. Newton’s law of gravitation: G = 6.67 x 10^-11 N.m^2/kg^2. Speed of Sound: 340.29 m/s (1.41679 ^ 6.67) x 340.29 - 1 = 3,474.81 Moon's diameter:: 3,474 km. Frequencies of the Planets of the Solar System: • Mercury: 141.27 Hz; • Venus: 221.23 Hz; • Earth: 7.83 Hz; • Mars: 144.72 Hz; • Jupiter: 183.58 Hz; • Saturn: 147.85 Hz; • Uranus: 432 Hz; • Neptune: 211.44 Hz; • Planck constant: 6.63 × 10^-34 m2 kg. • ((141,27 + 221,23 + 7,83 + 144,72 +183,58 + 147,85 + 432 + 211,44) ^ 6,63) x (10^-17) = 10.916,17 Moon's circumference: 10,916 km. Orion: The Connection between Heaven and Earth eBook Kindle

[@MohammadAlshahrani]

Not that clear

[@tishamcmeekin9182]

I heard that Einstein filled the hole of understanding the formula. Can atoms be seen? How are they measured? I like Buckminster Fullers General Systems Theory model, wherein the metaphysical must be considered. Physics cannot explain metaphysics because by its nature it is finite or limited. All good for material universe, but what about that which we don't see physically? Even the full spectrum of color (as well as phenomena)... Thank you for sharing your insights.

[@wardelllindsay8677]

Planck"s Constants h=WL Copyright 2021 Wardell Lindsay h=2WbC/3XP=2WbC/3E33 h=Wb/2E15 4C/3E18=WL

[@chriselvidge6891]

Instead of referring to the wavelengths involved in the UV "catastrophe" as "smaller" wavelengths - I recommend using "shorter" wavelengths.

[@neillibertine3044]

There is fraud in Planck's law. The average energy of cavity is constant, while they treated it as variable. The term in exponential hf, here f is constant, fundamental frequency. So average energy term is constant, then it as lame as Rayleigh-Jeans model which have average energy as constant, kT. There are other laguna where they multiply f in average energy term as constant as variable. Though this doesn't effect on shape but size, intensity increases. Also approach in quantum is more classical than classical, because here energy of particles is constant, in fermi-dirac and bose-einstein, while maxwell-boltzmann has different energy.

[@davidwilkie9551]

Black-body e-Pi anti node singularity vanishing-into-no-thing zero-infinity axial-tangential sync-duration orthogonality. Inside-outside holographic time-timing positioning by i-reflection containment.

[@kaihanstein52]

Sorry... but so many things dont seem to relate to each other. Like what kind of physics did not explain the measurements? Based on what physics "did the curve go up"? How does quantinisation lead to a comletly different curve?? How comes that Planks equation led to just point - not a curve? (And so on)

[@samanthapaul650]

i didnt think Id be one of those people but this was posted on birthday lolol

[@vinosburhan2519]

Thannnk yoouuuuuu 🌸

[@boxfox2945]

How does this relate with radiated particle. Something radiated is slightly warm. But doesn't emediatelly show burns. Till later. & doesn't glow.

[@gregorykarimian3813]

This really doesn’t explain why there is no emission of uv radiation. This just says that energy flow is quantized. Before plank people thought the more energy an atom absorbed the higher energy radiation it emitted. In other words continuous energy transfer. This couldn’t be true because then incandescent light bulb would emit x rays and cause cancer. Obviously this is not the case. Instead he purposed that energy transfer was quantized and not continuous. Just like that staircase analogy he gave or a running faucet calmed to a drip. But this doesn’t explain why there is no emission of ultraviolet, or x rays. There’s two parts to this catastrophe. Quantization of energy transfer is the first part. The second is production of ultraviolet, and X-rays. In order to make these electromagnetic waves you need to excite the electron even higher. Turns out the energy provided by the current for an incandescent bulb does not have the quantized amount of energy that can make this excitation possible. However, x ray machines do, and that is exactly how they work. A quantum amount of energy is used to excite the electron and when it comes back it releases and x ray which produces contrast.

[@Hold_the_Front_777]

What if we want to understand the formula? Doesn't it kind of seem like an ad-hoc explanation to try to explain why our perception of physics didn't meet experimental observable predictions, so we basically had to reify the atom, and invoke quanta packets of energy to math it out.

[@fractalnomics]

The best example of a blackbody is snow. True. Go figure that?

[@philoso377]

Nice video and presentation. Ty and Jean gave us a curve fitting solution is mathematics but science. On the other hand Planck offer a final curve fitting solution is also mathematics but science. The catastrophe came out of our ignorance, selective learning and inability of connecting dots so to speak. Essentially, at the time the instrument’s sensor was sealed inside a glass container and we all know that glass attenuates infrared and ultraviolet that masked off real response, in the end we saw a distorted view on page 8:30+. That means we still don’t know the real characteristics is until we have found a new material but glass to preserve the real information in the signal, light. We have PhD everywhere today but they offer us D and not Ph. Without philosophy science is soulless.

[@philoso377]

Mathematician seldom study physics in depth. Theoretical physicist seldom run experiment themselves. Their theories were constructed on experimental reports and subsequently drawn by the academia and published by authoritative journals. The worst part in theorist is their lack of knowledge in the principle and operation in the associate test equipment and apparatus, as a result often over assumptions with false positive that trickle down into what the journal is selling. Each one knows a bit about but the whole. Known as specialization in modern times. The famous curve in page 4:48 could have been an unfavorable response in the test apparatus itself but nature that may never received any scrutiny (quality control?) We get so used to embracing infamous brand named products and theories has become a product but a study and debate of Nature and Science.

[@sheizm888]

Wow, I’m actually learning and fascinated this time around. Thank you

[@PhysicsHigh]

Glad you liked it.

[@mathman2170]

Early on (about 2:40), "smaller frequencies" comment should have been "smaller wavelengths -- no?

[@anzatzi]

It is not clear why introducing a quantized constant solves the 'catastrophe'. Thats the video I want to see! Thank you.

[@PrinceKumar-wx1sk]

awesome... sir, thank you :)

[@anthonyyee7481]

The incandescent light bulb is a Blackbody...how about the fluorescent light bulb is it also a Blackbidy ..if not then what is the reason? Tq !

[@PhysicsHigh]

Fluorescent light is not a black body. The light is a result of electrons jumping energy levels (quantum effect) Whereas black body radiation is different.

[@sauroman1]

Why curve goes down as waves get longer? Max Planck photo really looks like Jesse Pinkman :D

[@Xerneas23]

Drink some water then say your things. Ok??

[@isaiahmills714]

wow cool these videos are amazing

[@kugaththeplaguefather6332]

4:05 may i ask why does it go down? the red thing like raises up from the start but then goes back down

[@aaronweatherson4379]

...yep - sometimes recognizing reality is an act of desperation...

[@chrisraccoon1726]

great and precise explanation! very greatful

[@nathsegar9985]

This guy's smacking his mouth too much. Super annoying

[@sauroman1]

Where to find that spectrum calculator?

[@Banana-qg1jp]

This suddenly makes so much more sense!! Thank you soooooo soooo soooo much!!!!!

[@PhysicsHigh]

you are welcome - please share with your friends

[@nagahumanbeingzooofparticl8836]

very well explained.. thank you.

[@maazishaq7848]

Sorry but can anyone explain 2me simply How quantuzing the energy solved the problem of the curve ?

[@PhysicsHigh]

I plan to do a follow up video on this question.

[@vispi1944]

Very good and clear presentation.

[@saifrahaman8974]

Thanks sir

[@saveearth9816]

Thank you very much.... I watched many videos to understand... (why we say U. V catastrophe) I thought that because of harmful EM radiotion (ionizing radiation) from U. V & and shorter frequencies.... BUT NOW I REALIZED BECAUSE IT BREAKS THE EXPECTATION OF THE CLASSICAL PHYSICS

[@shaden8322]

How did planck tho explain it using one law?

[@savannahparrish7261]

I needed this thank you 🙏!

[@sebastiendubois8326]

why the curve come down at ultraviolet ??

[@dnstone1127]

(James) Jeans is pronounced like the denim trousers not like French Jean

[@PhysicsHigh]

You are right. no longer do that.

[@Kage1128]

Sorry but still don't understand why the curve decreases with higher frequency or lower wavelenghts

[@PhysicsHigh]

They key to this is understanding what Planck assumed. 1. He assumed that energy was quantised and that every bit (emitter)of the substance emitted a discrete amount BUT the formula he discusses makes a prediction or probability that an emitter releases its energy. And the higher the energy , if quantised, the less likely it would emit that energy. 2. He assumed that the energy was related to its frequency (E = hf) So put that together... The higher energy, the higher the frequency, but it's less likely to have higher energies packets being emitted so therefore less likely frequencies in the UV range to be emitted. Notice - " less likely", not zero, which is why we still have some UV emitted.

[@gyattrizzV]

Damn who is learning this in highschool

[@isaiahmills714]

if our sun had ten times the amount of mass that it has now it would be brighter more massive and hotter and more blue do you agree?

[@PhysicsHigh]

+Isaiah Mills that is correct

[@TheMaverickSoldier]

Knowledge Is Power Nonsense ... the mightiest Sumo is always the largest. That is why the eat so much. The bigger the hurricane, the more intense the storm. Unless your like my girlfriend and believe that, "it's not the size of the iceberg but rather the motion of the ocean". That's usually how she cheers me up.

[@bipolatelly9806]

Isaiah Mills The Sun is NOT a nuclear reactor... so NO! The Universe is electric!

[@bipolatelly9806]

High School Physics Explained pffft.... that will get her a tick in "high skool fisics", but you are completely wrong! The correct answer is "you are sadly mistaken... and I blame myself and others like me". Then you should be recommending she goes to the Thunderbolts Project channel for REAL science... The Universe is electric.

[@bipolatelly9806]

Rick Aredetfredhi Xavi i gave you a tick for your clever joke.... Alas, I feel you are stuck in the fantasy Newtonian-einsteinian multiverse... The Universe is electrical in nature.... Thunderbolts Project for REAL science.

[@abdelrahmanabdelraouf6201]

Thank you truly for the great video. Taking a modern physics course this semester and the TA explained it poorly, appreciate the help!

[@debbiehariette6335]

Thank you :0)

[@charlieangkor8649]

You don't need quantum mechanics to fix the ultraviolet catastrophe, just don't use a model which is obviously against common sense. The positive and negative electrical fields around electrons and nuclei are soft and springy, therefore the collisions don't produce high frequencies. I other words, colliding pillows don't produce a lot of treble sounds.

[@moogzoliver]

Reminds me of homeostasis

[@tiagoromero1777]

How did he came up with that? I think he figured out that energy was quantized and to get the value he just tried smaller and smaller numbers until the equation matched up with the experimental data... Then just multiplies that constant by the frequency and there it is, such a simple but beautfil approach to solve the problem

[@mariaorsic9763]

Please stop slurping your saliva and smacking you slips. It destroys your content.

[@PhysicsHigh]

Yeh. Old video. I’m better now

[@JaykeSapalaran-iq3qs]

Great video information 👍❤thank you for sharing your knowledge and experience 🇵🇭🫡

[@joshuazeidner8419]

heat is not equivalent to infra red

[@vinitachaudhary472]

Can coal be an example of black body?

[@amanbhanse5645]

great video!!.....this video helps me to understand the planck's law.....other videos on youtube are just waste of time,,,,,,....

[@sosscs]

What kind of function is that graph? it's so weird I cannot understand it. How come there's 2 points in the y axis? usually, when you pick a value from the x axis it give only one value from the y axis, but how come the y axis is giving 2 values?

[@philaofishx4876]

Is this what the Pink Floyd Dark Side of the Moon cover was trying to explain? Are we all just "bricks in the wall'?

[@a.tigerjr.6132]

So are we saying that the Planck constant was utilized because we simply don't have a perfect radiator to experiment with to prove the classic model?

[@huntergirl7275]

I think the white line you drew on the ultraviolet catastrophe screen should show exponential growth, not exponential decay, though...

[@goddess_ofchaos]

Me: searches the whole internet for an explanation about the formula Planck came up with Video: this is Planck's formula Me: FINALLY Video: but you don't have to understand it, it's not important!

[@PhysicsHigh]

Sorry. Made for high school physics and the formula is beyond that scope. Plan to do an addendum to elaborate

[@shenzshorts3352]

@@PhysicsHigh Sir plz could you explain the graph i can’t get it...9:11 why their prediction was wrong,why the graph is curved and not a straight line with increasing intensity and decreasing wavelength...why the intensity suddenly falls down....? I’ll be very thankful...

[@goddess_ofchaos]

@@PhysicsHigh ah that's no problem I truly appreciate your work here! It would be nice if you have the time to explain the formula, I'll look forward to it. But of course the essential information is already in the video. Keep going!!

[@urwahsohail1813]

Oh my god. I have watched a lot of videos, and This is just incredible.

[@jzylkin]

I did not find this helpful

[@visasaarinen6051]

I must be stupid but I still don't understand the concept of quantization. If the Energy obeys the equations E=hf sure there is a Planck's Constant there but if one graphs energy as a function of frequency E(f) it's a smooth curve, a line with a slope of Planck's Constant to be exact. So how come people talk about stairs and steps? If the frequency distribution is continuous so is the energy distribution. What am I missing? a confused teacher asking for help.

[@PhysicsHigh]

You’re not stupid. Great question. Haven’t time now but will respond in the next few days.

[@PhysicsHigh]

We ned to clarify what quantisation means and what it doesn't mean. You are correct, the graph you state is smooth since it displays the energy of photoelectrons for a range of frequencies. So yes, that energy graph is continuous. But thats not what the quantisation is about. What Planck determined, that for any given frequency , the energy of a quanta of EMR is a whole number multiple of the frequency by Planck's constant. ie E = nhf. So the smallest amount of energy will be where n = 1 so E = hf. It was Einstein who was able to explain the PE effect by saying that only photoelectron can be released by one photon whose energy is E =hf. so if you get get a RANGE of frequencies then you will get a RANGE of energy Now this would suggest a continuous range of energies. But we now know that emission of EMR is a result of quantum effects ie electron transitions between energy levels, which results in very specific frequency emissions and thus discrete energy emissions Does that clarify?

[@tietovisa585]

@@PhysicsHigh Thank you for your explanation! I know it's been two months since you answered my question but back then I wasn't able to put into words my follow-up question. I hope I can do it now. Your explanation clarified most of the things I was unsure about but there is still one thing I need to ensure. When it comes to a black body radiation the radiation is temperature dependent. And that's why I made a conclusion the radiation is due to the thermal motion (vibration) of the atoms (because atoms consist of positive protons and negative electrons that emits EMF when in acceleration). But that radiation wouldn't be quantized because the atoms themselves could have arbitrary vibration speed/acceleration? So the previous conclusion must be wrong. Does it mean that even though the black body radiation happens due to the temperature of the object it's not because of the atoms vibrating in the substance itself and those vibrations cause the emission of EMF but because vibration energy results electron transitions between energy levels and those transitions are quantized and because EMF is a result of those transitions that's why the EMF radiation is quantized as well? I hope this wasn't too confusing. Thank you in advance!

[@PrinceKumar-wx1sk]

but I'd have loved if u would have explained the derivation of the formula Planck used to predic nature of the wave

[@akshinbarathi8914]

sir is it like the number of photons become constant after the max inetsity like in photoelectric effect?

[@akaBaye]

but why does classical physics fail to explain this? like WHY explain it to me wheres the contradiction

[@addosatria1871]

far as I know (correct me if I'm wrong), it contradicted against conservation of energy, soo because the blackbody continues to emit UV light with an infinite Intensity which means free energy and broke the classical physics theory of 1st law thermodynamic that state "Energy cannot be created or destroyed it just change form".I think, sorry if I'm wrong I still learning about the fundamentals of quantum in physics.

[@akaBaye]

Addo Satria appariciate the reply my man, yes I heard this somewhere as well I’m just wrapping my head around these concepts as well. Thank you!

[@mohamadelchami9010]

Bravo!

[@n.1822]

thank you so much this is amazing

[@PhysicsHigh]

you are welcome - please share and spread the word

[@capitaopacoca8454]

Finally understood what a n body is. Thanks!

[@valsarff6525]

The physics broke down with Kirchhoff's Law. It was never experimentally proven, and is not valid. In fact if it was correct, we would not have cell phones or MRI scanners today. Max Planck never linked iit to the physical world. The stars are not black bodies. Astrophysics made it all up.

[@ralphhleihel5079]

Can you elaborate more?

[@theskyatnightrawunderthedome]

ugh~

[@7grhpsyfuck272]

dont join CRA

[@miraklTutorial]

You know what, I had been calling Eistein a thief who took Planck's work to call it photoelectric effect. Now when Planck himself says "an act of desperation" i don't understand this, when he got every thing to explain the quantum nature of light. You know what my problem is that i unable to differentiate between Planck's quanta and Einstein photon.

[@PhysicsHigh]

Planck tweaked their maths to fit the data and was basically making a mathematical statement about energy being quantised. He did not understand the significance of it initially. It was Einstein who did.

[@bipolatelly9806]

I "am aware" that the Universe is electrical in nature....

[@MichaelVLang]

This must have seemed very odd to Planck and others then...it is such a strange concept...I enjoyed your explanation, thank you!

[@wlo23ex81]

At 6:41, it says that black bodies absorb radiation right? This has been boggling on my mind for a bit now, but what about a lightbulb filament that doesn't necessarily have to absorb electromagnetic radiation, and is counted for as a black body. The thing is, that it also reflects light, so how can this be a black body?

[@PhysicsHigh]

A filament MODELS a black body. But it isn’t perfect. About the closest thing to a black body is a star. A true black body does not reflect any light.