Energy of a nuclear blast

Detailed calculation of how to determine the blast energy of an explosion from photographs. This is the second part of the presentation of the work of G.I. Taylor to model the first nuclear explosion using dimensional analysis.
G.I. Taylor's paper I royalsocietypublishing.org/do...
G.I. Taylor's paper II royalsocietypublishing.org/do...
J.E. Mack’s report dp.la/item/a13166728fbbfe61a7...
Trinity test code and data github.com/jsdiazpo/Saving-th...
Beirut explosion paper: arxiv.org/abs/2009.05674
Brightness of the Trinity Test • How bright was the Tri...
Series on Nuclear Weapons Physics • Physics of Nuclear Wea...
Credits:
Shot Dog, Operation Tumbler-Snapper footage, Los Alamos National Laboratory
Trinity test photographs and footage, Los Alamos National Laboratory
J.E. Mack Los Alamos badge photo, Los Alamos National Laboratory
J.E. Mack’s report, Digital Public Library of America
100-ton TNT test photographs, Los Alamos National Laboratory
WWII bomb designs, bomb drop announcement, Los Alamos National Laboratory
Truman’s speech footage, U.S. National Archives catalog.archives.gov/id/23630
Truman’s speech transcript, Harry Truman Library www.trumanlibrary.gov/library...
Beirut explosion photographs and footage, courtesy of Newsflare Ltd.

[@matthorn6118]

Excellent videos! On multiple levels: - Physics - Math - Research - People vindication - Yet another example of how much History is distorted through time. Makes you wonder on Narrative vs History, on non-physics topics.

[@jkzero]

Thanks, I am glad you liked the video. I am curious to know what brings viewers to the channel, were you searching for something in particular or did the 'mighty algorithm' find you?

[@matthorn6118]

@@jkzero Algorithm brought me here.

[@jkzero]

@@matthorn6118 Thanks for sharing and I am glad the algorithm is working, I hope you find the other videos of interest too and welcome to the channel

[@dbp_patel_1994]

Please keep making these excellent videos. Really appreciate you teaching us all this material.

[@jkzero]

I am glad to read that you enjoy the content. When I decided to leave the academic life a few years back, the one aspect that I knew I would miss the most was teaching; I was fortunate enough to teach at all levels, from high-school to undergrads all the way to master and PhD students. The many teaching awards that I got from my students reflected that my style was appreciated. I feel that creating this KZbin channel is giving me the opportunity to continue one of my favorite activities and also reaching a far greater audience. I will continue, I just ask for support by sharing, liking, subscribing and all those things that make the 'mighty algorithm' keep a KZbin channel alive.

[@deso425]

Excellent videos as always.

[@jkzero]

Glad you like them!

[@duaalok]

Another amazing piece of information. Looking forward to more!!

[@jkzero]

More to come! Stay tuned.

[@n6mz]

Incredible content, thank you. I could listen to your analyses all day.

[@jkzero]

Glad you enjoy it!

[@hypercomms2001]

Thank you Dr Diaz... impressive!

[@jkzero]

Glad you liked it!

[@steveinmidtown]

that initial footage is just insane.

[@jkzero]

this was an experiment to evaluate smaller implosion designs achieving higher plutonium compression plus testing deuterium boosting for smaller. Props to the cameraman for standing below a 19 kt blast

[@mikeoftheclandobson5483]

Yet another fantastic video!! 🙏😁

[@jkzero]

Thanks again!

[@dholgadom]

Excellent video Jorge!!!

[@jkzero]

Glad you liked it!

[@5eurosenelsuelo]

Great work!

[@juansalvemini9270]

Muy interesante. Se agradece ver los cálculos en detalle, no solo la historia y contexto. Haces contenido de mucha calidad… nos vemos en los 100k subscriptores!

[@jkzero]

gracias por el comentario y el pronóstico tan optimista, me encantaría llegar a más gente. Enseñar fue siempre una de mis pasiones y ahora siento que tengo la oportunidad de compartir mis temas de interés con una audiencia muy amplia.

[@CaptainCalculus]

It should be noted that the reason there are those lines in the sky behind nuclear blasts is to measure the yield of the blast.They are some distance (I don't know what distance--500 feet??) behind the blast. by analysing the film rolls you can see when the shockwave blurs out the lines you can calculate the yield using these formulae.

[@RealSigmarDelta]

Thank you Dr Diaz! Genuinely interesting. I learned something ❤

[@jkzero]

Glad to read that "I learned something," that made my day

[@SuperYTPmaster]

Another great video. Have you considered making a video on the K-T asteroid impact? I think a physical analysis of its immediate effects on Earth + the atmosphere would be super fascinating. I didn’t find out until recently that out of the 75% of life on earth that died as a result, it’s likely most died within the first 48 hours of impact. The immediate energy release was so powerful that it effectively cooked the atmosphere.

[@jkzero]

thanks for the suggestion, I agree that this would be very interesting; however, my concern is that I honestly think that this topic goes beyond my expertise. I would have to read a few papers about it.

[@cewkins721]

From my calculations and what i saw online the energy of the asteroid was something 10^23 J, shit load of energy, makes sense it messed everything up

[@jkzero]

@@cewkins721 such a number is just an insane amount of energy

[@bonetiredtoo]

There is always another possibility. Taylor was part of the British delegation to the Manhattan project working on the implosion design of the plutonium bomb and indeed he was at the Trinity test. I wouldn't be at all surprised if he had prior view of Mack's photographs but couldn't publish until they were declassified a couple or so years after.

[@jkzero]

I fully agree, G.I. Taylor was probably the most illustrious physicist of the British delegation to the Manhattan Project and I think that there is no way that he had not seen the photographs and even done the calculations on his second paper before Mack's report was declassified. Nonetheless, the public document that he wrote was submitted to the Royal Society in 1949, years after all photographs had been publicly available. Therefore, claims that he revealed secret information are just a nice narrative.

[@neti_neti_]

बहुत सुंदर प्रस्तुती। 👏👏👏

[@fightingforcatalonia]

Grande! Sigue así!

[@jkzero]

se agradece la visita, también la difusión

[@johnhamilton7762]

This is fascinating but forgive me for being dumb here but how does using a single equation and pictures of blast radius take into account energy from the heat, the light, the x-rays as well as the kinetics? Is it not an oversimplification?

[@jkzero]

what you are bringing here is far from a dumb question, it is in fact something I am discussing with experts all over the globe since some time now. Notice that I am very careful to refer to the calculated energy as "blast energy," this means that with Taylor's method you only get the energy that produces blast but not any "wasted energy" in the form of ionizing and thermal radiation. I hope to report in the future the details but trust me when I say: this is not a dumb question at all.

[@jasonl_]

@@jkzero Actually a very good question and I look forward Dr Diaz's explanation one day. I'm guessing that as the official total yield of the Trinity test is 22-23Kt, that extra 3 to 4Kt of yield is the non-blast yield (ionizing and thermal energy).

[@cewkins721]

Great video once again and a perfect part 2 to the previous one, the math is simple but the meaning and use is great, also i appreciate you publishing a paper on the Beirut explosion, i downloaded the file and it looks great, i still remember that day i was leaving a doctors appointment when i heard someone talking on the phone being confused and scared saying something about an explosion only to come back home and find out what happened on the news...truly terrible

[@jkzero]

I recall the day of the Beirut explosion too; I saw one video on Twitter and my reaction was "no way, this must be fake" but then I saw a couple more and by comparison it was clearly true. My next reaction was: "that Wilson cloud will make many believe that this was nuclear." I did some back-of-the-envelope calculations and got ~0.7 kt. I was tweeting so much that my tweets appeared in many newspapers and even CNN asked me to appear live to comment on the explosion. It was an interesting and scientifically active day but also a sad day. It was a terrible event.

[@cewkins721]

​@@jkzero Oh i see yeah, Btw i wanted to say that the analysis paper looks really good with the way the images are formatted and the text, i loved it!

[@jkzero]

@@cewkins721 thanks for checking the paper out. The format is standard LaTeX used for all scientific publications. You can just google it and find templates; on Overleaf you can find a collection of LaTeX templates under "Academic Journal"

[@cewkins721]

@@jkzero Ah thanks a lot for the information!

[@AntoniBancells2304Mates]

Thanks for your excellent videos. I've enjoyed with your explanation. I'm a high school teacher and this video has inspired a lesson for my classroom. I have taken some information from your video, and I've made a simpler explanation for "dummies". I've used only two photos and measured radius using GeoGebra. I have obtained 9.2 KT. I have checked the calculations, I have compared with yours, and I've realized that the results are very sensitive to the value of n. From two photos, the value that I've estimated is 6.78. Anyway, for pedagogical purposes, for me is enough. I've cited your video for further study into video description. Thank you very much! PS: How are made the graphics into your videos?

[@jkzero]

Wonderful! You have no idea the joy when teachers tell me that they are using my videos, this has happened already with many others. Thanks for sharing this and thanks in the name of your students for going the extra mile finding interesting problems. Yes, the solution is very sensitive to the value of n because the energy depends exponentially on n. This is why the less pictures are used, the noisier the result. I insist in the video that many articles say that Taylor only use a few photographs but that is incorrect: he used 25 precisely because he knew that that the more data the better. All my lots are made using a Python library called Matplotlib and the animations are made using Manim, an open-source library on Python created by 3b1b docs.manim.community/en/stable/examples.html

[@tamassoos5915]

Excellent video. I'd have loved to see some error analysis to understand how well the formula works and how significant was the discrepancy between the estimate based on the images and the official value. It's hard to tell if the 4.5% or so relative error is relevant or not.

[@jkzero]

Uncertainty quantification is very important and here you can see that Taylor was a theorist, he included no uncertainties. I guess it is easy to redo his analysis, the photographs are publicly available.

[@shotloud6838]

Is it possible for you to got into a little more detail on how he got the n intercept of 6.94 please.

[@jkzero]

Taylor did a simple linear regression of the data, from which he determined the slope "m" and the intercept "n." You can take the data and even do this linear regression in Excel. I wrote a paper explaining this in detail, you can find it here: arxiv.org/abs/2009.05674 If you have any questions just let me know.

[@JP-re3bc]

I only wish I'd have had such a Physics teacher in college.

[@jkzero]

thanks fro that compliment, I was lucky enough to have the opportunity to teach undergrads, master, and PhD students; I really miss teaching, that is one of the reasons I launched this channel

[@chalkchalkson5639]

7:11 No errorbars or units on the plot? Didn't you meme about that being a mortal sin in physics in the seminar version of this? ;)

[@jkzero]

thanks for noticing and remembering my comment on this topic: yes, I firmly believe that data without error bars should be always questioned. In this case, I simply reproduced the plot that Taylor presented in his paper, which has no error bars. Using the words of the great Wolfgang Pauli: "this is something no theorist should ever do."