Electromagnetic Waves - with Sir Lawrence Bragg
Experiments and demonstrations on the nature of electromagnetic waves.
The nature of electromagnetic waves is demonstrated first with the aid of models and then by a reconstruction of Faraday's experiment on induction. The range of electromagnetic waves is next illustrated, followed by a series of experiments using a klystron. The measurement of wavelengths is introduced by showing standing waves with the Vinycomb model, Sir Lawrence then illustrating the same principles by applying electromagnetic waves to Young's pinhole experiment.
From the original programme notes: Sir Lawrence Bragg at the Royal Institution of Great Britain Since 1826 a series of lectures, planned for young people, has been given at the Royal Institution during the fortnight after Christmas. These lectures, 'adapted to a juvenile auditory' to use the nineteenth-century phase, were started as a new venture in science teaching. It is the tradition to illustrate the CHRISTMAS LECTURES with numerous experiments which are on an impressive scale and as far as possible of a novel type. Many experiments first shown in the Royal Institution theatre have become classical bench-experiments in schools and colleges, and many of the best popular scientific books have been based on CHRISTMAS LECTURES. A scheme was launched in 1955 to give corresponding lectures throughout the school year, because it seemed very desirable to use the facilities and traditions of the Institution to the full and thus make it possible for a larger audience to participate. The idea was proposed in the first place to a few science teachers in schools, and with their help it was started in a small way. The lectures had an enthusiastic reception, and the scheme soon grew to its present proportions – over twenty thousand young people now come to the lectures each year. The main idea behind them is to show experiments, illustrating the basic principles of science, which are on too large a scale or involve too complicated apparatus to be readily staged with school resources. The majority of the lectures are on physical subjects, but chemistry and biology are also represented. In 1965, Lord Bowden, who was then Minister of State in the Department of Education and Science, expressed a wish that the lectures given by Sir Laurence Bragg be recorded in the form of films, and arranged that a sum of money be earmarked for that purpose. The series Sir Lawrence Bragg at the Royal Institution is the result of his interest. The films have been commissioned by the Educational Foundation for Visual Aids and shot on the premises of the Royal Institution. At first an attempt was made to film the actual schools' lectures, but there were a number of drawbacks to this procedure. Ideal positions for the cameras were not possible in a crowded lecture room. An hour's talk is too long, the film had to be divided into three or four sections, and it was not easy to tailor beginning and ends to the sections. It was finally realised that it would be much better to shoot each film as a separate project, with no audience and complete freedom for the camera team to take the long shots and close-ups in the best way. The possibility of close-up shots is a great advantage, because it enables effects to be shown which it would be impossible to demonstrate in a large lecture room. The present series consists of sixteen films covering the schools' lectures dealing with magnetism, the properties of matter, and vibrations and waves. It is hoped to include electricity and other subjects in a further series. In the main, the experiments are those actually shown in the schools' lectures, modified for filming where desirable. The action before the camera is in each case carefully rehearsed so that the performance of the experiment is seen as clearly as possible. No attempt however has been made to prepare a 'script'. The talk is quite informal, not a prepared one, in the belief that it will be fresher and more interesting if given in this way. It is hoped that the imperfections, inevitable in an impromptu talk, will be overlooked for the sake of its more personal nature.
Crown copyright information is reproduced with the permission of the Controller of HMSO and the Queen’s Printer for Scotland.
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People who were alive during the invention of this technology really teach it better than people nowadays. Nowadays, people just assume you know things and skip past all the fundamentals, but back in the day, they had just learned of this technology and they taught it to newbies the way they learned it.
I guess em-Waves werde discovered 100 - 150 years earlier..
I did not expect the glass lens to affect the EM waves like that! That really makes a connection for me that was always missing. The idea that radio, light, and X-rays are the same "stuff" but at different frequencies is now clear in a way it never had been before. My mind is blown.
a couple of year ago in some campus dorms in east europe which didn't have internet cable in every dorm but only a wireless point at every floor people would put their wireless receivers near some windows in the hope of getting a better signal. curious now if a decent size glass jar with the opening towards a wireless emitter in which you'd have a wireless receiver would amplify the signal
Here's some more for you. Modern science isn't correct..... All energy and matter in one simple explanation.... here goes... First we have a radio wave all the way to gamma waves which in turn create hydrogen then from there everything is basically a compound of hydrogen and will decay back to hydrogen before turning back to gamma waves..... There are no free moving electrons within matter.... I use this analogy to simplify it in my mind..... imagine a line of people standing a mile long (each person represents a copper atom in a wire) the first person starts a Mexican wave at one end ( the source ) , as the information propagates along the line ( by exciting each atoms magnetic field ) you would see an continuous wave of the peoples arms transferring the charge/information back and forth but the atoms and electrons don't actually move at all..... Think about it, from the source where electricity is "generated" to the ultimate end use, there's various breaks in chain of that electricity, it goes through controllers, transformers, all sort of components.... the transmission happens because of the magnetic field strength of the atoms in the wire being increased and decreased, not because of an actual "electron" flowing anywhere....
@@WSmith_1984 I like it!
Yes that was very interesting and informative! I was also surprised by that, I wish these types of experiments and demonstration were still done, I think it would help in the understanding or it would have helped me at least.
Indeed I have the same problem, he uses a PERSPEX lens, how can it focus EM waves? Something is wrong.
This is a fine demonstration why fundamentals need to taught by great masters and not grad students. A marvelous opportunity to learn !
There are some pretty good grad students tho, when they aren't swamped with their own work
Great learning can be found in many places and it is good advice to grab it with both hands, be critical in your thinking and question everything. Don't be taken in by a pipe, a tweed jacket or some grainy footage, at least, not for sentimental reasons. That's not what we are here for. The laws of electromagnetism have not changed and there are many modern teachers that will take you down the rabbithole of EM theory, just as well as Sir Lawrence did here, ..if maybe a little less dapper in presentation :)
@@johnc3403 here's some for you. Modern science isn't correct. All energy and matter in one simple explanation.... here goes. First we have a radio wave all the way to gamma waves which in turn create hydrogen then from there everything is basically a compound of hydrogen and will decay back to hydrogen before turning back to gamma waves..... There are no free moving electrons within matter.... I use this analogy to simplify it in my mind..... imagine a line of people standing a mile long (each person represents a copper atom in a wire) the first person starts a Mexican wave at one end ( the source ) , as the information propagates along the line ( by exciting each atoms magnetic field ) you would see an continuous wave of the peoples arms transferring the charge/information back and forth but the atoms and electrons don't actually move at all..... Think about it, from the source where electricity is "generated" to the ultimate end use, there's various breaks in chain of that electricity, it goes through controllers, transformers, all sort of components.... the transmission happens because of the magnetic field strength of the atoms in the wire being increased and decreased, not because of an actual "electron" flowing anywhere....
@@johnc3403 indeed, for some reason people always seem to forget there's a happy medium between great master and grad student called a teacher
Actually seeing the experimental apparatus used to investigate these phenomena is truly eye opening.
Super..much better than modern animations
Sir Bragg is a legend.
It is much easyer to animate than make things in real. Beside, you have full control during creating animation.
Nonsense.
Why isn't science being explained this elegantly anymore nowadays?
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I'd argue that it is! There are some really really great lectures all over the world. Additionally, we have resources like youtube, and books like Griffiths Introduction to Electrodynamics for free as a pdf on the internet. If people have a bit of calculus and diff eq background (if not khan academy is great) the world is their oyster! You can pretty much learn whatever you want
im quite familiar with most of the resources you’ve mentioned. They are very good, but nothing that comes close to this here, as far as physics teaching goes..
Because nowadays, everything is done in a really half-assed don't-give-a-shit manner, including explaining science.
Because people scream about it being 'White supremacy'
When you hear a man speaking in that old fashioned more upper class English accent, you listen! I learned so much, and this is how physics should be taught, thanks for posting.
That visualization of a wave with moving parts is amazing
I'm fortunate to have viewed this presentation.
I wish to goodness high school and colleges taught concepts like this before beginning the math
The math is what gives you proper respect for the physics, and also shows you even more on how beautiful the phenomenon you are observing is.
It's like he said. 02:49 what he is teaching it's just 'the nature of this'
I agree showing concrete before the abstract is very important. Show visually first and then the math to explain it. Then, the Math becomes much more interesting.
It's interesting that he pointed out it was Faraday that made the discovery, who could not do the math. Maxwell who could do advanced math was able to refine Faraday's work into exact math equations. Quantum super semetry is basically described as best guess for X1 and X2 and 3and4. In particular physics they use the P word to signify best guess on what you know. When they hunted the Higgs particle they thought it should appear within an estimated energy range. There again best guess. You can sum it up as the field of discovery isn't going to be the work of elegant equations, but after the discovery then the math can make the discovery universally understandable, and defined. In Physics Fineman had all kinds of squiggly lines and arrows he used instead of math, because they represented what he thought, but couldn't prove.
bzzzt, wrong.
Quite brilliant demonstrations! Thanks for posting!
It's butefull lesson. Благодарю тех кто выложил. Такие лекции заставляют задумываться над многими процессами .
Что за излучатель в его опытах не подскажешь?
What Sir Lawrence Bragg demonstrating is well understood: He demonstrated the deference between Education and Learning. Hats off to him in respect.
Thank you Sir for such a great lecture and your contribution in science education.
Thank you, an incredible illustration of electromagnetism and wave propagation. The video is a gem.
You changed my way of thinking about EM waves...really better than modern explanations with animation
I have to say that this is the most simple and exciting lecture I've ever taken in my entire life. I just really hope that physics is taught in this way all around the world to make new scientists.....
He is my favorite scientist since i was 10 years old now i am almost 18 it has been 8 years aprox and i been loving physics since...physics is my first love...
The earth os flat covered by molten glass dome saline sea moving around magnetic mountain at north generates charge which is conducted through this firmament simultaneously powering stars and running sun positive hot and moon negative cold lights around mixing air into noble gas filled upper atmosphere now you know what tesla knew and you can understand our fathers creation
thats cool........wb
Wow ... a wonderful find ... of real quality ... both this video and your many archives. Thank you.
Great public demonstrations!
The way this is filmed is incredibly therapeutic lol
How beautifully demonstrated. Good old days
Great Video many thanks
Finally feels confident of what i thought i knew.
This video should formally become a part of school curriculum
Fantastic presentation on EM energy and waves. Thanks.
Good demonstration about electromagnetic waves. Thanks for the video.
Interesting to see demonstrations! Thank you.
TWO great science educators at work; Lawrence Bragg AND Bill Coates, long-term senior demonstrator at the Royal Institution. I am glad to have had the privilege to meet the latter, a personal hero.
Genial! Una de las explicaciones más claras de las bases del electromagnetismo que he visto. Realmente excelente!
Many thanks for sharing this pearl of wisdom
The best physics lesson I ever had. Thank you.
Old school physics, I love it. In college I used Debye Scherer & Guinier cameras and developed the x-ray film in a darkroom, and measured the spacings between the rings with a ruler to get interatomic distances. In grad school one of my jobs was to automate an 1960s era diffractometer with a DEC PDP-11 computer, putting stepper motors on it. Before that, there were ordinary motors and the diffraction pattern came out on a chart recorder that was also analog. This seemed like the cutting edge of science at the time, lol.
Amazing!! With zero mathematics, a rare gem video making us watch the actual behaviour of invisible. Grear professor.
The perfect teacher. Thank you.
This is awesome. Explanation made simple.
Thanks a lot for sharing these videos !
great video, great examples, thank you to him and you
Very informative and easy to grasp. This British gentleman is a good teacher indeed.
He was Australian. He was also the youngest person ever to get the Nobel Prize in physics or chemistry.
@@ianl707 This ageism is annoying and *not* a good indicator if someone is smart, a good teacher or not.
Btw... this Klystron was rocking a solid 30GHz ! Stunning to think about that this has been allready done in the 50's.
I KNOW ABOUT EM WAVES EVERSINCE I WAS VERY YOUNG WHEN I USED TO STUDY RADIO AND TV. BUT THIS CLASS DEMONSTRATES THOSE PRINCIPLES SO WELL THAT NOTHING'S LEFT FOR IMAGINATION. YOU ACTUALLY SEE WHAT HAPPENS. WHAT A MASTERPIECE OF PADAGOGY. SCIENCE FLOWS LIKE A RIVER WITH THIS EXPLANATION. GOD BLESS SIR LAWRENCE.
Excellent. Really enjoyed this one. Thanks.
Outstanding! Wish I'd seen these demonstrations in 1968!
I wonder if any of the people from 1968 wished they could see these demonstrations in 2021. 😁 I know what you meant though. It would have been amazing to attend one of Sir Lawrence Bragg's presentations.
Was it 1968? I was wondering. If so, how did you find out?
This really is amazing. It visualises something invisible and helps understanding electromagnetic waves. Thanks a lot.
Incredible teacher. Such a clear demonstration, beautiful apparatuses. mechanical heaven for me. tnx.
true knowledge is pristine and clear
it's amazing explains .. thank you Ri Archives
Interesting demonstrations, thank the physics gods someone had the forethought to record it! The intro leads me to hope there might be one or two more topics covered. ❤
A very good demonstration of what light really is. A blazing magnetic wave!
Outstanding. Thank you.
Very good lecture ! befor , I watching this video I don't know what is EMR after I know about what is EMR . Thank you sir
Marvelous presentation
One of the most amazing things on this video is the use of a Glass lens to capture and focus a radio wave into the antenna. That was amazing ! I seen it and said No Way!😮 But simple physics works !🤔 I will have to try this! I want to build a super antenna. I heard that using Mercury in a tube connected to your antenna it works great.
When measuring the Wavelength, the professor clearly said that based on the lengths measured, the waves were short in length and were similar to light waves not radio which have longer wave lengths. Or perhaps he changed the wave generating apparatus after using the lens and before measuring the wavelengths..
This is too much for just one video 🎉🎉🎉thank you so much best science video ever watched on KZhead by me
Glad to have found this wealth of information
superb demonstration and experiments
This was a really interesting and great video. He was able to explain things very well, kept me interested in what was going to happen
Excellent DEMONstration.
Maybe not the most charismatic gentleman but I do love all the demos! Helps the simple mind (like my own) grasp these abstract phenomena.
this is so wonderful, thank you so much!
This is a fine demonstration why fundamentals need to taught by great masters and not grad students.
It's really amazing to hear it from the man himself. A bit like the Feynman lectures on Quantum Electrodynamics.
Great video! Answered several of my questions.
Magical! Thank you !!!
This was amazing learning Thank you ❣️
Wow grabe! I learned a lot thanks to this channel...
Really a privilege to learn from a Nobel Prize.... And yes, he´s the one (with his father) of the Bragg´s Law !
this video series is a great series on experimental basis for chemistry
50 Hz ?? ( @ 4:56 ) NOW the British accent MAKES PERFECT SENSE This is ABOVE and BEYOND anything, and everything I have viewed on KZhead thus far
this is extraordinary ❤️❤️❤️
Bravo! Well done, old boy!
Just wonderful.
Mind blowing proff👍🔥🙏 brilliant
Omg the focus lens blow my mind
i wish schools where like that in my age now. Amazing Video sir
Very informative and also interesting video
real knowledge is pleasurable to receive
This knowledge is actually just a description of all the stuff people should know. It's like going to a restaurant, and the waiter is spoon feeding you.
It's very important video...
Thank you, Ri.
Thank you!
Amazing ! ! ! 👏 👏 I love Electromagnetism Science.
Incredible professor
Great document of science history. Love the giant wax prism 10:15 😁
Got to hand it to the Royal Institution Of Great Britain, they make some very informative videos!
What a wonderful career. Helping others "to understand"... 500 good human points awarded - posthumously I wish I was better at math & engineering. I wasn't so I had to settle for working at Boeing
In my school age if I could have this kind of teacher I could have become a great scientist
Very nice lecture!!!
Amazing!!
Love this video.. These days we need more experimental videos likes this ... not sure why this got 40 dislikes?
How do you know it got 40 dislikes?
@@Number6_ Dislikes were still visible years ago.
In fact all of these good videos should become part of a course in colleges
Super vidéo scientifique ☺😊😀
It's very good teachings
Brilliant and clear British accent !!!!I like that!!!!
No, he had a clear AUSTRALIAN accent
Love you sir...!!
I have a video of me demonstrating the first experiment on my channel. It's not nearly as entertaining, though. Not much talking. Much smaller (cheaper) setup, too. Btw for those curious as I know I was, a klystron is a type of vacuum tube. That is, an amplifier similar in functionality to a transistor. Except this one amplifies radio waves and puts out microwaves. The horn shaped bit, called a waveguide directs the microwaves towards the reciever just like a horn directs sound waves.
Aula incrível! Poderíamos criar um canal com dublagem em português br
Fantastic.
thank you very much.
This was fantastic thanks so much.
Did I just watch a person bragging for 20 minutes straight? I have to admit, I thoroughly enjoyed!