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 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....
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.
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....
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.
Famous of course in Adelaide Father and Son. Proud of our Australian Nobel prize winner. That’s why Adelaide University has the Bragg laboratories. By the way Lawrence was born in Adelaide, Australia so this is the Adelaide accent for someone born late 19th century.
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.
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.
We'd like to think we're still carrying on the legacy of the greats who have come before, from Faraday and Davy to the Braggs and Longsdale. Whether you're interested in long-form or short-form science content, TH-cam exclusives or broadcast TV shows, our main channel uploads new content every week - th-cam.com/users/TheRoyalInstitution
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..
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
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.
Never seen various phenomenon of light shown so clearly. We have a shed load of CGI now but none do the subject justice in the way this presentation does. I wish I had known about this when my son was being taught physics as school.
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..
dayyyyyuuuuuuum, waves are waves after all! This is cool, maybe Im bias as I already knew most of it but dang I didn't know all these stuff. It's my first time seing that in action aside from visible light!
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.
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.....
This guy "Coates" made a great straight man: Rigid facies, never smiled, always immediately on cue. I laughed so hard I fell out of my chair here in the lab. Great teaching !!
Great spot. He appears on many such videos and was an unsung hero. He instinctively knew he was not the star of the show and so got on with the job classic style. Same thing happens in rock concerts too when a roadie comes flying in from stage left to catch a falling microphone stand etc, change guitar. Morecambe and Wise lampooned this kind of thing with the singer Shirley Bassey where they wore the obligatory brown labcoat used to denoe the role of the 'unsung'!
From (GOA) INDIA Lot of thank to Royal Institute of science London This is way of demonstration I am expecting from knowledgeable person and that is right way of teaching. Lots of thanks to sir Lawrence. That's why I didn't likes our Indian Education system. You should teach small small concept by demonstration and not quantity of syllabus quality Of syllabus is important.
It's partly a refined early 20th Century Adelaide accent which had been influenced by his educational environment. Most of the world uses roughly 50 Hz for its electricity grids. North America is one of a minority of places which use 60 Hz instead. Each has some advantages and disadvantages. For instance, coils, motors and transformers can be slightly smaller at 60 Hz, but transmission losses are lower at 50 Hz.
This is an interesting video indeed. I would have liked to have heard Sir Lawrence Bragg mentioning the fact that electromagnetic waves are to be looked upon as any other formation of ELECTRIC LOOPS and MAGNETIC LOOPS linking each other. For any machine to work, an ELECTRIC loop MUST link at right angle with a MAGNETIC loop.This relation must also exist for DC conditions. In AC conditions, the loops are oscillating but they are still LOOPS, just like two wedding rings, linked, CURLING each other at right angle. These loops were clearly "seen" when he used the transformers working at 50 Hz. The electromagnetic wave in the waveguide and the horn he used, were also loops of magnetic fields linking loops of electric fields. and while in the waveguide the loops of magnetic fields were always in the waveguide space, while the electric loops flowed along the walls of the waveguide and crossed the rectangular waveguide across its flatter face. These loops called the E/M loops kept on creating each other as they left the waveguide horn. What was shown as LOOPS in the transformer, remained as loops in the air between the transmitter and receiver antenna . I wish he said that. When he showed the induction coil experiment he said "When I move the magnet INTO the coil..............." Well of course, he did say that he moved the magnet INTO the coil, but the magnetic lines parallel to the motion did not generate the voltage in the coil by the magnetic lines moving INTO the coil parallel with the motion as what happens is, that more magnetic lines crossed RADIALLY to fill the centre, to cause a rate of change of magnetic flux, which crossed the coil at right angles in a radial manner. I would have been careful when using the word INTO the coil at 2:30, as that suggests that the magnetic line moved parallel with the central axis of the coil and that sort of movement does not generate a rate of change of magnetic flux. The magnetic lines parallel with the movement, "moved radially" to cause the rate of change of magnetic flux linking the coil. If he used a rotating generator that is how the magnetic flux would have moved into the coil, sideways. In fact the rate of change of magnetic flux is clearly shown by the meter as when the magnet was stationary inside the coil, the meter returned to zero . When he withdrew the magnet from the coil the magnetic flux crossed out in a radial manner giving the deflection in the other direction. The magnetic field around the end of the magnet he used is rather complex I wonder how many viewers deciphered " INTO" and "OUT OF" in the right meaning of rate of change of magnetic flux. Again, when he had the coil picking up the nails, 3:13 he was absolutely correct when he said, " we make electrons RUN AROUND this wire", as that suggest the ELECTRICAL LOOP that I spoke about. But when at 2:22 his finger went straight down showing the magnetic field went down into the coil, there he should have said that the electrons going around the loops of the wire would create magnetic loops going AROUND the coil through its central orifice/ opening and not just straight down. When he showed the standing waves using the mechanical arrangement at 16:36 Sir Lawrence Bragg said that each wavelength included two LOOPS. Again I am afraid to say that the model is not an exact model of an electromagnetic wave as the Potential Energy is stored in the rubber at the central axis and the moving weights the kinetic energy and there are no LOOPS anywhere in that model. Those we see are not loops, but a sinusoidal shape where the intensity of the motion goes positive and negative but not in a loop. In an electromagnetic wave each wavelength does have two full LOOPS but they are not in the forms Sir Lawrence has shown. An electromagnetic wave proceeds to use the loops as shown by that transformer experiment where the coils included the FULL ELECTRICAL FIELD OSCILLATING LOOPS and the iron paths contained THE FULL LOOPS OF THE OSCILLATING MAGNETIC FIELD . It is E/M linked and curling loops that reaches the receiver from the transmitting antenna. Loops, always full loops. When at 1:05 he described waves using matter and electrons and electromagnetic fields do not use any matter, he should have hinted that the VOLTAGE at the antenna would create a voltage PRESSURE and it is the voltage field that can be radiated into space where there is no matter. But voltage pressure on its own will arrive at distant points but will never carry any information in that CONSTANT pressure state. But the RATE OF CHANGE OF PRESSURE which is related to RATE OF CHANGE OF ELECTRIC FIELD well now the rate of change of electric field is what one can use at a distance . A whip or a loop antenna can have fields due to voltage pressure or current flow in them but it is the rate of change of the Electric Fields or Magnetic fields LOOPS that can cover the distance in space where there are no particles, What is more, it is the RATE OF CHANGE OF ELECTRICAL AND MAGNETIC FIELD THAT CAN CARRY OUR INFORMATION. Well, really the rate of change of an electrical loop is really a special form of current , a special current, a little different from a conduction current, the latter moves where there are particles but the current due to the rate of change of electric field exist where there are no particles. Recently I tried to make an electro-mechanical model of an electron whose characteristic will cause the "model " to behave as the real electron behave. In this model I had to include, Mass, negative charge, but not in one central mass, but distributed negative charges on a flexible membrane which will cause the many elemental negative charges to oscillate on this flexible membrane, Well, as the elemental charges oscillate they create a circular magnetic field around them and as a whole the mode of vibrations are similar to the higher modes of vibrations in a tuned high frequency cavity. These voltage vibrations creating the electrical and magnetic looped fields are biased in their voltage potential because of the accumulated negative charge of the whole electron. When stationary the mass and charge and the biased E field are available to the outside world but not the magnetic curls in different orientations, When the electron as a whole is moved by shooting it or under the influence of an external electric field or when an external magnetic field is moved towards it, the magnetic loops line up and the moving electron will create a curling magnetic field with its direction of motion felt in the outside world. I have tried this model to explain the working of Motors, Generators, transformer, back emf in inductances, mutual inductances, capacitors , heat radiation in resistors , light emission from red hot metals , It seem that in its form, my model can show mass characteristics and also wave motion characteristic. I should publish this, as through its simplicity, it offers quite a few explanations why the electron behaves as it does in any of what Sir Lawerence Bragg described in this video.
holy crap thats a lot of writing, isaved this on a docx ill read it later thanks for taking the time to explain concepts that are important and elusive
Hi, I read your comment and you seem well versed in field theory. Firstly, can you define an electron and what is a negative "charge". In your model, are you not describing a capacitor? Cheers
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.
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. ❤
It would be interesting to see a precise date for this recording. As far as I can tell, it must have been somewhere between about 1962 the year after the first proposal of these audience-free recordings, and 1971, the year of his death. Maybe around 1965?
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
We definitely agree but are very limited in terms of resources. We were very kindly provided with funding to digitise these incredible snippets of archival footage but it didn't quite cover the cost of creating subtitles. Fingers crossed we'll get to unlock some soon. We've also enabled community contributions on all out videos, where some kind souls have volunteered their time and talents to provide closed captions.
@@VoidHalo Yes! We have community contributions turned on for our videos, so you can click on the three dots under the bottom right corner of a video and select 'add translations' in the drop down. For this video, it would take you here - th-cam.com/users/timedtext_video?v=Vwjcn4Vl2iw&ref=share
Of the various comments, I believe yours is the only one that touches on the most important aspect: namely, that "one computer simulation today" cannot possibly compare with a demonstration like his that uses a wide variety of beautiful physical equipment!
The Perspex Lens experiment blew me away, I understand that visual light would have produced a similar result but here he was using much longer waves than those of light. This is going to change the way I think about radio signals bouncing around the Earth, and how the ionosphere and water vapor act like a kind of lens.
Thanks for posting this for free public consumption; it is really remarkable. Quick Q: is there a modern equivalent to the Klystron apparatus used here? Put another way, how would is this demo be replicated today?
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.
I wish my physics teacher had been of the caliber of Sir Bragg and Professor Laithwaite, then maybe I would have learned something back then, and not only just now.
At 15:45 there is difraction. As the waves pass through the holes, they are deviated an angle and interact constructively and destructively, creating an interferometry pattern.
If he understood what he was demonstrating rather then just showing us what is happening, he would have another Nobel peace prize. And physics as we know it would be turned on it’s side.
![PASULOL รามเกียรติ์ ตอนที่ 4 นนทกพบรัก [Ramakien Ep.4: Nonthok in love]](http://i.ytimg.com/vi/tMUQgmZzf_A/mqdefault.jpg)
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..
South of the Sahara worse. Bad teachers can make people hate a good subject
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
He was a great teacher at Adelaide University, hence the last called Bragg
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.
Famous of course in Adelaide Father and Son. Proud of our Australian Nobel prize winner. That’s why Adelaide University has the Bragg laboratories. By the way Lawrence was born in Adelaide, Australia so this is the Adelaide accent for someone born late 19th century.
Excellent - no graphics, no animations. Just good physical explanation. This really gets the point across..
Lol what's your problem with graphics or animations
Actually seeing the experimental apparatus used to investigate these phenomena is truly eye opening.
What Sir Lawrence Bragg demonstrating is well understood: He demonstrated the deference between Education and Learning. Hats off to him in respect.
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.
It's butefull lesson. Благодарю тех кто выложил. Такие лекции заставляют задумываться над многими процессами .
Что за излучатель в его опытах не подскажешь?
That visualization of a wave with moving parts is amazing
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.
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.
Why isn't science being explained this elegantly anymore nowadays?
We'd like to think we're still carrying on the legacy of the greats who have come before, from Faraday and Davy to the Braggs and Longsdale. Whether you're interested in long-form or short-form science content, TH-cam exclusives or broadcast TV shows, our main channel uploads new content every week - th-cam.com/users/TheRoyalInstitution
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'
I'm fortunate to have viewed this presentation.
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
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.
Never seen various phenomenon of light shown so clearly. We have a shed load of CGI now but none do the subject justice in the way this presentation does. I wish I had known about this when my son was being taught physics as school.
Those were great demonstrations.
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..
Fantastic presentation on EM energy and waves. Thanks.
Amazing!! With zero mathematics, a rare gem video making us watch the actual behaviour of invisible. Grear professor.
dayyyyyuuuuuuum, waves are waves after all! This is cool, maybe Im bias as I already knew most of it but dang I didn't know all these stuff. It's my first time seing that in action aside from visible light!
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?
Btw... this Klystron was rocking a solid 30GHz ! Stunning to think about that this has been allready done in the 50's.
The way this is filmed is incredibly therapeutic lol
Genial! Una de las explicaciones más claras de las bases del electromagnetismo que he visto. Realmente excelente!
This video should formally become a part of school
curriculum
Thank you Sir for such a great lecture and your contribution in science education.
Finally feels confident of what i thought i knew.
Thank you, an incredible illustration of electromagnetism and wave propagation. The video is a gem.
Superb presentation. I am a radio person and I still learned and relearned this important subject.
You changed my way of thinking about EM waves...really better than modern explanations with animation
Very proud of Lawrence Bragg, Adelaide Australian born and educated. He and his father put Adelaide Uni on the map in Physics
This is a fine demonstration why fundamentals need to taught by great masters and not grad students.
Very informative and easy to grasp. This British gentleman is a good teacher indeed.
@ianl707 This ageism is annoying and *not* a good indicator if someone is smart, a good teacher or not.
Maybe not the most charismatic gentleman but I do love all the demos! Helps the simple mind (like my own) grasp these abstract phenomena.
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.....
How beautifully demonstrated. Good old days
Back in time things were real and universities produced real engineers.
This guy "Coates" made a great straight man: Rigid facies, never smiled, always immediately on cue. I laughed so hard I fell out of my chair here in the lab. Great teaching !!
Great spot. He appears on many such videos and was an unsung hero. He instinctively knew he was not the star of the show and so got on with the job classic style. Same thing happens in rock concerts too when a roadie comes flying in from stage left to catch a falling microphone stand etc, change guitar. Morecambe and Wise lampooned this kind of thing with the singer Shirley Bassey where they wore the obligatory brown labcoat used to denoe the role of the 'unsung'!
Great public demonstrations!
This is the best explanation teachers couldn't do today
Wow ... a wonderful find ... of real quality ... both this video and your many archives. Thank you.
This really is amazing. It visualises something invisible and helps understanding electromagnetic waves. Thanks a lot.
From (GOA) INDIA
Lot of thank to Royal Institute of science London
This is way of demonstration I am expecting from knowledgeable person and that is right way of teaching.
Lots of thanks to sir Lawrence.
That's why I didn't likes our Indian Education system. You should teach small small concept by demonstration and not quantity of syllabus quality
Of syllabus is important.
Really a privilege to learn from a Nobel Prize.... And yes, he´s the one (with his father) of the Bragg´s Law !
Got to hand it to the Royal Institution Of Great Britain, they make some very informative videos!
50 Hz ?? ( @ 4:56 ) NOW the British accent MAKES PERFECT SENSE
This is ABOVE and BEYOND anything, and everything I have viewed on TH-cam thus far
It's partly a refined early 20th Century Adelaide accent which had been influenced by his educational environment. Most of the world uses roughly 50 Hz for its electricity grids. North America is one of a minority of places which use 60 Hz instead. Each has some advantages and disadvantages. For instance, coils, motors and transformers can be slightly smaller at 60 Hz, but transmission losses are lower at 50 Hz.
Wow!! I would love to have this class at high-school!! 👏
This is an interesting video indeed. I would have liked to have heard Sir Lawrence Bragg mentioning the fact that electromagnetic waves are to be looked upon as any other formation of ELECTRIC LOOPS and MAGNETIC LOOPS linking each other. For any machine to work, an ELECTRIC loop MUST link at right angle with a MAGNETIC loop.This relation must also exist for DC conditions. In AC conditions, the loops are oscillating but they are still LOOPS, just like two wedding rings, linked, CURLING each other at right angle. These loops were clearly "seen" when he used the transformers working at 50 Hz. The electromagnetic wave in the waveguide and the horn he used, were also loops of magnetic fields linking loops of electric fields. and while in the waveguide the loops of magnetic fields were always in the waveguide space, while the electric loops flowed along the walls of the waveguide and crossed the rectangular waveguide across its flatter face. These loops called the E/M loops kept on creating each other as they left the waveguide horn. What was shown as LOOPS in the transformer, remained as loops in the air between the transmitter and receiver antenna . I wish he said that.
When he showed the induction coil experiment he said "When I move the magnet INTO the coil..............."
Well of course, he did say that he moved the magnet INTO the coil, but the magnetic lines parallel to the motion did not generate the voltage in the coil by the magnetic lines moving INTO the coil parallel with the motion as what happens is, that more magnetic lines crossed RADIALLY to fill the centre, to cause a rate of change of magnetic flux, which crossed the coil at right angles in a radial manner. I would have been careful when using the word INTO the coil at 2:30, as that suggests that the magnetic line moved parallel with the central axis of the coil and that sort of movement does not generate a rate of change of magnetic flux. The magnetic lines parallel with the movement, "moved radially" to cause the rate of change of magnetic flux linking the coil. If he used a rotating generator that is how the magnetic flux would have moved into the coil, sideways. In fact the rate of change of magnetic flux is clearly shown by the meter as when the magnet was stationary inside the coil, the meter returned to zero . When he withdrew the magnet from the coil the magnetic flux crossed out in a radial manner giving the deflection in the other direction. The magnetic field around the end of the magnet he used is rather complex I wonder how many viewers deciphered " INTO" and "OUT OF" in the right meaning of rate of change of magnetic flux.
Again, when he had the coil picking up the nails, 3:13 he was absolutely correct when he said, " we make electrons RUN AROUND this wire", as that suggest the ELECTRICAL LOOP that I spoke about. But when at 2:22 his finger went straight down showing the magnetic field went down into the coil, there he should have said that the electrons going around the loops of the wire would create magnetic loops going AROUND the coil through its central orifice/ opening and not just straight down.
When he showed the standing waves using the mechanical arrangement at 16:36 Sir Lawrence Bragg said that each wavelength included two LOOPS. Again I am afraid to say that the model is not an exact model of an electromagnetic wave as the Potential Energy is stored in the rubber at the central axis and the moving weights the kinetic energy and there are no LOOPS anywhere in that model. Those we see are not loops, but a sinusoidal shape where the intensity of the motion goes positive and negative but not in a loop. In an electromagnetic wave each wavelength does have two full LOOPS but they are not in the forms Sir Lawrence has shown. An electromagnetic wave proceeds to use the loops as shown by that transformer experiment where the coils included the FULL ELECTRICAL FIELD OSCILLATING LOOPS and the iron paths contained THE FULL LOOPS OF THE OSCILLATING MAGNETIC FIELD . It is E/M linked and curling loops that reaches the receiver from the transmitting antenna. Loops, always full loops.
When at 1:05 he described waves using matter and electrons and electromagnetic fields do not use any matter, he should have hinted that the VOLTAGE at the antenna would create a voltage PRESSURE and it is the voltage field that can be radiated into space where there is no matter. But voltage pressure on its own will arrive at distant points but will never carry any information in that CONSTANT pressure state. But the RATE OF CHANGE OF PRESSURE which is related to RATE OF CHANGE OF ELECTRIC FIELD well now the rate of change of electric field is what one can use at a distance . A whip or a loop antenna can have fields due to voltage pressure or current flow in them but it is the rate of change of the Electric Fields or Magnetic fields LOOPS that can cover the distance in space where there are no particles, What is more, it is the RATE OF CHANGE OF ELECTRICAL AND MAGNETIC FIELD THAT CAN CARRY OUR INFORMATION. Well, really the rate of change of an electrical loop is really a special form of current , a special current, a little different from a conduction current, the latter moves where there are particles but the current due to the rate of change of electric field exist where there are no particles.
Recently I tried to make an electro-mechanical model of an electron whose characteristic will cause the "model " to behave as the real electron behave. In this model I had to include, Mass, negative charge, but not in one central mass, but distributed negative charges on a flexible membrane which will cause the many elemental negative charges to oscillate on this flexible membrane, Well, as the elemental charges oscillate they create a circular magnetic field around them and as a whole the mode of vibrations are similar to the higher modes of vibrations in a tuned high frequency cavity. These voltage vibrations creating the electrical and magnetic looped fields are biased in their voltage potential because of the accumulated negative charge of the whole electron. When stationary the mass and charge and the biased E field are available to the outside world but not the magnetic curls in different orientations, When the electron as a whole is moved by shooting it or under the influence of an external electric field or when an external magnetic field is moved towards it, the magnetic loops line up and the moving electron will create a curling magnetic field with its direction of motion felt in the outside world. I have tried this model to explain the working of Motors, Generators, transformer, back emf in inductances, mutual inductances, capacitors , heat radiation in resistors , light emission from red hot metals , It seem that in its form, my model can show mass characteristics and also wave motion characteristic. I should publish this, as through its simplicity, it offers quite a few explanations why the electron behaves as it does in any of what Sir Lawerence Bragg described in this video.
I'd like to hear more about your model
holy crap thats a lot of writing, isaved this on a docx ill read it later thanks for taking the time to explain concepts that are important and elusive
@@AntonioTFernandez on the other-side of the planet there is someone like u who did the same.. and its me
Hi, I read your comment and you seem well versed in field theory. Firstly, can you define an electron and what is a negative "charge". In your model, are you not describing a capacitor? Cheers
I'm sorry, but that's just a load of babble.
This is too much for just one video 🎉🎉🎉thank you so much best science video ever watched on TH-cam by me
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.
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.
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!
It would be interesting to see a precise date for this recording. As far as I can tell, it must have been somewhere between about 1962 the year after the first proposal of these audience-free recordings, and 1971, the year of his death. Maybe around 1965?
In my school age if I could have this kind of teacher I could have become a great scientist
Wonderful piece of experimental physics. Formulas can never teach this.
this video series is a great series on experimental basis for chemistry
The best physics lesson I ever had. Thank you.
Incredible teacher. Such a clear demonstration, beautiful apparatuses. mechanical heaven for me. tnx.
superb demonstration and experiments
Great Video many thanks
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
Did I just watch a person bragging for 20 minutes straight? I have to admit, I thoroughly enjoyed!
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
Interesting to see demonstrations! Thank you.
Oh my lord give me more knowledge and wisdom. This video is well presented and got me more excited to purse master in Communication wireless.
I was just there last year standing where great men have demonstrated their machines
Quite brilliant demonstrations! Thanks for posting!
No captions? This is surprising for RI. People with hearing problems should be able to enjoy these.
We definitely agree but are very limited in terms of resources. We were very kindly provided with funding to digitise these incredible snippets of archival footage but it didn't quite cover the cost of creating subtitles. Fingers crossed we'll get to unlock some soon. We've also enabled community contributions on all out videos, where some kind souls have volunteered their time and talents to provide closed captions.
Is there any way to volunteer to add captions?
@@VoidHalo Yes! We have community contributions turned on for our videos, so you can click on the three dots under the bottom right corner of a video and select 'add translations' in the drop down. For this video, it would take you here - th-cam.com/users/timedtext_video?v=Vwjcn4Vl2iw&ref=share
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
Супер! Красивые опыты. Сейчас одна компьютерная симуляция.
Of the various comments, I believe yours is the only one that touches on the most important aspect: namely, that "one computer simulation today" cannot possibly compare with a demonstration like his that uses a wide variety of beautiful physical equipment!
The Perspex Lens experiment blew me away, I understand that visual light would have produced a similar result but here he was using much longer waves than those of light. This is going to change the way I think about radio signals bouncing around the Earth, and how the ionosphere and water vapor act like a kind of lens.
Excellent DEMONstration.
In fact all of these good videos should become part of a course in colleges
it's amazing explains .. thank you Ri Archives
Good demonstration about electromagnetic waves. Thanks for the video.
Aula incrível! Poderíamos criar um canal com dublagem em português br
Omg the focus lens blow my mind
Thanks for posting this for free public consumption; it is really remarkable. Quick Q: is there a modern equivalent to the Klystron apparatus used here? Put another way, how would is this demo be replicated today?
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.
I wish my physics teacher had been of the caliber of Sir Bragg and Professor Laithwaite, then maybe I would have learned something back then, and not only just now.
It's very important video...
Such a fine demonstration !
Brilliant and clear British accent !!!!I like that!!!!
No, he had a clear AUSTRALIAN accent
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.
Why on Earth we don't have a professor like this?
true knowledge is pristine and clear
i wish schools where like that in my age now. Amazing Video sir
Glad to have found this wealth of information
This was amazing learning
Thank you ❣️
Bravo! Well done, old boy!
Wow grabe! I learned a lot thanks to this channel...
Marvelous presentation
At 15:45 there is difraction. As the waves pass through the holes, they are deviated an angle and interact constructively and destructively, creating an interferometry pattern.
Many thanks for sharing this pearl of wisdom
Bragg apears to be a very humble man.
If he understood what he was demonstrating rather then just showing us what is happening, he would have another Nobel peace prize. And physics as we know it would be turned on it’s side.