Magnetism #2 - with Sir Lawrence Bragg

The concept of the magnetic field is further developed by Sir Lawrence in his description of Oersted's great discovery of the early nineteenth century: the relationship between magnetism and electricity.
The proof of this relationship is shown in a number of fascinating demonstrations. Sir Lawrence describes the magnetic properties of iron, and in a series of experiments illustrates its behaviour when subjected to the influence of a magnetic field. 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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[@faustdownunder]

Brilliant. Younger viewers will never forget the man hanging at just an electric magnet.

[@Shania-fg5rp]

i admire the quality and consistency of your content!

[@mathematics5573]

by golly. this is amazing. Bragg was very eminent. Nobel prize. Royal Medal. Copley medal. Braggs law.

[@ToolsAandLogic]

great explanation, excellent work royal institution

[@tolifeandlearning3919]

Great lectures

[@2788maroof]

Great science video......

[@allistarcenter3]

Thank you for these videos!!!"

[@sanjayphysics12]

Interesting

[@AntonioTFernandez]

*TAPS into the magnetic field*

[@KhangTran-sl3yb]

Great video. Thank you so much, Sir. . . Joke side: 1 minute of monument for the sawblade...

[@MuhammadBilal-tj8di]

can some one till me how the electromagnetic circuit work in the case of hanging man plzzzzz

[@gramps717]

why the iron just attracts when electrified why not repel when electricity is added

[@JChampion-sm6iu]

How would a build a magnetic field as strong as when the man could hold himself on the first time

[@dabay200]

I was confused by Bragg's demo of the iron rod - it seemed no different to after he hit it with a hammer it was influencing the compass both before and after.

[@comic4relief]

Dinal Abay at 13:32 the poker repels the needle

[@luistorh]

Before, *both poles of the compass were attracted* by the rod, which became slightly magnetized by the compass's field itself. After hitting the rod, it got magnetized by the earth's field, which causes the *repulsion of one of the poles* in the compass. The corresponding attraction by the other pole was not shown.

[@scienceisweird546]

when that men hang up at that electro magnet my reaction was like that " whaaaaaaat theeeeeee fuuuucccccc "

[@wrichik_basu]

Is there any way I can edit the subtitles? I have no intention other than helping out the Ri. There are some obvious mistakes in the subtitles created by KZbin automatically, and if they can be edited, I think it will be helpful for the viewers.

[@RiArchives]

Hi Wrichik, that would be lovely, thank you! If you click on the three dots right under the video, it gives you options of either opening a transcript or adding translations. If you click 'Add translations' it will open the auto generated ones and lets you fix them. Or you can 'switch language' at the top and submit in a different language. Thank you so much for your help!

[@wrichik_basu]

The greatest problem is that, this cannot be done from the youtube app. But I'll start of soon.

[@Kalumbatsch]

@@wrichik_basu Any progress so far?

[@arthurriaf8052]

Could you say the magnetic field is almost like a perpetual motion? It can be started and stopped but once started it continues forever? The motion is the fields continuing after the powers is shut off. Does a permanent magnet loose its magnetic field over time? Art👽

[@maciejnajlepszy]

Magnets are not as permanent as they are called, they lost their field over time. And they are not a source of power, just like the gravitation force isn't either.

[@stuffoflardohfortheloveof]

Brill…..again

[@Khumry]

law of the squares dr john sireal

[@thelifeanddimension]

If earth is a big magnet Why we still aren't able to make levitating vehicles

[@Khumry]

nicola tesla 369 124578