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Excellent! I have a few Wilescos and a few Mamods - love all of them!

Yes, I remember that sphere when it was discussed in Physics World a few years ago. Not quite that close indeed! I really would not want to cut it in half but would be interesting to see what it looks like. Ultrasound would just produce an mess of an image I think. Adam Savage did a good job with the water jet cutting ua-cam.com/video/onZDAKJq6z4/v-deo.html I really feel that, whilst there must be lots of voids, dirt/oxide etc. the layers may well have got close enough to form metallic bonds. It was a fun project regardless and thanks as ever for your interesting observations. Do keep them coming!

Thanks for your kind comments. Any charge detector that relies on the presence of electric field lines would of course would read zero. One would have to be careful to check that you were not 'distorting' the closed surface as it were by introducing an object that would have to be able to communicate with the outside. Yes, as you say, school and university cupboards must be full of these dusty old items with many instructors having no idea what they are or what they were used for and the amount of skill and effort that went into making them! I have an old Archimedes' bucket and cylinder, and the spring balance to go with it which I must make a video of at some stage. Thanks again for watching and taking the time to comment.

Thanks Carol, so pleased you liked it. Hope it is not looking too dated by now. I have had one in the can for Oswestry for years and never got around to filming it! I do love Shrewsbury though!

Good question. Normally a tube with an electron gun has a strong vacuum in it to stop loss of energy and scattering of the electron beam. This one is rather unusual in that it has a small amount of helium in it to make the beam visible for educational purposes. Normally that would not be a good thing! Hope that helps and thanks for your excellent question.

@@AnthonyFrancisJones thanks for the answer

@@Sehmuzza Pleasure and thanks for watching!

Thanks very much for your kind comment. Yes you are right, not an easy one to explain and I almost got into a bit of a tangle myself as it is all done in an hour or so of my lunchtime break! Hopefully got the general theory of this experiment across - one which I think most people/teachers have not seen or heard of.

Thanks for this and you are absolutely right on all counts. It would have made things much clearer (and for me too trying to keep my explanation going correctly as it is all done 'live', I do not use a script). And yes, my videos all started from simple classroom explanations but as they have got tricker they would benefit from added graphics which at the time of filming, Aug 2021, I was not really into or a fan of! Thanks as ever for your comments and glad you liked this rather forgotten experiment. More coming soon I hope!

That's a really good question and your guess is way out!! It is a old motor driven, relay controlled school (Griffin) centisecond timer! I should do a video on it! collections.st-andrews.ac.uk/item/centisecond-timer/1005577

Glenn, thanks for taking the time for such an interesting story. Yes you are right. Those of us that were brought up with computers that had visibly moving and interconnected parts have a much better understanding of what happens 'under the bonnet' (hood!) as it were. I remember as a pupil using the school's ICL mainframe and doing 'dir' requests and hearing the hard drives accessing a room away as the heads moved in and out on the massive drives and disk packs! Really good idea of yours to put switches onto the project to use it to demonstrate ASCII characters. I think I want to leave this board alone as it is just hanging together! I would probably break something! Have you seen my other videos on the magnetic core memory I have? I thing there were links in the description. Thanks again, it is comments and experiences that people like you share that make these objects come to life. Many thanks again, Anthony F-J.

Thanks Jakob. Glad you are enjoying it!

Thanks Ralph. That's really kind of you. I was trying to show something a bit unusual but interesting that perhaps does not have a lot of coverage on UA-cam already! I just never cease to be amazed by what you can do with these Teltron tubes!

Pleasure Mark and thanks for your continued support of the channel.

Thanks Lindsay! That's really kind of you. Glad you like the videos - made this one a while back but it's and interesting topic. Let me know if there is anything else that interests you that I might be missing and thanks for making it all worthwhile.

What is a cro

@@shivenprashar1427 It's a Cathode Ray Oscilloscope (CRO). Now they are usually just flat screens so may only be referred to as an oscilloscope. The device for showing rapidly changing voltages on a screen. Thanks for asking.

Thanks again Tony. If I had put a motor on it (it would probably have jammed!) I think the smoke demo would be less 'pulsed' due to the way I was turning the gears by hand. Bit of fun but not a build I want to repeat in the near future!

Yes, it is a badly worded question. Three values all in kbar. so A is 145kbar, B is 2x10^-5kbar, and C is 35kbar. So A is 145000bar, B is 0.145bar and C is 35000bar. So A, C, B in order of largest first but because of inverse relationship the answer order is B,C,A so answer is 3. Hope that helps! Keep studying hard!

@@AnthonyFrancisJones Should there have been a comma before kbar? I considered k bar for the last term only and took the others in bar so got option 2. And thanks a lot for replying I took 145 bar, 2×10^- 5 bar and 35 k bar So the order came to be B>A>C 😞😓

Yes, every value (unless it is a real trick question!) should have units with it, so go with kbar for all of the numbers in this case. Badly set question I would say! You have got it now though! It shows me that you understand the science really well but need to keep practising this type of question so you are used to the things they get up to! Not your fault!

@@AnthonyFrancisJones Thanks for the encouraging words. I actually took it to be a tricky question because if indeed kilobar was meant for the last value, most people would miss it. I took it that way because tricky questions are often asked in entrance exams. I was worried about my English grammar 😅

I had lots of ideas after school and ended up doing a form of Production Engineering. I then did a post graduate course so I could be qualified to teach physics. All good fun and none of this ever narrowed down the opportunities that I managed to get! Do a general engineering course and you can always specialise later unless you are really keen to do a specific one such as Mechanical or Electrical or Electronic, or Civil for example. All good courses lead to opportunities, many of which you can never plan for!

Great! Glad you liked it!

Yes, I love these old steam toys and they are great for demonstrating engineering principles too!

Thanks. It's interesting stuff isn't it!

Thanks! Not been a very popular video but it was a bit of fun and glad you liked it!

Sorry about that. I have had a listen through again and don't seem to hear what you refer too. I know my large lab has quite an echo and it was filmed during the working day in a school. I now film with a tie clip mic which helps. Any further suggestions greatly received.

Great to hear that you have a Landy now and do please get out there and enjoy it. I find mine one of the easiest and lightest vehicles to drive but it is only 2WD. Get the brakes sorted and some slack taken out of the steering and it will be a joy to drive but drive slowly! Our type 2 VW camper used to take huge concentration as it wandered all over the place. Got the steering sorted and it became so much easier! Hope you have fun with your 2A. Let us know how you get on! If only I had the time to get out again...!

@@AnthonyFrancisJones Another UA-camr is driving around the world in his Defender. He stopped here in California last fall and filmed my Land Rover. If your interested , it is “LandyAndy4X4” Castle Air Museum part 2, towards the end of the video. Let me know what you think! Cheers👍

Great, I will have to have a look and be jealous!

@@AnthonyFrancisJones Haha! I’m the one who is jealous.👍

@@calsurflance5598 Just seen it and what a lovely Series 2 you have. In your weather I think it will probably last forever and cost you nothing in repairs... but then again it is a Land Rover! Do use it and you will turn heads everywhere you go. It looks fantastic and, as you say, keep it looking like a working vehicle and not something that people are too frightened to even touch!

Thanks Jo. Did not quite come out as I wanted. My bubbles were a bit on the big side! But had to film it quickly and it was a bit of fun regardless! Thanks for watching and your kind comment.

Radek, thanks for this. Interesting what you say. I guess it is chaotic as the there is a limited) though massive number of outcomes that are bounded within limits rather than being capable of any outcome. I am working on a chaos video at the moment but I cannot get my analogue electronics to perform the correct differential equation integrations to show the Lorenz Attractor or similar. I will get there at some point I hope! LEDs, I did not realise it would affect coupling and therefore synchronisation. That's interesting! I realise that with multiple resistors the current through any LED should be fairly fixed when it is on obviously assuming a much lower internal resistance of the power supply! Thanks for your interesting comments and for watching. Hope you will enjoy some of the other videos too!

@@AnthonyFrancisJones , yes, the Lorenz butterfly comes to my mind when I was writing about chaos. There is schematic he used, and I found it is also in The Art of Electronics the X Chapters, page 358. However you need an MPY634 or similar, and two of them. It is analog multiplier. With that re-synchronisation of blinking LEDs, it is my prediction based on the fact that blinking LED is an oscillator. When you find a way how to couple them strongly enough they must synchronise by definition. There is a nice video on YT somewhere, I guess by Veritasium or someone, and there an mechanical motronomes are used as oscillators. They behave exactly like the blinking LEDs and shortly desynchronised. Then same situation but the metronomes were on hanging desk, which could move, and by the coupling of that desk they synchronised.

@@AnthonyFrancisJones , a note to randomness a chaos. By my amateur understanding. Random system is a such system, where, even if you know all previous states, you can't predict next state of the system. Chaotic system is a such, when with a little knowledge about past you can very successfully predict next state. However the more to the future you are trying to predict, the less success and bigger error you get. Typical chaotic system is 3 body problem. Or on steroids, movement of bodies in Solar system. And chaotic system do not need to have attractor.

Thanks Radek. Yes my chaos circuit will be like Horowitz and Hills. The book of theirs I bought when I was at school predated the chaos chapter addition! I am sure I have made a simple mistake or solder bridge in my circuit but it is sensitive to initial conditions by not working! I remember the issue of clocks synchronising on a wall and also remember the paper on synchronising metronomes. I think it has been much copied on UA-cam. I think you may well be right about the LEDs - I will have to try a circuit. I do have one that has lots of LEDs in a cube with only one current limiting resistor and have not yet noticed synchronisation. I think they are so cheaply made that they may well synchronise and then immediately go out of sync again due to differences in their manufacture. Al interesting stuff!

I think you have got it just right there so thanks for this. I am glad that the video has resulted in such interesting discussions.

Cohen, not sure I follow your comment. Is there something you would like me to explain further or an idea that I failed to explain well? If so, do just ask.

You are unlikely to get paralysed but freezing of living cells is never a good thing - you can easily kill them and get frostbite! Also if you freeze your hand to the cold metal surfaces/tap you may be unable to turn it off - not a good situation to be in!

Thanks for this and a nice way of doing the experiment. If you don't get it too hot I guess you could put lycopodium powder or similar into the tube to show the nodes and antinodes as well! By the way I must do a video on the physics of Trevelyan Rockers at some stage!

Thanks Noah, yes that's right. These glazed items were not so common in the UK but were around a lot in the USA. Their more modern glazes look the same but do not contain the same additives. I don't have an example of original 'uranium' Fiesta Ware sadly but I love all the colours they did!

My pleasure! Glad you found it interesting.

Pleasure. Glad you found it helpful! Good luck with your studies.

Yes it does, probably billions of atoms but that is still a very small amount! The main thing is that the half life of the uranium in the glass is so long!

@@AnthonyFrancisJones do can we like melt the glass And then as uranium bight be denser so it will just you know do downwards I don't know I don't have like so much experience

No it is not in the metallic form in the glass. It is part of a oxide form of uranium and that would need some complex chemistry to extract as well as the end result would be very little U238.

@@AnthonyFrancisJones thank you By the way Any channels you would support for this type of chemistry and stuff or any books you would recommend

That's a tricky question as most of my ideas come from years of teaching and lots of varied sources! You might enjoy the amazing channels that are The Action Lab and Applied Science and perhaps Nile Red too. Books, again, my content is rather too spread out for any particular book. I did enjoy The Radioactive Boy Scout, a true story about a boy trying to build a nuclear reactor in his own house! I do have a collection of old school practical science books and they often have lots of interesting ideas in them. Sorry not to be more helpful but hope you continue to enjoy my varied output!

Yes, I think this is a good demonstration of fluorescence but not really radioactivity as the count-rate is so close to background with a GM tube. I don't think I have any of the vacuum tubes with this glass in it - used for large vacuum capacitors too. Most of my examples seem to use a special sintered glass like the CV2799. Schools (under licence) can still have sealed radioactive sources of an approved type but gas mantles are usually frowned upon due to the dusty nature of the Thorium Oxide. So much has changed in the years I have been teaching but I do hope children still see things demonstrated in a safe way. I have an old TEL-X-Ometer but need to fit a tube to it!

@@AnthonyFrancisJones yes indeed, dust from mantles would concern me too. Although that must have been common when they were extensively used. I remember seeing the TEL-X-Ometer as a student. The tubes appear now and again but seem pricey. It also took me back to a school lunch time experiment where my physics teacher and I tried to fog photographic film using just an old TV diode valve. Unfortunately, not an experiment that would be repeated in schools today.

Interesting! Yes, one has to be careful about that type of 'exciting' experimentation these days! Sounds like you had inspiring teaching regardless of the possible risks!

And also, UV fluorescence comes from _molecular_ bond right? so its related to Coulomb attraction of uranium nuclei but not really a nuclear phenomenon like decay

Geoffry, not quite, you are right it is not a nuclear phenomenon as it does not directly involve the nucleus. Nor is it due to bonding directly either. It is the electron configuration in atoms that is the cause. Simply, some atoms electrons can be promoted to a higher energy level when they absorb UV light and then the electron falls back via a number of lower value energy jumps emitting a photon of lower wavelength (green) light each time. I think in this case it is due to the ionic configuration of the uranium atom but I am not totally sure which electrons are responsible.

Geoffry, that is an interesting question. Vitrification (putting in glass) is used for high level nuclear waste and there are issues with embrittlement etc. I think the item would have long been lost/broken by then!

David. The radium in dials has a half life of around 1600 years so the paint binder falls apart and causes it to flake off well before then. The main decay is to Radon too! The glass is about 1BED (is that the correct unit abbreviation?). Perhaps '1 coffee' too! It is interesting that some people are disappointed about the radioactivity of this glass thinking it was made to be radioactive, however, it is just a byproduct of wish for a nice green colour. As you know there were many intentionally radioactive 'heath' items back in the day, to be avoided now! Thanks as ever for watching.

Thanks Frauke. I had great fun making it! Doing all the colours added to its look as well I think!

Thanks for the question. Each length has a different natural frequency so swings at a different rate/frequency. Short is higher in frequency than longer - a bit like strings on a piano. If they swing at different frequencies there will be a phase difference between them. i.e they will not always be in line with each other. But the weight and one of the pendulums (of the correct length) will always be swinging together at the same frequency but with a difference in 'position' that remains the same between them all of the time. So they are not in phase either but have a constant phase relationship. Hope that helps.

Yes, the finger licking method for separating paper lives on! I think if you press on a deck of cards the stretching has a similar effect. Something you might want to try. There is also the bending the pack back and forwards method that is often used to make counting piles of bank notes (if only...) easier.

Isaac, normally the green earth terminal is connected to ground (outside the building) and is therefore guaranteed to be at zero volts (potential). Typically we connect it to anywhere we want to be at zero volts or never to get higher than zero volts (for safety etc.). In this case I can 'dial up' a potential difference of up to 5000V on the red and black terminals with half the value always available on the blue socket. With this experiment it is the potential difference that matters not a value referenced to ground so I did not use the green socket. I would if there was a piece of metal etc. on the apparatus that I never wanted to go 'live' (above zero volts) for safety. Hope that helps a bit and thanks for your question but as ever, never play with this type of kit unless your are fully conversant with it and the risks associated too.

Thank for sharing and reminder，I already got an electric spark when I doing a expt about the matters of charged material ( Dutch foil) in electric field ， like an electric shock in winter 。 hard to avoid 🥲

I hate electric shocks even if normal static ones so I do all I can to avoid them!

Thank you, that's really kind. These were lessons for my pupils who were stuck at home during the Covid lockdowns so not flashy at all but I hope they explain the main points in as clear a way as possible. Glad you found it interesting. Many thanks for taking the time to comment.