High-voltage physics - with David Ricketts

[Music] [Applause] this is the first demo so Mike would you come out and give me a hand so my little Rod here is charged and my little butterfly is charged with the same polarity and it floats because like charg is repel there you are Mike see if you can keep it going there you go it is harder than you think yeah that's a trick we learned now he's got a white pipe I have a different pipe and I'm rubbing it with a very scientific plastic bag no there you go oh okay all right all right let me give

you a hand let's see if we can get that going okay it's a bit tricky y now good job Mike now his is repelling but look at mine mine is attracting a little higher you see that my pipe is oppositely charged oppositely charged has attracts the same charge repels all right fantastic thank you Mike so um thank you so what was I doing there I was busy we were rubbing this pipe and what we were doing is we were charging it up using a method known as tribo electric effect tribo being related to frictio

n and I've got a beautiful demonstration ball this is my molecule when I rub it really really hard the electron comes off and I've got a positive ion and I've got a negative electron and that is what creates the charge it's from the friction of just removing these two that are here and I will put my molecule back and so what's interesting is that we can create positive and negative charge using this method of friction now throughout the talk today I'm going to use this little wand it has two lit

tle colors blue and red what they do is they signify that there is charge and that that charge of whether it's a red polarity or it's a blue polarity all we care about is like charge repels opposite charges attract so I have here a polystyrene two polystyrene plates and I'm going to rub the left one with my fur and I'm going to rub the right one with Teflon and let me see if I can get my stick in here oh I may have to rub again so today was the worst day of all days in London to do static electr

icity examples that's blue do you see the red that's not a good enough red let's see if we can do better no we're not getting the red the Blue's coming back on so let's try the this one more time we did see a little bit of a red earlier I'm just going to switch wands to see if this one's a little bit more sensitive oh you see a little bit of red you saw red come on all right yay okay thank you very much so the question is which one's positive and which one's negative and this is a question that

we think is scientific but in fact it's not most people think about polarity in charge related to the electron well the electron wasn't discovered until the very late 1800s so in Benjamin Franklin's time when he was inventing the name of positive and negative charge he had no idea about the electron so he just had to guess and his guess was glass when you rub glass with silk in this case I'm going to do Teflon whatever it comes out is positive and that is how positive is defined now let's see wi

ll it do for me well either one there we go do you see the red I'll try it one more time perfect so red is positive that is how positive is defined by a glass rod and silk in this case I use some Teflon so you noticed here that I could create positive or negative on the same material by using two different materials and in fact what they did is they took all kinds of materials they rubbed them together and they went to see which one was positive with respect to the other one and they just put to

gether what's called a tribo electric series you can look it up on Wikipedia and it goes through which materials you rub with which matal that get positive or negative now what's interesting is the word electricity electricity comes from the Greek word for Amber Amber the sap from the tree that hardens they would take Amber and they would rub it and that would create a static charge and that is where electricity got its name and that's also where electron got its name is for the Greek word for A

mber in fact Michael Faraday In This Very theater would take ceing wax and rub it against something to create a static charge and this is the first way that we as humans began to generate electricity today's talk is very simple we're going to start with low voltage a few thousand volts and we hope to end Today's Show with over 1 million volts if you're wondering how can I demonstrate 1 million volts it will make a spark one meter long I hope that demo works all right so now I want to show you a

couple interesting things we can do with electricity I've shown you the tribo electric the next thing I want to show you is induction so gets too much there so what is happening is my charge here is inducing a polarity on the can where the opposite charge is on one side and the uh like charges on the other and to share that with you I actually have this balloon here and it in fact will operate just like the can so what we have is this is charge negative which means all of the negative charge run

s to the other side and that leaves this side positive opposite charges attract the positive is then attracted to my negative stick as we can see right there so what I do is I induce a difference in charge and this difference in charge is going to be one of the ways that we start to generate higher and higher voltages now I have just shown you that demo I saw that demo myself uh when I was young and I asked myself how do I know he's just not making it up I mean really did any of you see the elec

trons run over to the other side are the can no so I said to myself how do I prove that this is really what is going on and so I would like to demonstrate that for you so I have here a Vander graph generator you may have seen it before I will explain how it works later for right now I just wanted to generate a bunch of charge for me and sorry about that so my little charge wand here I'm just going to turn it on turn on my wand it is red everybody see it's red okay so what I'm going to do is I'm

going to take two pieces of metal and what we're going to do is let me just do it the opposite oh there we go here we go so if red is negative all the negative charge will want to go over here and this will become positive over here key thing is you notice they're touching right they're just like the can one continuous piece of metal so what I'm going to do is I'm going to take both of these off and to touch them together and now I told you before a field was induced you shouldn't believe me how

can I prove it to you I separate the two and if this really had now let's go back in ah there we go this was red let's reset the red these things go a little crazy when this is on let bling the red let's reset there we go we get a blue on both of these now on both of those so I'm going to reset it just does not like you know what I'm going to do put them close going to separate let's see if that makes this behave better that was red that was blue all right blue red will it come back on no one c

ome back on it's already lost so there I've separated the charge into two pieces and this is how we're going to generate higher voltages because we can induce charge and then we can separate things now um I want to show you the next way that we generate high voltages and it's called electr forus and it is using the induction that we just spoke of so what I'm going to do is take my fur and to rub this and now let's see what we get blue nothing I'm going to put this on top I just put nothing on Bl

ue do I have any more charge than the original blue no so I should be able to go in and see my blue unless it's leaked off already there we go I was just touching that can we get a blue can we get a blue from anybody here can we get there we go we got a blue there's our blue now what I'm going to do is I'm to come in with this stick and all I've done is I've taped a neon bulb to the end of the stick and when I get a spark you can't see it so I'll just say ouch but I wanted to show you one spark

so you know we did get sparks can we take all the lights down all the lights down do you see it okay so what I've done now is I've taken all of the charge off of here so there's no charge I'm lying to you here as I bring things around so there's no charge on this and here's the question is there really no charge or do I now have an equal and opposite charge on the metal plate as I did on the polystyrene plate if I take them apart see if I can measure blue red blue red right so what I have done i

s I've actually created blue charge by letting all of the red charge that wants to repel go into my hand and then what is all left is the blue charge here and so in doing that I'm able to create charge on a separate device now that was a little bit of a spark there let's just pick this back up I can touch I could transfer I could touch you can't hear it but a spark spark spark you getting the idea so I could actually do this all day and if I had a good insulator and the charge wouldn't disappear

I could do this for the rest of of my life okay now people sometimes say well isn't that free energy free electricity no have you not seen me touch it move it touch it move it I'm doing the work I am pumping the charge in and out and I'm doing the actual work and that's how we get the work but we can transfer that out of here so now what's interesting is I want to show you with this little device and pull this up we have a roaming demonstration camera here uh and I think Mike's going to try to

zoom in on this so what I want to do is I want to charge this up could we get the theater uh the oh this is good you guys can see me and now I'm going to change this first of all let's reset this to zero okay we agreed zero oh I did it backwards it's got to go down touch transfer and notice it stays at about 1.7 right don't look at the one that changes that's just because I'm moving the plate back and forth 1.4 1.7 you may say well maybe you lost all your charge here so I'm going to put a lot mo

re on transfer it over oh we got to two that was pretty good but I really can't get above 1.7 or two now why is that it's because I can only transfer charge let's go to Black when the uh potential of this is higher than the potential of this the potential for electricity is voltage so when this has a higher voltage I can transfer charge when they're at the same potential I can't and so what I have here just to kind of illustrate this and Dan could you take the plinth away thank you so I have two

uh beakers of water here and I've already pre- siphoned them and what I'm going to do is I'm going to pour water into here and the water is charge and the charge is being transferred from one to the other through this tube now intuitively will this level ever get higher than that level no it's exactly the same here this potential can't get any higher than that potential because we can't transfer any more charge when they have the same potential energy so we need to figure out a way to get to hi

gher voltages and what I'd like to do is I'd like to introduce you to a pretty amazing apparatus here this is Lord Kev kelvin's water dropper Lord Kelvin demonstrated this here in the theater and I'm going to get it working hopefully um and what we're going to do is turn down the light so you can see it operate and then I'll explain it and so let's go ahead and get it started sometimes takes a little bit of all right okay it's started up now so if we could turn down the lights and just look to w

here my hand is for a little flash could we get the lights up just a little bit so I can check the meter there we go you see it back down now that it's flashing let's see if we can get another flash what we we get another one I think we will there you go do you all see that so what we're doing is I'll let this run for a little bit do you want to hook up the electroscope um what we are doing is we are creating charge from nothing so first off there's no current in these I decided to make this out

of copper pipe because I thought it looked nice but what's happening here is that we are actually inducing charge and I want to just go over to our little explain here remember I told you about charge separation here right so let's go over here as the water comes down these two circles are charged as they come down we polarize the water and then you notice what happens the Drop Falls right the Drop Falls so the drop who had an induced charge Falls away and as a result the water drops have charg

e what we do is we create positive charge in this one the positive charge repels the negative uh sorry the positive charge comes over here attracts the negative this goes down this becomes negative the negative comes over here it attracts positive and it's a feedback loop that goes back and forth on itself now Michael is that working for us yes all right excellent can we get the camera up on the screen it's working very well now so if you look as the voltage in creases they spread apart and then

there you go that's perfect that's great that's great lighting spread apart spread apart and then we get a spark that comes out there we're building up the charge until we get a spark across here that lights up the lights now I want to show you that indeed this is how it works so first off I have here a charge stick this is just like the fur and the PVC it just does it automatically for me so if you don't believe that water can be polarized do you see that right I'll do it for this side see how

it's attracted it's attracted for the same reason the balloon in the can was and so what I can do I'm going to turn this back on and going to zero that all out all right do you want to come and see if you can get the screen so what I'm going to try to do here is the water's going to flow through here and I'm just going to charge this up and just look at the number there you you see it going up all I've done I just have one Loop here that I charge it creates polarized water which creates charge

that flows down into here and that is how the Kelvin Thunder uh water dropper works all right thank you very much Michael now this was an interesting machine because because it uses induction and it um uses gravity to do the work the gravity is the one that's going back and uh dropping all the water drops and separating everything uh there's other machines out there how many of you have heard of a whims Hurst machine anyone a few of you well we have from the 1933 I believe Christmas lectures the

original whims Hurst machine that was used there [Music] and I'm going to explain this in a minute but I wanted just to First for you to see what it does go ahead and start it up Dan everyone see I think probably you can see with the camera pretty well there everyone see all right so the question is how does this generate charge most people think while there's something spinning inside it must be friction it is not it is induction all right Dan let's turn it off and of course being at the Royal

Institution we can't have a small wimhurst we must bring on a giant whims Hurst in order to explain this so if we can get the demo camera to come in tight to the um the disc here so if you'll notice in the whims Hurst we have a disc with metal foils on it uh let's see if you can maybe you guys see them right there there they are and we have the discs running here is my giant whims Hurst now I'm going to share with you the secret in how this is able to create much higher charge than we could bef

ore remember our two beakers of water we couldn't go any higher than our source what the whims Hurst is able to do is to actually generate higher voltages using induction and here's the key so if I were to place my metal pan above this charge the bottom and touch the top you could say oh well you're going to induce a charge we already saw you do that but remember that with my little wand when the two were together I had equal red and blue charge because the blue is made from the red I can never

have more so I never get more charge through induction when I just have one pen or the other take note however of in the whims Hurst there are two pieces of metal next to the one that my special electrode is over and I put it to you that these two will induce a charge on this and I want to demonstrate that to you what I'm going to do is I am going to charge up those two see if our wands will cooperate with us I'm going to charge up these two but not the center one so if I get any charge on this

it must be from these two and I'm going to take my charge stick charged up these two let's see if this will they're both red I think yes okay by the way the reason you sometimes see the blue flash is when I move it it gets an induced current in it so that's why it's there very slight spark you see my charge is now blue so what I've done is I've charged up these two and I've induced a little bit of charge on this so now what I'm going to do is charge up the middle one charge up these two those re

ally were charged up just got a spark I'm gonna get my one bit my one charge from the bottom plus a bit and another bit the one plus two bits then I'm going to rotate my wheel and I'm going to do that again here I'm going to do that again here to do that again here here now while I'm doing this on the top there's a partner of me on the other side charging up these bottom ones when we come back around full circle each one of these has one plus two bits because they are equivalent to the one I did

before so now I have one plus two bits one plus two bits one plus two bits so I'm immediately going to get one plus two bits on here plus a contribution plus a contribution I have more charge than I did originally and then I'm just going to circle back around and now I'm going to have even more charge and I will build up charge just like the Kelvin water drop did you notice I didn't start it it started by itself just a little bit of charge imbalance and then it has feedback that builds more and

more charge and so the secret of the whims is the fact that I get the charge from the one right beneath it plus the two next to it and that's how I get more charge every time I spin around because as I spin they come back and I can add the more charges from sides so that is the whims Hurst if we could take that off and I'd like to show you some classic demonstrations from the Royal Institution with this beautiful example of a whims Hurst machine and Michael if you can clear the buckets clear th

e buckets when you have a chance thank you great so we're going to start with the first one and I don't know if many of you are Hunters but we have here a hunter and this Hunter is going to be hunting some birds so and what we're going to do is we're going to charge this up and the birds are going to get charge and because they're the same charge they're going to fly apart so let's go ahead and turn it on let's see if we can get the birds to fly away [Music] all right so now the hunter is lookin

g for the birds can anyone help the hunter anyone help the hunter where should I go maybe in this direction excellent excellent he's looking around for some more Birds Fantastic comes back around and I'm just going to for this side over here to see oh he keeps on shooting the birds so you guys can see there and now he's just really going after all the birds that are there all right Dan thank you very much so that is a classic demonstration of Sparks uh in a fun way we are now going to do one mor

e demonstration that is the thunderous and Dan's going to pull it out and how many of you have heard of a lightning rod okay everyone how many of you believe that Benjamin Franklin actually took a key put it up on a kite and flew it no no I I don't think that's actually what happened but he was one of the first to realize the power of being able to guide electricity and charge realizing that the lightning we see are the same as the Sparks we see down here so what I have here is a lovely house an

d um we use the other nope Dan is right here here's what we need um I think you're missing a bit in the center though excellent so I know this piece my understanding is dates backs to at least the 1930s and I believe our head of Heritage said perhaps a little bit earlier or maybe even a lot earlier think it goes just in with friction you squeeze it like that okay so we're going to start with can we get the demo camera to come around you can already tell this is going to be fun I have to put on s

afety my PPE okay so what I'm going to do is I'm going to put on a lightning rod can you come around around and take a a video of the lightning rod the camera up there so here's my lightning rod and it's going to go right down to the ground and I'm going to just ground that there we go all right so now any lightning that comes in should go straight down the lightning rod and we should all be safe Dan would you start the whims Hurst okay we're building up okay we've got a little bit of lightning

there you see right it's not damaging no one in the house is dying no one is Catching Fire everyone's very happy so the lightning rod is a really really good thing all right so what we're going to do now is I'm just simply by the way in preparing for these demos that happens a whole lot there we go going to just adjust that now what I'm going to do is I'm going to take away my lightning rod and now my poor house is unprotected unprotected now I just want to refer you to what is on my eyeballs an

d let us see what happens in an unprotected house go ahead Dan the house is apparently just fine I'm not sure we can open up this house to see what happens inside okay we're he's going to try a bigger Spark [Applause] [Music] so I hope everyone will now have a lightning rod at their home um thank you Dan also for that Sage advice that we should get a little bit larger spark so that was the whims Hurst and what I want to do is I want to come back to um the vandergraph generator vandergraph was a

professor at MIT and he invented this generator in the late 1920s and it's become very popular and many people see it in large areas um let's just go ahead and start it everybody can see the Sparks everybody sees the Sparks there by the way our cameras hate the Sparks so if you see a blue screen that's what's happening okay so this is the Vander graph it's generating around 100,000 volts up until now now we were around 10,000 the Vander graph's getting us up to 100,000 volts and I'm just going t

o turn it off and I want to show you how it works so I'm going to take the top off and place it right over here okay I'm just going to turn it on so that everybody sees that there's a belt going up and down everybody see there there's a belt going up and down and so there's little people inside that are adding charge to that belt okay there's two ways to add charge one is with friction uh you can actually make the rollers a different material or you can actually use a high voltage source to do t

hat but when everyone explains the Vander graph what they do is they just explain the charge moving up the belt from here to here what they don't explain is the key innovation of what makes the Vander graph really special and I want to show that key aspect uh phenomena right here this is what Professor Vander graph figured out so I'm going to place on this a few thousand volts and let me turn this on okay so now I have a few thousand volts on this and what you want to pay attention to is this nu

mber um just want to make sure there we go so I've got a few thousand volts here hopefully when I touch it we can see the number go up don't touch it David it's a few thousand volts okay so this is just like the belt right I'm transferring the charge [Music] if you think this is getting old try practicing [Music] this okay we're up to 46 47 48 we're not really getting much above that makes sense right because of this okay so it doesn't seem like we could get to 100,000 volts if we're just puttin

g charge here and floating it up because it just could go as much high in potential as our little men down here could do however let's do something slightly different so what are we at now can you go back to this number just to see where we are okay I'm just going to get it back up [Music] to all right now is that 48 41 4 okay watch now it's only a few thousand volts all right we're going to have to charge that back up so let me zero that out I apologize okay I got to go back and do it I'm sorry

is our number not changing there we [Music] go it's kind of [Music] therapeutic okay there was stopping at around 41 this is not going where I want it to go I think the humidity's gotten to me we're at 50 we were never at 50 before were we of course I touched the side and then we go back down so you saw that we went above and what it is is that the vandor graph is actually a farad cage the potential inside of here is zero so in the outside we charge it up and we can't transfer into charge becau

se it's at the same potential but the inside all the charge cancels and we can continually flow charging there Mike could you come out with a bucket you have the bucket right there so that is equivalent if you remember we had our little demonstration here let's turn that down all right Mike has the bucket there going to lean this over and now imagine the potential in this one was Zero as it is inside of a faraday cage I could keep adding charge over and over and over and over again am I spilling

yep thanks and this is how the Vander graph works is by putting the charge in the center we are able to put much more charge in fact we could put an infinite amount of charge into this when we put it inside the charge goes to the outside and it's zero inside we can charge this up until this starts to break down the air and the shape that breaks down the air the least is a sphere and so that is why a vandergraph has a sphere but the key piece is the Faraday cage and you notice the little men who

put the charge on that goes to the top the charge goes inside of the Dome and that is what's key to how a Vander graph works so we've done up here all of these have been DC charged I want to start taking you into some other areas that we can look at so over here I have what is called a room cor coil so I should start back we're at the Royal Institution Michael Faraday discovered induction this is a replica ring so what he discovered is if you put a current through one side can we go let we got

it up there uh a change in current in one side will a change in current in the other and in this one he has an equal number of turns on these and this is the basic idea for what is known as a room cor machine and that is not the inventor but rather simply the uh instrument maker that made the best instruments this coil is the same as the original spark cap transmitter and what I did is I bought one of these and if we can go black on the top and I bought a second one and I took it apart to see ho

w it works worked and so what we have inside is we have one coil with maybe 200 turns and then we have another coil with maybe 2,000 turns and the way this works is we have a changing current in this coil and it gets multiplied by the difference in coil numbers so we have sort of a lever to get us higher and higher voltages from the second coil that's the first thing that this does the second thing is the voltage this produces is related to how fast we change the current So the faster we can cha

nge the current in this the higher voltage we will get on that and so our core is to do lots of currents High turns switch it fast and that is exactly what is inside of this machine and I'm just going to turn it on so that you can so that's what happens we're able to create very high voltages by using electromagnetic induction now this machine is a lot smaller than the Vander graph and it becomes a much more popular machine for us to generate high voltage with and many of you may say well this i

s all fine but I live in a normal household and we don't have Tesla coils and whims hursts and uh and these other however turns out that any of you who owns a petrol car indeed has a room Corf coil in it so I have here an induction coil and you may not recognize this because you uh haven't looked at your engine recently but you might recognize this as a spark plug right for a penol so this is what charges up the spark plug and what I do is I have a little oscillator here that's going to turn on

and off the current on and off the current and that oscillating current should generate for us a spark let's turn the lights back up and so in every petrol car you have your room cor coil and Vary much the same way there's two coils in here with a core that helps couple them together now we've done this and we've generated these high voltages and now what I want to do is I want to show you some applications of high voltage so I have over here this is the one that was shocking me earlier this is

just a smaller version of that one and it generates around 30 to 40,000 volts and um Dan you have an incent yeah thanks so what I'm going to do is I'm going to turn it on and what I have here can we get the demo camera to come in close very close so what I have is a sharp point and then these cylinders are not nearly as sharp and what's going to happen is near the sharp point I have a really high electric field and it is going to rip the electrons off the air molecules and now the big heavy ion

the ion is the molecule without the electron it is going to be accelerated through the electric field from the tip to the cylinders now this is big and heavy if I'm creating the electric field the force that moves this has an equal reaction to me so it pushes on me in the opposite direction so we're going to push air this way it's going to push back a little bit on this but let's just see how much air flow we can generate from these ions flowing from the sharp to the um uh rounded okay it's a lo

t of air there we go we get that you see that that is all caused by the electric field making ions and then accelerating them towards the uh less sharp coils so this is known as an ion Thruster and if we can have an ion Thruster do you think we can meet an ion spacecraft or an ion craft yes so let's see if we can make one of those I have here an ion lifter if you could zoom out we could take a look at our nice triangle here and what I'm going to do is the same if you I guess close in a little bi

t if you can see there's a sharp wire at the top and that sharp wire is the same as the nail and then the bottom side is smoother and so those ions get accelerated remember they get torn apart at the sharp place and they always accelerate to the smooth place they don't get torn apart at that smooth place so I'm going to turn this up and hopefully we can see if we can get something to fly Dan if you want to take the incense you see the air going through going directly down there so we're able to

use that electric field to accelerate ions to allow us to cheve actual flight it's pretty cool excellent so this are some of the things we can do with these room Corf machines and here I created some ions I want to talk now about something called plasma plasma is simply a collection of charged particles they could be ions or they could be electrons and we can do all kinds of interesting things with plasmas and I want to show you a couple of these in these next three demonstrations so first off w

hat should you never put in the microwave grapes yes that's correct so I have here the grape just going to cut it in half so I've just cut a grape in half now if you can take a look with the camera let's just set it up all right so what is happening why did the grape Catch Fire it's like a tuning fork so the microwave runs at 2.4 GHz which very fast frequency but it turns out the wavelength inside of a grape is resonance if the grapes were too big the grapes would be too big to have resonance li

ke a tuning fork so what we're trying to do is tune our fruit to the exact Resonance of her microwave so that's a pretty cool demo but you probably for those on the side you may have seen a little bit in it's kind of annoying to look through here so Dan do you have any ideas on how we might be to look better into the microwave what are you going to do Dan hole in the back hole in the back only at the Royal Institution would we drill a hole in the back of your microwave um please don't do this at

home we are not not responsible and there you go it's a little bit difficult to drill the hole there then I'm going to give you my phone and I think you know what to do so what we're going to do is I'm going to light the other thing you should never do is put fire in the microwave so I'm going to light a candle and um you're going to want to see if we can get a picture on the phone of what's there to put that up there so I'm going to light my candle now why am I lighting a candle because a flam

e actually ionizes the air so we're going to get some ions from this candle and my hope is that maybe the microwave can achieve a resonance that causes a plasma to form and if you're like what's a plasma look like if we're successful you'll [Music] know going to get it again going to let that have a little bit of air but there we saw a plasma generated inside of the microwave I will give it one more shot to see if we can get a little bit longer lasting plasma by the way part of the problem is th

e tealight um wax doesn't like the microwave I haven't figured out yet why all right there we go all right we saw it the one time we could be at this for a while for the microwave but that's one fun way to generate some plasma uh thanks Dan perfect go ahead put it on [Laughter] [Music] [Music] top [Music] now there are some other interesting ways with the room Corf machine that we can generate some plasma so up until now when we talked about the ion lifters we were talking about uh electric fiel

ds and air ripping apart molecules what happens if we remove all of the air if we remove all of the air then there's no ions the electrons are now free to flow from the two connections that's exactly how a vacuum tube Works caade tube works and so what we're going to do with the room cor machine here is I'm going to turn it on and we are going to take the vacuum out of this and initially we're going to see a spark right here and that spark is going to die away when a plasma stream of electrons s

tarts to form over here so I'm going to let's keep it black until this forms cuz I think it uh disturbs the camera go ahead thank you you see it [Music] forming how's that so this is a stream of electrons going between the top ball and the bottom and someone asked me once well are the electrons going from the bottom to the top or from the top to the bottom my answer is I don't know uh when JJ Thompson discovered the electron this is indeed how he did it was to look at the fact that the electron

is a particle there is no particle of positive charge so he could actually look at the physical transfer of electrons now this is super cool but it probably does not surprise you turn off the back that um in the late 1800s it was very popular in towns such as London at the Royal Institution to do as amazing a demonstration as you could and there was one particular demonstration that was very famous for using the rorf coil and that was called gasio fountain sorry my French is horrible and what we

're going to do is we're going to take this out and now I'm requiring ired to tell you that there's two precious items in here they are not from the archive however this is just a really cool box so I'm going to pull this out so this is simply a glass goblet it is green because it's impregnated with uranium that's how they used to make green glasses and there's just a bit bit of tin foil in the top so now I'm going to place this here we're going to do the exact same and the ball is not really to

uching the tin foil inside that's not so critical and now we are going to try this demonstration one more [Music] time you may want to video this if you do make sure your light is off your torch just want to make sure our seal is good could I get a little bit of the house lights I just want to check our pressure we are going down okay we're going to turn it off and give it another quick try here turn that off thank you I think our vacuum may not be down quite enough to do this start it again [Mu

sic] please there we go it was worth I think the weit the charge is going into the glass outside and back down and it is a fountain all around the glass and you have to admit that would be very impressive in this exact theater in the late 1800s and this is one of the really pretty things we can do with plasmas now there's one more plasma that I would like to um share with you and it is a very special plasma so I have here an apparatus that my students made and it um contains an oscillator and an

oscillator is just like a swing and we're going to circulate a current by the way this is just a wire I made it out of very thin tubing because it was nice and rigid so we're going to oscillate a current in here and if you remember you remember from physics class the current will have a magnetic field that wraps around so we're going to have a magnetic field that circulates around here now that in itself might not be too exciting so I want to add one more piece and it is once again in our speci

al box so this is a bespoke globe 2 L filled with Zenon and nothing else and what I'm going to do is place this right there in the center okay now I'm going to touch it there's nothing to be seen J take the lights down real quick there's nothing there let's bring the lights up a little bit so can add a little power okay nothing there nothing coming on so what I want to do is I want to indu if you remember induction was what we learned earlier I want to induce some charge near the edge and hopefu

lly that charge will then start to circulate in the magnetic field and maybe we can get some glow or maybe some other very interesting phenomena and to get that what I'm going to do is take my stick as I did before and let's see if hopefully there's not enough moisture let's take the lights down so now what we have is we've created an imbalance of charge that's now circulating around and I can come in and touch and create some amazing things this is a plasma toroid and it forms and becomes a ste

ady state inside of the globe when you saw those little streamers those little white streamers when those streamers come back on themselves I'm going to turn it down and see if we can't get the streamers back it's going to float back to the top and so if I can get one of these to Circle back on itself it'll form a complete circle circuit and then that will suck all of the charge in to form the plasma toroid we just saw and of course last time it happened quickly and there we are it is thank [Mus

ic] it is completely self- sustained inside and I just lower the power and you can see it slowly rise up in case you didn't believe it's actually floating inside of the globe and so this is gaso Fountain for today for 2023 is right here with the plasma toroid thank you can we have the lights back up thank you Michael it was kind of you to loan that for us and um so now I want to talk about our final instrument you've probably already seen it here how many of you recognize this guy right here thi

s is a Tesla coil and I'll have to ask Charlotte here do you remember what year that Tesla lectured here by any chance 1890 1890 Tesla stood right here and did a demonstration of his Tesla coil now what is different about a Tesla coil than this room cor coil is how many of you pushed someone on swing yeah everyone okay you maybe even have swung yourself and kicked your legs and got you up did you have to lift the person all the way to their maximum height no you just add a little bit of energy a

nd the swing starts to resonate what is different about a Tesla coil these Tesla coils is we have the same inductor that we had on a room cor machine however now we have a capacitor it doesn't look like a capacitor but when you're 100,000 volts or a million volts this is a capacitor and this is going to resonate with the coil to produce extremely high voltages you can't see it very well do you want to come in close might help you to see there's a little bit of a you can see some windings here pe

rhaps that that is the initial coil and you can see this is about five turns and this is about I don't know 800 turns a th turns my student has wound many many of these so let's get uh and take a look at what this sounds like okay so just for safety reasons want to check everything this is a point if you have any issues with ozone should be fine but we will be generating a lot of ozone with this and the other um final demonstrations so most people think that maybe a Tesla coil is continuous but

it really just comes on for 20 microseconds few millions of a second and then turns [Music] off all right now it's just showing off so why do we hear it we hear it because it's ripping apart uh air molecules and that that's creating a vibration in the air which our ears can hear so it's those ions moving in the electric field that causes the noise and one of the really fun things that we can do with um Tesla coils is they actually can play music let's see if we can get our Tesla coil here to pla

y us a nice song okay if we can hold with the lights I just hit the wrong button sorry [Music] [Music] all right let's give the Tesla a round of applause so now this is an amazing little Tesla CL but like the whims Hurst machine this this really isn't big enough for the Royal Institution so I brought all the way from America my own Tesla coil which is so dangerous that they required that I put it inside the Faraday cage from the 1933 Christmas lecture and here we [Music] [Music] are all [Music]

now what's great if we could bring the house lights up this one can also play music [Music] [Music] n [Music] [Applause] now if both coils can play music do you think we could ask them to do a duet would you be willing yes all right [Music] e [Music] [Applause] now if I recall I did promise you a million volts do you recall how big the spark needs to be a meter in the US it only has to be a yard it's lower voltage in the US there all right um Dan could we take the Tesla coil out yes we are and D

an if you could place that approximately a meter away and maybe bend the tip down a little bit there we go if you're all wondering this is a fiber optic cable to keep me alive so I think we're just going to uh if you can lock this up Mike we will get this tested away I think that's good so let's just test it out a little bit see what happens [Music] now I want to pause here I want you to look at the two fluorescent lights and notice that the one on top the Faraday cage lights up and the one insi

de does not let's take the lights down [Music] again can you see that excellent now if we take the lights back up we were having discussion with the the demo team and the question came up was is it safe to go inside of a faraday cage and my answer was in theory yes and they said I should show it in practice so uh for safety reasons I need to unplug myself lest I be a Tesla coil inside of you got it Mike all right wish me luck if I don't see you thank you very much for coming we take your PIN it'

s going to be fun all right uh you promised one meter yes hold on a second you we can turn down the lights so I can do a prayer please more power [Music] [Applause] W if he still has the power of speech um we've got a few thank yous to do before we thank Professor rickets again my name is Daniel Glazer I'm the director of science engagement here um and before I give context to where's the Faraday Box before I give context uh to what David has shown you today I think he's got a few thank yous tha

t he wants to give and so I wonder if I can ask the demo team uh that's Dan Mike Isa Tom Charlotte to come out uh because uh without these guys uh come on Charlotte you have to move down none of these would have been possible [Applause] here so why don't we get uh [Applause] [Music] [Applause] Dan Dan I have something in the Box for you come take a look I'm getting in the boook you're getting in this box that is going to be the most amazing demo I've ever seen um thank you there you are a little

inscription for you I you need the microphone oh you want me to read it okay two the ri demo team the most amazing people at the most amazing place keep inspiring us all Professor rickets 24th of the 6 23 you even did the dat the right way well done thank you thank you very much unbelievably kind so much everybody so we do need we do need a little bit of history for this we got an email a couple of years ago Charlotte and I from this guy in Harvard who was a fan of Michael Faraday's and althoug

h he was orig electrical engineer his day job is doing Innovation but he decided to come here and do a bunch of experiments uh to lead uh to the end of the journey which culminated in the electric motor and if you've been to the museum downstairs you'll see the world's first electric motor was made by Michael Faraday and we thought that would be a fun thing to do and David came towards the end of uh the coid time and over the last couple of years he's demonstrated the most extraordinary generosi

ty to the RI not least because he's given a bunch of sweatshirts and lab coats with his own initials uh well the first two letters of his name uh to the ri but also he's developed um again at his own uh instigation with his own funding many of the things that you've seen here which I think is fair to say David you will not see anywhere else in the world most of these demos do not exist you will not there is not the cup and the toroid you will see nowhere else I don't think the Cup's been shown f

or 50 or 100 years so there are things that you'll see here which are practiced and easy and there are things that are at the very edge both of Technology safety and practical ity and this evening you've been taken to the very edge of that but in a way which as David has said since 1799 has been happening in this theater and a lot of the discoveries and the technology that he's shown are from this very Place uh the whims machine for example you can see when you go outside is in the uh painting u

h at the back there which is normally in the display case but what he's done for us and I think for us as individuals for us as a community and for the people in the demo team is to take stuff out of their cases and put them to use which is like we like them to be at the institution so with that historical context and at the very stting edge of of Science and safety uh we've had an extraordinary evening please join me once again in thanking your lecture this evening Dr David [Applause] RS