Faraday Cage

so today we are gonna learn about electrostatic shielding and Faraday cages and why it's not such a bad thing if you're in a lightning storm as long as you're inside a car and I don't want to do that with me so we're gonna do with then June here we have Benjamin Franklin wearing a nice little Hawaiian hula skirt made of tinsel and he is about to be in a thunderstorm we are going to make our thunderstorm with our Van de Graaff generator you can think of the belt in the Van de Graaff generator going around like this as analogous to the air circulation underneath the Thunder head as the Thunder head builds up and then you can think of this up here is the analog of the cloud so soon as i ungrounded art charging up and you see mr. franklin they're getting a little bit uncomfortable you see his hula skirt streaming out behind him as he is in right now in quite a large electric field and as you can get a sense there he's not so happy at this point maybe I'll turn it up even higher there you see well I've got a lightning bolt going to my grounding rod and as you can look at what's happening to Benjamin as the lightning bolt hits the grounding rod there you go Benjamin is not happy so now what we're gonna do is we are going to have the same thunderstorm the same electric field but we are gonna put Benjamin in a Faraday cage so to put him in the cage I'm going to start by turning this off and we'll ground him and here's my Faraday cage right here I'm gonna put Benjamin in the cage there we go okay Benjamin's gonna be in the same spot that he was before same tinsel skirt that he has but had before but this time he is in a cage like for example if you're in a thunderstorm but you are safely in a car so let's see whether it is indeed safe and here we go let's turn on the Thunder or the Lightning rather let's turn on the lightning now if you look you can see that there's lightning hitting the cage there is that lightning bolt going from the vandegraaff right to the cage here and you can see that the cage has a very considerable electric field on it by looking at the tinsel over here on the far side which is streaming out behind it just like the tinsel on Benjamin was before but now I'll look inside at Benjamin in there and I have to be careful not to touch the cage but now look inside at Benjamin in there and his tinsel is completely motionless Benjamin is completely comfortable in there calm at rest while the lightning storm rages around him literally around him and I just got me if I touch that I get shocked ok that's what that's what I just got shocked but Benjamin is completely safe this is the phenomenon of electrostatic shielding and this kind of a cage is often called a Faraday cage and will now turn the Lightning off

Channel: MITx Videos

Views: 223,193

Rating: 4.9059892 out of 5

Keywords: Faraday Cages, faraday, MIT, MITx, Massachusetts Institute of Technology, Krishna Rajagopal, physics, electricity, magnetism, lightning, MOOCs, free online courses, free college courses, online courses, Van de Graff generator, Ben Franklin, tinsel, tinsel hula skirt

Id: QU0fLnucE6A

Length: 3min 14sec (194 seconds)

Published: Tue Oct 09 2018