Enjoyable science video by Veritasium. I'm just glad I got the question right. Edit: https://www.reddit.com/r/Veritasium/comments/qyn2om/why_15_minutes_might_be_a_better_trick_response/ This thread shows how the initial premise works, though the thread points out the bulb is so dim that only a tool designed to see light could be calibrated to see the bulb turn on. Website that might explain better than the video. http://amasci.com/elect/poynt/poynt.html This video below explains how flow still works when the wires are cut. Another video that is more clear on how the flow of energy works.
Nice and all, but no information can travel faster than the speed of light in the medium it is being transmitted in. It will take a year at least for the circuit to even realize it was completed. How it will behave then could be as he said, but until then he cant. It would violate fundamental laws of the universe to transmit information of wire being unbroken instantly. I like his videos usually, but this is just false.
Looking into this video a little more, I can see why the video is misleading, but there is something to be learned. Electrons don't actually go through the wires from the power source to the destination. They almost don't move at all. Energy flows through the air, not the wire. This picture shows how the initial premise would work. Light bulb is 1 meter away from the power source with 1/2 light year electric cables with no resistance on both sides. 1. There is a loop between power source and light bulb. 2. The loop is cut at both ends. 3. The power source induces a current on one side, making the light bulb turn on for a brief moment on the other side. Probably only works in theory. Real life doesn't have the ideal conditions to make this work. Also, laying down the wires/circuit is the one that is already carrying this information at sub light speeds. Measuring this at any point shouldn't violate causality.
Im pretty sure that's not really true either. Electron movement, yeah, but not field thingy. Maybe on tiny scales, but once you get into field theory and realize how much energy we transmit over continental distances it falls apart. Fields that would require would create massive losses in the network. Also, why would high voltage jump in such case?
The electro-magnetic fields exist around the wires, so it's cheaper to lay down wires instead of generating a huge electro-magnetic field around a big magnet. High voltage jumps across the air to metal because the difference between charges is enough to overcome air resistance. Energy flows through the air around the wire, since there needs to be a source of EMF. Wires generate the field needed for energy to flow from power source to destination.
Yes, but it is tiny. And in wire with no resistance at all, you don't get magnetic field. Also, it would still need to propagate trough the whole length of the wire.
I apologize. It seems you're talking about a perfect conductor having no electro-magnetic field, which I assumed would work. Upon further research, the electric field would reach equilibrium almost instantly with a perfect conductor, so no current would flow. I agree that the energy would have to travel along the whole length of the wire, but only along the electro-magnetic field.
Doesn't meisner effect delete magnetic field inside the superconductor? 0 resistance should mean no losses in the circuit, else you would get infinitely large magnetic field that would just eat all the power. I may be wrong about that one, I admit. This wasn't something I really studied. That said, The information of circuit being completed should travel trough wire, not outside it. There is no reason for the circuit to consider another side to be part of itself until signal gets there. I doubt magnetic field would form between them before that. If only because it's just piece of wire without any voltage until your signal arrives there.
A superconductor is technically not a perfect conductor due to a perfect conductor keeping it's magnetic flux, while a superconductor expels its magnetic flux, but you're right about the Meissner effect. Information is travelling along the wire and also outwards from the power source. The light bulb turns "on" if we consider a slight change in voltage from 0 volts to a small amount of microvolts. In practice, the time taken for the light bulb to get bright enough for the human eye to notice is a few minutes because most of the energy is still travelling alongside the wire. Simply, the bulb and power source can be thought as antennas that receive and send signals, even though there are wires connecting them. The signal sent directly from the power source to the bulb is very weak, while the wires carrying the stronger signals will take the long trip. The video seems like a differing viewpoint of a physicist versus an engineer. Sorry for editing my comment so much, but I just want to make sure what I'm writing is factual. Hopefully there's a follow-up video. Found something that might explain better. http://amasci.com/elect/poynt/poynt.html This video might explain it better.