AlphaPhoenix - 2021-12-17
I constructed the Veritasium electricity thought experiment in real life to test the result. If you were watching my community posts a month ago, the day that Derek over on Veritasium posted his video about electricity misconceptions, you saw me obsess over that problem a bit too much and immediately use it as the excuse I've been looking for for years to own my own oscilloscope. Instead of two light-seconds of wire, I used about 3 light-microseconds of wire, but it was PLENTY to resolve exactly what is happening in this circuit. I hope you enjoy the analysis! Thanks to Derek at Veritasium for his blessing to make a real-world version of his gedanken experiment. If you haven't seen his video yet, you might want to go watch that for context, and I also highly recommend ElectroBOOM's video on the topic and EEVBlog's video on the topic. Electroboom's video has some simulated scope traces extremely close to what I saw IRL, and a REALLY fantastic animation (8:27) of him waving an electron around in his hand, shedding magnetic fields as it moves (Even though I ignore magnetic fields in this video - I'm trying to think of a test to find out if they matter). Veritasium https://youtu.be/bHIhgxav9LY ElectroBOOM https://youtu.be/iph500cPK28 EEVBlog https://youtu.be/VQsoG45Y_00 Music Credits, etc.: I Dunno by grapes is licensed under a Creative Commons Attribution license (https://creativecommons.org/licenses/by/3.0/) http://ccmixter.org/files/grapes/16626
Very good test. It is always great to see what happens in reality! Thanks you.
Impedance matching would raise your output voltage. But also in your setup, I would be very worried about the capacitance the probes add between the lines. Remember the stray capacitance between the wires is VERY small, likely much smaller than the capacitance at the probe output. Probes have capacitance to ground and with probes on the switch and load side, you are basically coupling the switch to the load side with extra probe capacitance. I say place probes ONLY on the load side (you still see the steps), make sure your probe is on x10 for smallest capacitance, and maybe use special high frequency probes.
Other than that, the only thing that might not have a significant effect is the capacitive coupling through the earth which makes for a slight output voltage difference. Nothing huge though.
One more note, knowing your load resistance and the voltage of the first step, you can calculate the line characteristic impedance, and match your load to it, or pick a higher load to see a much larger voltage step at the output.
GOOD LUCK with your future tests.
Ah yes all of these words make sense to me. lol. I’m loving that Derek sparked so much enthusiasm for science with that video, even if proved right or wrong, this thought experiment is wonderful to uncover through all of you.
Mehdi, you forgot to mention the step when you get shocked :P
Are you going to make a video on this?
So interested to read this. It also seemed to me that the capacitative coupling was high for two wires a meter apart. The probe capacitance would explain it. Cool.
@Hippo T He did, a week ago
Current bouncing back and forth causes havoc in electrical fired fireworks unless a firing system has gates built into the circuit. Electric blasting circuits can also have this problem especially when extraneous current is starts to enter the circuit. It's a deep subject that very few truly understand. Maybe you can do a video to prove if a shunted blasting circuit is safer Vs an unshunted one. Again it's a massivly deep bunnyhole of argument.
This reminds me of a true story about an electricity supply company's underground cable division many decades ago. They had an experimental machine in the back of a small truck that could tell them at what distance away their buried power line has a break and where to dig into the ground. They didn't use the machine very often but when they did use it always told them the distance to dig, they dig there, they wouldn't find the break there, then have to dig along either direction expose more cable to find break. After a while they realised the break is always exactly 6 feet away from where the machine says. Then they realised that for all of the years they had been using it they had not been including the length of the hook up cables in between the machine and buried power line.
The machine you are referring to is called a Time Domain Reflectometer (TDR) and is used extensively today. Not accounting for your launch cable is a rookie mistake 😊. The way it works is that electricity will travel at a fraction of the speed of light in a medium depending on the construction (the makeup of the copper conductor) of the cable. The manufacturer of the cable will provide the type of cable that you can then enter into the TDR and “shoot” it to find the distance to the damage, or end of the cable. The signal sent out from the TDR will bounce off the damage and reflect back to the TDR. So if the machine knows the makeup of the cable it can determine the length very precisely.
I use to use a TDR on heavy jets. Works great. But few understood how or when to use it.
Time delay reflectometer? TDR
Time delay reflectometer would make more sense, but it is time domain reflectometer. https://en.m.wikipedia.org/wiki/Time-domain_reflectometer
@owakulukem Got it. Thanks. “Delay” does make a lot more sense but of it is call Domain, then we will call it domain.
At least someone was able to explain what Derek from Veritasium was trying to say. Thank you AlphaPhoenix!
Hey Eric, great video. A question though. Would the "almost immediate 0.2v in your experiment" ripple come a little later if the wires were in a large circle rather than running parallel to one another? Surely the photon influence would take longer to affect the lightbulb as the wires leaving the battery would be a lot further away from the lightbulb?
You have an amazing ability to simplify the most complicated scientific conclusions into relatable examples that almost anyone can understand and make it fun and fascinating while you do it. Kudos
Best video out there to explain this! A real experiment does so much more than all the hand waving that goes on trying to explain a phenomenon. So good, thank you for this.
Have u seen electroboom's video on this topic ,concise and straight to the point from engineering perspective.
cringe...
passive aggressive cringe
ActionLab lets gooo
@GAME OVER yeah and he goes into more detail too, it was a great video
Derek's video put me into several hours of thought. I did not think that capacitive coupling could have a measurable effect at that distance, but was very pleased to be shown that I was wrong. Kudos to you for an excellent and well presented explanation of "Derek's Conundrum", as well as the experimental evidence of it's truth.
btw, this is a very good production, with a lot of effort, and excellent explanations. You would probably make an excellent professor or other type of educational figure.
Absolutely great! Love the editions using animations on the video itself. What editing software do you use ? Another question, how much does this kind of oscilloscope normally costs ?
I am a strong visual thinker who likes logic puzzles but severely struggles with comprehending mathematical concepts because they are so nebulous to my inner eye, and I LOVE this video!!! There is still a lot I don't really understand lol, but at least my overall comprehension of this topic has noticeably improved, even after just one viewing 😁. Thank you so much for all the effort, care, enthusiasm, and 'positivity' you put into making and editing this video of the experiment. I am looking forward to part 2 next. Round of applause and standing ovation! 🙏👏
I haven't seen part 2. This is a wonderful start to exploring capacitance and inductance. There is so much more to see if you continue to make variables. Do some reading up on capacitance and inductance. Also, look into the Q factor when power companies have very long runs of high voltage at 60 Hz power transmission. Keep up the good work. Good luck. Don't loose interest.
Definitely the best “response” videos of the Veritasium vid yet. I learned a lot and wow, what a wealth of info you are sir. I can’t wait for the next one
Eĺectroboom's answer was very good too , electricians/electronicians i guess
Background in physics and materials science (emphasis on semiconductors 😁)
All my electronics projects are very hobby-level, but hey, now I own a scope, so maybe I’ll finish that Theremin I tried to build in undergrad and finally satisfy my curiosity for oscillators xD
Agreed, thank you
I also agree! Great video, great experiment! Warm greetings from germany :)
@AlphaPhoenix that background is what makes your video on this so much better than everyone else's. This is a situation where the nanoscale mechanics DO matter, and those who don't study semiconductor physics are taught that they almost never matter. Well, that and they aren't ever really taught at all, because the math involved in semiconductor physics is complicated! (and fun; the class I took on them was my favorite in all of my time in college :))
It's called "velocity factor", and radio buffs take it into note while designing antenna systems-co phasing harnesses, for example.
Yep. In open wire, it's about 0.95
Ay was looking for a HAM related comment!
Always good comments to read on good videos! ty :)
Velocifactor?🦖
velocity factor in respect to the speed of light. thus .95 x speed of light.
You can hear your passion gotta love it. Makes you a great teacher
What an incredible video! I learned so much! Thank you for taking so much time and effort to create something so educational.
Extraordinary, finally a real-world experiment, not just the theory. I like what you have demonstrated and explained so far! I was hoping that you'd show what you showed (including the bounce), great!
first time seeing this channel, and I really like the concept of the name. The Intro was very simple but kinda hyped me. A Phoenix that is guaranteed to resurrect in that sense, nice wordplay with Alpha, Plan A and going up in flames. Really sick idea dude.
If the resistor is not a light builb, you are just not driving it hard enough.
looool 😅
Everything is a lightbulb with enough current at short enough timeframes.
X'D
Cigarette lighter
Everything's a lightbulb if you're brave enough
Excellent graphics and animation, they may not be flashy but definitely get the point across. Thank you.
Love the channel! I would love to see you do a tutorial on using an Oscilloscope I have not found anything even remotely as comprehensive as you explained!
Nice! It would be interesting to try with a Led (changing the set-up in such a way that is enough power )and film it to watch how it turns on in real-time.
Having watched this video for 20 minutes, this is what I've learned: this guy is very smart, and I believe him!!
I appreciate you making this video. I watched Derek's video when it first came out and was intrigued as well. I do think you should have insulated the space between the switch and lightbulb though, in order to rule out travel through air.
Edit: Paused at like ~16mins when you started explaining basic current theory. Continued watching to see you covered it. Well done.
Phenomenal breakdown. I taught high school physics for many years which doesn't mean I'm an expert in physics, but I do feel qualified to evaluate your teaching skills which are through the roof. Can't wait for part 2.
agreed. i want to see the same exact setup but with a Faraday cage to block the EM field between the battery half and the light bulb half.
The idea that excites me the most is the idea that he’s just doing what he loves, he has a passion for creating content and he is VERY good at it, imagine if he released some sort of online class.
Glad you liked it! It was such a frustrating question I HAD to set it up. I ordered the scope less than 6 hours after watching Derek’s video…
@AlphaPhoenix - You know, the largest discoveries usually stems from, "hmh, that's odd...". This question/example had me frustrated as well, but I don't have the equipment to do what you did. Really appreciate both you taking time, and your teaching skills!
And to think I thought you were crazy when you made your laser video... Thank you very much, Brian! <3
Yeah, this guy would make a phenomenal teacher. 🥳
Has been WAY more enlightening than confusing. After the second time I watched... Great stuff. SOOOO well explained. Thank you.
Very well thought out and explained experiment. Subbed! I'm just a lowly COE (computer engineering major), but I do recall a lot of my hardware roots from this video! lol
I like how he explains things. I wish he'd explain how our bodies attract static electricity to the point where we shock other people or get a spark when touching a metal surface. It happens to me at work in the winter all the time.
he just did......
Hi. This is absolutely THE best explanation of what is going on in an electrical circuit that I've ever heard. Thank you very much - I appreciate it.
I, logically asked myself what would happen if the circuit was made into a huge circular layout (so as to minimise inductive effects), and I see that you allude to that very near the end.
Hopefully part 2 (which I'm off to try and find) will cover this.
Thank you again, and btw, I have subscribed on the strength of this video.
Regards Mark in the UK
Wow!!! I would never have guessed about that immediate first little blip of energy!! Well explained!!! Great video!!!
In four years as a physics student I never took a course as compelling as your 22 minute video. This is the best thing I have seen on Youtube and the first time I've looked for a donation address. Thank you.
I really don’t know why I keep watching videos like this when I have no idea what the hell is going on the entire time but I’m entertained
This has to be the best example of the scientific method I've seen on YouTube in a long time, maybe ever. Great work. This is the first video of yours I've seen and you earned an instant subscriber.
Great experiment and very good explanation!
Great video! Glad you set Veritassium straight. His wire speed of light video was more click bait than anything. I also really liked that you redid the experiment with the wires cut. Great job!
Good video, I have just one thought. If you cooled the wire to absolute zero, what changes would it have on the measurements?
This measurement technique is actually used to locate broken electricity lines in the ground. The exact position of the failure can be measured by the delay time of the open circuit.
That's amazing.
Are you talking about a time domain reflectometer (TDR)?
Same with fiber optic cables as well I believe, a break causes a reflection that can be measured.
I was about to ask this, thanks.
I believe standard ethernet ports still do this. I know for a while you could see in the BIOS of some systems, whether a cable was plugged in and its length, even if nothing was plugged into the other end. I don't know if that feature is still around or not.
I ❤ the explanation of the scope! Very nice video new sub 🎉
Hi Derek, I vote for inductance as the source of the immediate current flow as there is a very rapid change in current flow when the switch is tripped. I suggest setting up the experiment with the "light bulb" 250m from the battery and having the switch in various locations. I think closing the switch results in a big change in the electric field around the switch producing an electromagnetic pulse that induces current flow in the "light bulb".
I think this is essentially the explanation given in the original video
Thanks! I finally got that with your elegant explanation of electrons interaction! 😁
Reminds me of when we went into excruciating detail about transmission lines in my EE degree course many years ago! This was probably worked out first by Lord Kelvin in 1860 or so in connection with transatlantic telegraph cables.
first time I've actually put some thought into this. So with the info you've given us, I got curious about why measuring it this way is the best way to measure it. i mean yes, you're measuring 2 things from from one point to the next. In a circuit such as this though, it's like you're measuring 2 relay racers times between their starting points. relay racers start to pace before a baton is handed off. So it just makes things a bit more complicated between what electrons are dormant and ready to move and what aren't. if you created 2 circuits. one with a laser (high mw) diode followed by a switch then battery then distance of wire to a resistor then to the back of the laser. a second circuit with a thermal diode used as a switch and the circuit is fully together but not completed because of the diode not being activated for completion. using a duplicate circuit of each to line everything up. then final test on the main ones. measure for when the resistance changes in each circuit. as well as the measuring voltage change after each circuits switch/diode. then comparing the exact time at which each circuit voltage change had started, gives you an exact measurement of when one circuits electricity has started, how quickly it moved the light to the other for it to start, and also how quickly that one started. if you're worried about heat transfer then use a photodiode instead of thermal. i only said thermal because lasers do disperse light as they travel. but focusing on the distance of the laser, the circuit voltage and resistance, i think you've managed to be able to find a mean between the two circuits values distance the electricity traveled, the time it took, the distance the light traveled, the time it took and can solve for velocity of both
i'm probably way off.. but i think two separate circuits is far easy so you can use the light in the middle to activate the other
Ah so that's what an "electric field" looks like, weird my physics teacher didn't mention it's full of grass and a fence
No thats the normal field. If you zoom in far enough you can see tiny Daft Punk concerts on the wires. That's the electric field
And if you’ve ever seen a romance movie where two people run down a field to hug and kiss that’s a magnetic field
pasture for electric sheep?
If you want to be technical, the electric field is everywhere, so you're never really wrong.
I think you'll find he is out standing in his field
Incredibly beautiful explanation, thank you ! I subbed to your channel, now I’m hungry for more 😅. Keep up the good work !
The negative swing is also a great example of the whole signal on the other end of the inductor/capacitor being the derivative of the voltage. When the voltage start going down it goes negative.
great work and excellent explanations, subscribed!
Man! Thanks for making this explanation - this is exactly how I understood Derek's results as electrical engineer (graduated 20 years ago but working as IT engineer). In my opinion Derek a bit missinterpreted his results. BTW did you try to check dependency of the initial current on the distance between the wires? I think it could help us conmfirm that the initial current comes from capacitnace/induction.
Physics exepriments like this one are always fun and frustrating to me in equal measure. I'm what people call "gifted" because I meet some arbitrary IQ threshold. My strength is spatial reasoning, but I have trouble with numbers. Specifically, doing actual calculations with them. When I see an experiment like this, I can spot or deduce the inner logic very quickly, and I can usually say if we have the necessary variables to calculate something. But as soon as I try to actually calculate anything, my brain just says "nah, let someone else do that, you've already seen the interesting part". It made math really frustrating in school, because there it focuses almost exclusively on the actual numbers and less how any calculations fit into real life situations :)
This video is PHENOMINAL compared to every other explanation I have seen. I absolutely cannot wait until part 2 as alternate configurations of the loop have been bouncing around my head for the last month. (especially the spread out one!)
Wholeheartedly agree with Goodgu - everyone else seems to have completely missed the point. Even the talk of inductance/capacitance seems to miss the point really, but it is good to see the actual effect quantified after so many people relied on it for their whole explanation. The question is ENTIRELY about the whether the energy is carried by the Poynting field, or by the moving electrons.
totally agree. The oscilloscope cleared it up so much. Especially with the cut wire.
I believe that this plus electroboom's video are the perfect combo
@Paul Wright We already know there are charge effects that will occur over distance and the strength of those effects are inversely proportional to the distance from the charge, in this case the electron. You can mathematically describe what is happening but it doesn't change the reality of how it works. The energy is both In the wire and Outside of the wire. The fact that the electrons are strongly coupled to the conductor and move inside of the conductor (sometime closer to the surface depending on the nature of the current) means that the majority of the energy carried must be proximal to the electron. That is why the conductor's are carrying most of the power, and that is why the Original Video that Veritasium presented is highly misleading because it suggests that (Paraphrase) "it's all about what's happening outside of the wire, not what's happening inside". And that is simply incorrect.
I do wish Veritasium had posted his own video walking back his claims when it became quite evident (even by his own words) that the light would not turn "ON" but instead was only dimly lit. (I actually doubt a real light would actually be on by any reasonable stretch of the definition, but I would accept 80% of nominal as on or even many other versions of on. But a slight glow... no)
I really appreciate this actual demonstration.
Again, you can't run this kind of stuff on a simulator and expect real results until they have been verified by experiment.
And I am very very disappointed that Veritasium didn't actually do a REAL Demonstration to prove it when he posted his video or at least say his next video would show proof.
@Paul Wright The last sentence doesn't make sense, it are moving electrons that cause the poynting field. Arguing about which one is the actual cause of energy is useless, because they always come together. (And that is why Veritasiums video is just bad science communication)
AlphaPhoenix - 2021-12-17
COMMENTS AND CORRECTIONS:
Thanks to Derek at Veritasium for his blessing to make a real-world version of his gedanken experiment. If you haven't seen his video yet, you might want to go watch that for context, and I also highly recommend ElectroBOOM's video on the topic and EEVBlog's video on the topic. Electroboom's video has some simulated scope traces extremely close to what I saw IRL, and a REALLY fantastic animation (8:27) of him waving an electron around in his hand, shedding magnetic fields as it moves (Even though I ignore magnetic fields in this video - I'm trying to think of a test to find out if they matter).
Veritasium https://youtu.be/bHIhgxav9LY
ElectroBOOM https://youtu.be/iph500cPK28
EEVBlog https://youtu.be/VQsoG45Y_00
CORRECTIONS TO THIS VIDEO:
- The most important thing I believe I ignored in this video is the actual, physical distribution of charge in the switch-side wire while the current is starting up. How much charge travels AT the advancing wavefront and how much charge gets stuck along the wire in between the fuzzball I drew and the battery will depend on the physical size of the wires and how close they are to each other, setting their capacitance. This charge distribution also DOES NOT look the same on both sides of the switch, although I drew it that way for simplicity. In a later experiment (next video) my mind melted a bit as I measured the resistors on both sides of the battery and found the current going through them is different. It doesn't change any of the logic I presented in this video, but it makes some diagrams less than perfect.
- It's possible that cross-inductance between the wires contributes to the effect, using almost exactly the same diagram except the wires are connected by a magnetic field rather than an electric field. I couldn't figure out how to decouple these effects day-of, so I'm still thinking on how to test. Hopefully more to come there.
- I'm sure there will be loads more - please leave comments about what I screwed up!
Michael Raasch - 2021-12-17
Love it. I get popcorn for Veritasium's and Electroboom's responses.
Bog Slurp - 2021-12-17
Veritasium blew my mind, and you are piecing it back together again, thank you.
Colinator - 2021-12-17
Electrons can totally leave the wire, if it's hot enough :P
Mr. Rulz - 2021-12-17
d is correct if the switch is near the light bulb because the wires are already charged + and- and then there should be a slight drop and go up again
Fabian - 2021-12-17
Nothing too important, but you used V as the symbol in Ohms law, however V is the unit and U is actually the equation symbol for voltage, just like I is for Amps and R for Ohms,
Love your videos, thanks for educating us all