FAQs and corrections: 1) Someone very correctly pointed out that my final question with the "cutting the line" test was ambiguous. For all of these tests I had the power supply set up as a current source, not a voltage source. If I had been holding a constant voltage at the start and end of the maze (also assuming I would have had thicker wires) the result would have been different =) 2) Multiple commenters have pointed out that the classic “hydraulic analogy” deals with water PRESSURE, not height. This means that we aren’t relying on gravity, so very small changes in pressure can have very large current flows and power transmission, but I think it’s less visual than height and I wanted a visual representation. Also, the pressure at the BOTTOM of the channel actually is higher when there’s more water above it, so it’s almost the same! 2b) I want to take this opportunity to mention the “surface charge” thing. Yes, real charge carriers in a wire spread out the excess charge (positive or negative) by placing excess electrons or depleting electrons, exclusively from the surface (but this only-at-the-surface thing only holds once the system is in steady state). The equivalent here with water is like imagining the water in the bottom of the channel is always present, that’s like the electrons in the bulk of the wire. The “wedge” of water you place on top of it is like the “surface charge”. It’s physically in a different place, and you aren’t actually changing the amount of water in the BOTTOM of the maze, but the wedge drives the slow of water all through the channel. I normally don’t even think about the surface charge because I visualize wires as 1D objects. 3) upon further inspection, I misread my meter when I was looking at the “tall step”. It didn’t read 5 mV, it read 0.5 mV. I think the circuit shorted out somewhere in the lower left just before I made these readings, which would explain why the 70-something number was too low and why the 0.5 number was WAY too low. 4) “The maze should start half full” - you’re right! In electricity, there is a significant driving force to move charge around if a wire has too many OR too few electrons. Wires like to be neutral, and where negative electrons can move, if they abandon the material they leave it with a net positive charge cause the (positive) atomic nuclei have nothing to cancel them out! In the water model you can think of this as actively pulling water from one end of the maze AND actively pushing water into the other end of the maze. But in water, you have to rely on it finding a steady state to flatten out because any stable water level can exist - in electricity it kinda already knows what it wants. 5) A lot of people have likened this to lightning, and lightning is way cool. Unfortunately I don’t claim to understand exactly how lightning “chooses a path”, but it’s more complicated than this. I know it tries many paths at once, but because it has to ionize channels of air do do so, it forms a filamentary structure instead of the more “continuum” flow/wave thing we see in a solid brick of metal. 6) Many commenters have said that I just have an RLC circuit bouncing around. The thin bits of foil behave like capacitors and store some electrons using electric fields, and the magnetic fields around the input wires are coupling to this and making it bounce. YES! This is exactly correct, you’ve just used the more technical wording. I was trying to keep it very linked to the water model so I said electrons were “sloshing”, but that’s exactly what happens in an electronic oscillator. It’s like one of those wave pools hitting resonance! 7) I’ve had a few comments ask what quantum physics has to do with this, and I would say for this experiment, nearly nothing. The reason electrons can flow in metals has a strong foundation in quantum, but it all ends up isotopic so it’s very possible to handle electron flow as a continuum thing. The problem with seeing quantum effects in wires is that electrons like to run into things, and every time they do, they kinda rerandomize. This means that to see quantum effects you need something REDICULOUSLY clean like an ultra pure GaAs/AlGaAs heterojunction with a 2DEG, or your circuit features need to be ridiculously small. A few years ago I had most of an experiment set up to fabricate a wire one atom thick but didn’t have time and tore it down. I’ll absolutely be setting that back up eventually. 8) Local forces - the water molecules can ONLY interact with (and sort of exchange information with) their adjacent molecules, but that’s plenty for them to solve a maze like this. Each individual water molecule doesn’t even know that it’s IN a maze, but the collective is able to solve it - I think that’s really beautiful. Electricity on the other hand, DOES have some longer range forces, and this was demonstrated very well by the Veritassium experiment I set up for real in the field. The thing is, all of these long-range forces can’t actually DELIVER electrons - nothing’s moving down a wire, which means that the results from these forces are always temporary, and if you want a DC current to flow, that’s still set up by relatively local forces between nearby electrons behaving like water. 9) a LOT of comments are recommending slomo guys. A 10million FPS camera would take a frame every 100ns. That would skip right over the larger sloshing/ripples that I said were way too slow. Electricity is mind-bogglingly fast!
If you used a properly doped semiconductor, would it be possible to create a maze where the electrons flowed preferentially through one path but holes through a different path?
Using thermal imaging to trace the current is a really great idea. I taught Physics for 33 years before retiring 7 years ago, and I wish I had thought of this demonstration. I really did not see any errors in your explanation, good work.
You can suggest it to every physics teacher you meet. Just because you can't teach with this method any longer doesn't mean you cannot suggest this to other physics teachers. Spreading knowledge to other teachers is just as important as spreading it to the students.
Thermal imaging is also an incredible way to help diagnose bad circuit boards. If you look at a powered board under thermal and see one extremely bright spot, you've almost certainly just found where an IC unit shorted out.
@@graealex That's actually a fun idea, just increase the current until it starts glowing a bit. I'd imagine aluminum foil probably has a very narrow area between "glows a bit" and "melted" though because it's so thin. Alternative idea that comes to mind: Put the foil down flat on a piece of thermal printer paper (the stuff used for receipt printers), just hold it down with a wood or acrylic plate. It'll take a little tweaking to get the "exposure" right but there should be a combination of current and on-time that darkens the paper juuust right so you can see the pattern on the paper after you take off the foil.
@@Ethan-ej6fz Yes they do. Just in that case, the resistance is such a high number the current is effectively zero. There's no such thing as an insulator.
@@Ethan-ej6fz There is current flow when you introduce a new voltage to an open circuit. It's like when you charge a capacitor, there is current flow until it "fills up" on voltage and then the current effectively stops.
@@Ethan-ej6fz When I said "Path", I meant successful paths of varying complexity. I did not mean interrupted paths. A path, to me, goes from source to destination. But I see your point.
You might say that the field includes all paths. The current follows the path of least resistance through the field so electrons are more likely to appear on that path.
I was watching Steve’s video and at first I wanted to do the vacuum test, but then thought about it some more and the whole “built up pressure in the closed off bits” thing reminded me SO much of electricity I had to do it! I was thinking about this on a Friday while driving away to an FRC competition but you better believe that on Monday night after I got back I was in the garage cutting foil 😁
@@d.6325 Yeah I guess this is what you may call an Abacus with extreme mechanical princebles at play, I think the very First calculator ever made was the size of a small car?
Ever since I was in high school, I ALWAYS had an issue understanding how electricity flowed in series and parallel circuts (and combinations of such) with resistances. I never got a straight answer on whether or not current existed on the path with more resistance. This has helped solve that decade-long mystery for me. THANK YOU!
The short answer is "of course." The longer answer would be to measure the current through the higher resistance path. Your HS profs probably didn't have the equipment nor the time to do this.
You must have had some poor teachers because you should have learned how to calculate potentials (voltage) and current in each branch of your circuit as well as the potential drop across each resistor and current through each resistor.
@@philipgwyn8091 Ohms law says V = R * I. So by just measuring the voltage across a resistor, you already know the current. (Assuming the resistor network has significantly less resistance then your voltage meter). Most High School teachers just have no idea what they are talking about when it comes to electricity. You see that phenomenon the strongest in Physics education in Electrical/Electronics Engineering Programms: Physics education starts with Water and then teaches Resistor networks as analog to Water flow. Students in EE Programm gain intuition in current flow in Electronics 101 and then use the associations for electricity in water models in physics (exactly flipped on how the physic instructor teaches it)., because electricity is - after having it learned once - more intuitive then water. In electricity, we easily assume wires to have negligently low resistance; with water, a pipe (or any component including connectors) is always a significant resistance. Sure, you can show me cases where the resistance of an electrical wire and connector also matter, but when you reach that point, you already know to add a resistor symbol to your schematic, even if you latter assume it to be 0.
Why did you never got a straight answer? Did you ask? This is standard highschool stuff that I teach (especially, because I hate people saying "electricity takes the least resistance way", because, as you just saw, this is just wrong.
It's very nice seeing so many Physics UA-camrs duplicating experiments using different methods, but getting similar results. My understanding of these different concepts is increasing because of this. Well done. I especially like the 1 light second power transfer experiments by you and many others.
yeah learning the same thing from different sources is the best thing to do I think. There's always someone missed or someone added extra and you can get some average of all you learned
An idea for the water maze; block the entrance and exit and fill with clear water, then fill the ‘input’ with died water. Unblock the start and end and the stagnant zones should stay clear with the solution turning the died color. Great video!
Yeah, I was going to suggest the same idea. You could also start it running with clear water to let it find its equilibrium and then add dye to the input while it's running. It would eventually diffuse into the stagnant mesas, but you could see the color front solving the maze in real time.
he has already basically done this when he filled the dead-ends with new clear water. It wasnt the point of the demonstration but you could see the entire maze went clear and then the correct path started bluing again @ 7:50
Note that you have to start with flowing clear water for this to work. When there's no flow at all, the water level is the same in the whole maze. So when the flow starts, the level in the "upper" parts will rise (adding dyed water) and the level in the "lower" parts will sink. And BTW, there still is an exchange on a molecular level (from temperature) and on a macroscopic level from turbulence. So over time, the dye will bleed into the branches.
@@ricolorenz7307 Careful, I'm tempted to rant about how English has no logic in which words swap between y/i/ie (while still sounding the same!) for their different forms... ;)
I'm currently a PhD student and about to publish a paper discussing spatial dependence of microscopic percolation conductance. We are studying the case of a conductive 2D lattice (essentially a maze), and although we use computer simulations to do thousands of runs (since we are interested in the average conductance) this video was still very illuminating. Thank you so much :)
sorry to say this but if you're a phd student about to publish a paper on the subject and this is your FIRST TIME watching this experiment being conducted, ain't there something very, very wrong with the current educational system? i'm flabbergasted.
This finally explains how electricity follows the path of least resistance. The backing up of the other routes forces the electrons to go the quickest, and least resistant route. I've had this question in my mind for a while and I finally have an answer. thank you
For the oscilloscope test, you should have used a capacitor instead of your power supply. You could show, side by side, the discharge curve of both the maze vs a simple resistor with equivalent resistance to the maze. Any deviation from the resistor curve would be the "electrons sloshing around the maze."
When I was in grade 6 I kept asking the teacher when we did our introduction to electricity unit "but how does the electricity know what's ahead of it, how does it decide where to go?" I like that you decided to cover this subject a lot, I have a better understanding now but you always make very informative and entertaining videos. I kind of thought I knew the answer when I started thinking of electricity like water and that made a lot more sense to me but I'm excited to see the video and see if I can get a more comrpehensive understanding.
This is why I have the notifications turned on for this channel from day one, I have been pontificating the particles/waves,, Thank you and keep up the great work, I can see this channel reaching 1M+ soon!
Years back I majored in mechanical engineering and I still remember how much the fluid dynamics course blew my mind. When I learned how well everything in FD had a near perfect analog with electrical circuits it felt like things finally clicked in my head. Instead of living in a world with a near infinite amount of things all following their own principals and laws, most everything was more or less just different forms of the same fundamental objects and mostly seem to follow a relatively small and simple list of principals. It gives me hope that one day we may end up finding solutions to things like quantum gravity and the rules aren't as different as they look right now with our limited understanding.
And thermal, and dynamics, the analogies abound. But they are NEVER perfect, they always fall completely apart at some level. I used to like to think of capacitors like buckets, inductors like flywheels, voltage and current like pressure travel and flow in a rigid pipe, etc. Like I said, everywhere. My old man, at the start of his career, used to design analog circuits to simulate missile or helicopter blade dynamics, bending moments, stability and such. And yeah, fluids was a fun, but not super easy course...compared to Dynamics though, it was fairly easy, at least for me. My dynamics prof, first day, walked in and said F is ma, you can go home now. Right, and then soon we were into Coriolis, etc. He also said he'd keep the numbers reasonable, so if you calculated the weight of a guy in an elevator to be three tons, you did something wrong. There was a big hint there. :-)
I took fluid dynamics my senior year studying electrical engineering. The professor -- who was dean of engineering -- told us EE students could sleep through the fluid circuit stuff. He wasn't far off. I spent the time trying to think of fluid analogies for capacitors, inductors, and transistors...
Read the book: Principia Mathematica 2: A Complete Toolkit for Hacking the Physical Universe, by Robert and David Dehister. They have a physical model of the matter-in-motion expressed with simple principles. They are able to describe electricity, gravity, light and magnetism in a simple manner.
I have a technical degree in electricity and took several circuits and electronics classes for a Computer Engineering degree. This one single video explained how electricity works and answered questions I've been trying wrap my head arouns for years. In 20 minutes. Bravo. Thank you so much, and I look forward to your future videos explaining electricity using water that you mentioned.
Been working with electronics at the hobby level for years, and this has always been something I *know*, but never intuitively understood. One demonstration and everything immediately clicked into place. Love it, good work man!
I'm was an electrical engineer and I can safely say that your channel is the best explainer of how electricity behaves out there. Bravo, keep it up. I've binged your videos
I am falling further and further down the rabbit hole of the scientific side of youtube and I am nothing but hyped for the journey. Thank you for having incredibly simplified yet also complex descriptions and explanations. It ensures my attention is held no matter what level of understanding I have at the moment. Amazing content. Thank you.
man I wanted today to learn about antennas and im in EM waves, magnetism and electricity rbithole for last 8 hours... 4;30 am and I should sleep already
a great thing i like about your video is, unlike most others who wait till the very end of a 500 hour video before telling you the result-which makes viewers feel like getting tricked into helping monetize the video-it shows you the summary and actual secret right at the beginning, and shows in depth processes in the rest of video.
I've recently started working with circuits and it's really interesting how this "self-balancing" mechanism translates to the simple rules we were explained in class
Those 5ns riples are reflections in your maze. Touching the wire is producing diraque pulse which is propagated thru your maze. Every end or blind end will reflect that pulse back to source which depends on impedance. Add capacitance, inductance and resistance to your theoretical model and you will get your voltage readings on your scope. You can even do FFT of your response curve and you will find out that there are certain frequencies peaking up. Those are based on length of each branch in your maze. Each branch is now also a peace of tuned RF antenna. And remember, electrons are very slow in conductive material, the interaction between the electrons and overall propagation are what is almost as fast as light in vacuum.
Also, remember as electrons pass a gap they WILL generate RF. That's how RADAR and Klystrons works essentially. That maze is probably noisy as all get out in the RF spectrum.
@@PigeonLaughter01 You say RF, I say black magic. Then again, the difference between a Computer Engineer and an Electrical Engineer is I didn't have to take Emag.
Love this channel. As a corrosion specialist who works on pipelines, i.e. cathodic protection, ac powerline interference, materials engineering, etc, i think this channel might be my favorite. I really like how excited you get about the science. Awesome job.
Nice demonstration! It always delights me when someone takes precious time to describe complex things in a simple way, thank you. The whole maze/path setup is a perfect example of sheet resistance, too.
What a beautiful video. You tied together several high and low-level concepts of electromagnetism and with wonderful visual examples that are easy to parse quickly. Great work, I truly enjoyed this!
I love the water example. I don't see it as the input "pushing" the stream through the maze but rather the output "pulling" the water through a predefined path. As if you pull a string through the maze solution.
In reality it’s both! Mhedi made a great point like this in his video with Derek - you’re pulling on one end of the chain and pushing on the the other end of the chain at the same time - both actions deliver torque to the sprocket
@@AlphaPhoenixChannel See how if you have a barrel of water, a hose and a pump - you can put that pump at the end of the hose with the hose on it's inlet and other end in the water and it will suck the water from the barrel. Is there an electrical equivalent for that? It's negative pressure when you're 'sucking' water - is there some sort of negative electrical pressure too?
@@alflud There is! Conductors like to be neutral, so if you pull electrons out of a conductor, other electrons will be drawn in from anywhere they are available. In reality, it's not a vacuum of electrons, but a charge imbalance, because when you remove electrons you don't remove the associated positively charged nuclei, and that section of the material gets a NET positive charge. That net positive charge and the associated fields attract more negatively charged electrons. Hope that made sense
@@alflud Yes, the cathode repels electrons while the anode attracts electrons so its like a pump pushing water at one end while "sucking" water at the other.
@@wayneyadams It's kind of both at the same time, but really a circuit is just that, a round circuit of wire that has to connect back on itself, a loop. In that sense, the pump is really what the battery is doing.
I love the water model for electricity! It's what really solidified my understanding of fundamental electronics. Looking forward to the (hopefully) coming video :)
I'm an electronics engineer and I thought of the electromagnetics of the foil maze which I understand quite well, and that actually gave me insight into the water maze haha
@@__dm__ When obsessing electronics students, it is always a good sign when they start to use electricity as a model for water system. Really funny when the physic instructor tries to explain electricity with water models to EE students and they apply the tabels in reverse, because electricity becomes more intuitive then water after solving various resistors networks in Electrical Engeering Classes.
My guess for mazes with two solutions is that each path has some resistance R1 or R2. Given a uniform material, any one length of material in one path will have the same resistance as the same length in the other path. So the resistances are proportional to the length of the path. The current will split such that is split between the two in the ratio R1 to R2. So the less resistant path will see more current. The power dissipation is P = U * I. The voltage drop across both resistors is the same because they are connected, so the shorter path with more current will heat up more. The maze with two paths is equivalent to two resistors in parallel, which is grade 5 physics textbook stuff.
Great video as usual. Two things I would have liked to see: 1. When you poured clear water onto the maze but kept pumping dyed water it would have highlighted the solution very nicely. 2. Multi-path water mazes. Maybe starting with clear water flowing and adding a dye tablet in the source basin would have yielded different strengths of colour in the two paths.
I think with adding dye to a multiple-path water maze, they would both end up the same color, but the dye color would propagate more quickly through the shorter path due to the faster-flowing water.
Your multi-path experiment reminds me of a similar idea I had many, many years ago when I was much younger. Way before GPS was a thing I drove a cab for a couple of years. Routes driven were highly subjective and may or may not have been optimal but paper maps helped in many cases. My idea was to create a road map using lengths of wire to represent streets and each intersection would be the relevant wires joined at the junction. At the mid-point of each street between intersections, there would be a small bulb that would light when the current passed that point. One-way streets would be controlled by diodes in the circuit and in an improved version, speed limits would be controlled with resistors in the circuits. The ultimate thought was that probes would be clipped onto the starting and ending points, and a string of lights would show the shortest (and quickest) path to take. I never got to a testing stage with the idea which is just as well since the covered area of 750 square miles had over a thousand streets covering over 500 miles and probably a dozen or more ways to get from point A to B. The resulting map would be totally unmanageable in size and either all the bulbs would light or, more likely, none would be bright enough to see.
This has opened up a whole new level of intuition for me about voltages, resistance and current flow. As an electronics student I had already worked out one way of thinking about these things, but to see voltage as a change in "height" has finally satisfied my question of what potentials really were. In a uniform gravitational field, height is equal to the potential energy per unit mass and likewise electrical potential is the potential energy per unit charge. Also very interesting to work with wires of roughly uniform resistance like this - makes the current flow much more intuitive than with wires with almost zero resistance connecting components with a much higher resistance proportionally. Thanks Brian, for explaining things in the way that only someone with a good understanding can! Have a good one :)
Showing how hard it is to measure transients on the order of a few nano seconds is such a contribution to viewers! It's a very valuable practical lesson in many ways. It is made all the more effective with the high spirits you keep as you fail to get a conclusive measurement. Respectable work!
I was not a "physics" person in school and I absolutely love your videos! Thank you so much for sharing these with those of us who "didnt get it" in school!
this just gave me a great idea for a D&D scenario. The players find themselves in a dungeon maze and there's an aqueduct near the entrance. Maybe there's already a leak in the aqueduct with a little stream running down into the dungeon and some wood barrels near the entrance to give the players a hint on how to solve it.
Great video, just a couple recommendations: 1) What about glueing the mazes to some kind of base to avoid annoying perturbations in your tests? 2) As a cheaper alternative to lasser cutting... you can use conductive 3D printer filment instead 😊. Thanks for the interesting video!
I've loved watching your channel grow. From all your subscribers to your Ph. D., I just wanted to say "Congratulations!" Thank you for all of the wonderful content!
Awesome video! The way you explained it is so intuitive and easy to understand with examples and refering back to simple concepts. I wish I had this back when I first learnt about electricity
"how does current find the 'path of least resistance' " is something I've honestly questioned for a very long time (but was too lazy to do real research lol) thank you so much for laying out the perfect answer so clearly!
Wow, that was a lot of work but it was definitely worth it because this demonstration was every bit entertaining as it was educating. Really nice explanation of everything.
While watching this I had three thoughts. 1. After a four year physics degree, I think I would prefer to have had Alpha Phoenix as my high school teacher, than my university lecturer. Your ability to take complex and even controversial topics and make them accessible is fantastic and all young people should watch your work. 2. I am quite obsessed by super-high time-resolution photography of stepped leaders. Obviously an oscilloscope is going to have trouble seeing the EM fields, feeling their way around a maze. But perhaps a huge maze with atomic clocks scattered around could allow us to see the equivalent of stepped leaders in an electrical circuit? 3. In the very last pictures, why does the circuitry heat up so much more, at the corners of the maze? I get how, for example, racing cars have friction when they get to the corner. But how do EM fields or electrons know to expend more energy at the corners of a maze? I am fascinated by that picture!
I'm sure someone else said it in the 1000+ comments, but that last demonstration was also a good explanation of why an inadvertent low-resistance path is called a "short circuit" and why it's a problem.
This is an awesome visualization! It also makes the formulas and calculations in electronics more logical to me. In the end, all electronic circuits are basically just a maze, where the measure of resistance of a certain component tells you how "long" that component's "path" is, and the voltage drop over a series of components gives you the "gradient" of the "water hill"
A good way to think about it is that once the shortest path has been found, it's like a pulling motion from the end of the maze, rather than a pushing motion from the beginning. Now the water is being pulled through the maze from the end of the maze, so it's always following that path (despite very small deviations here and there).
That's a way to _think_ about it, but it does not correctly portray a solution. The solution is in the video, and it is not in theoretical equivalence with any pulling mechanism.
Yes it's theoretically equivalent to think about it this way, the pressure differentials along the path are what define this behavior, and that two-way equilibrium is only established once the path has been located. The added tugging force (pulling motion/negative pressure) is what allows for this path to dominate over the other paths. Without it, as you can see when the maze is closed, or when it hasn't located the path yet, there is nothing to enforce that particular path. So it is more clear to think about this from the opposite end once the path has been established, as this is what is maintains that behavior. It works the same way with the electricity example as well, negative and positive EM radiation pressure. @@-danR Btw, the "solution" (it's not a solution) is wrong. This is not caused by water level, that is just an observational byproduct. You can read his pinned post that confirms this as well if you need to appeal to an authority.
Instead of pulling, I like to think about it like the electrons get out of the way. Imagine rolling a basketball down a highway of AI driven cars (all going the same speed). The ball will follow the path of least resistance.
I'm guessing that the electricity will treat each valid path like a parallel resistor. A larger portion of the total current will pass through the shorter path.
Excellent demonstration of the concept of why trying to increase capacity of wires by adding separate wires is fraught with problems, and yet it works when people do manage to run equal lengths in their DIY setups
The electrons in current move extremely slow, but electrons are tiny and their force is strong. Through the entire life of a power plant, the electrons in the main conduit may never leave the premises, but they force other electrons to move, which force other electrons to move, and can move electrons hundreds of miles away
So following the water analogy, the flow of "current" is the gradient of the pressure of the water in maze. (Actual hydro-engineer or physicist correct me.)
From high school physics, the elections themselves move down a wire about as fast as the hour hand of a clock. It's slow on our scale, but not overwhelmingly so.
This was a great video. A slightly more technical way to put it that is also helpful is that all conductive material, including wires, have capacitance. A capacitor is like an electric spring, same equations as a spring. Compressing the electric spring is the same thing as the filling up of the maze with water. When the voltage is removed, they will "slosh" out, or sort of pushed out like a spring releasing compression, as the charge of the maze reaches 0 again. I always found the spring analogy helpful.
Id be curious to see if the path for those multipath mazes changes if you changed the cross section area of the foil at different points. Id expect thinner parts to maybe act like resistors. If that was the case it would still make sense with using water as an analogy for electricity.
Yup! A thinner path would behave like a longer path, and it IS still very well-represented by the water height=voltage shtick! I shoulda done that… Actually come to think of it I kinda did with water! For the 2-path water demo, I had one that was printed the same width as the maze channels and it wasn’t dropping enough voltage -I mean height- so I thinned the channels to 2mm wide 😁
This would be interesting to see. I understand that the paths for current are acting like resistors and longer paths lead to higher resistance. I also get that thinner paths have higher resistance. Would be interesting to see the pattern of a solid sheet of foil. The part that is confusing to me is the real world application. From soldering simple analogue circuits, the gauge of wires or traces doesn't really seem to make any difference, I guess since the scale is so far off from the resistor components etc. Thanks for the videos and comments!
@Robert Swaine A weir is indeed weird It completely blocks flow under a certain threshold, and once over that threshold its resistance goes down as potential goes up. What electronic doohickey does the same?
@@Hirosjimma I think what's really going on is in a Forward bias situation you get an exponential relationship between voltage and current. But when you're in a reverse bias you get a really small current until you surpass the breakdown voltage. I think it's also good to represent that in terms of current and voltage because diodes are typically shown in terms of their IV curves (current vs voltage). Just like how a diode behaves, the band structure even looks almost the same as the physical weir. But also like the weir and a diode, you need a small forward bias to go down the weir, but a large reverse bias to go the other way, until you get to the breakdown voltage.
Thank you for correcting the common misstatement, "electricity follows the path of least resistance." In fact, the current flowing in each circuit corresponds indirectly to its resistance, but current will flow in all available paths.
We use the saying...."path of least impedance" at work. It's a good way to always remember that a lot of devices or circuits use both AC and DC and it reminds you that capacitive reactance and inductive reactance can play be huge factors in how that circuit operates.
Honestly this is how voltage should be demonstrated. It’s so much easier when you use examples involving more paths than explaining voltage with a single path (like a lot of demonstrations do).
Great video and great explanation. I like that you say the electricity is taking both paths. The phrase "electricity takes the path of least resistance" implies that it does not take other paths of more resistance. If this was true then each power plant could only turn on one light bulb, the brightest one. Electricity takes every path it can.
I love the vocabulary that you use. It mixes will with what you're trying to describe. Maybe you're just that good. Maybe we're just similar. Whatever the case, I enjoy your videos A LOT!
Very nice experiment! It illustrates Kirchhoff's circuit laws in an interesting and engaging way. The different paths to "solve" the labyrinth are wires of different lengths and can be seen as resistances of different values. For two resistors in parallel, more intensity will flow through the least resistant one and so it will heat up more.
Thank you so much for the point about anthropmorphizing systems and giving the real system. Past Me from highschool was continuously so frustrated by teachers in science classes saying a beaker of chemicals wants to be in a lower energy state with no further explanation. Or any of a thousand other examples. It's a useful shorthand, but it's important to peel back that layer of abstraction and figure out *why* a system "wants"' anything.
Absolutely fascinating. I understood most of this already, but you've helped me visualize it in an entirely new way. Only 8 mins in, but already I can see how resistance is essentially drag created on the "electron water" and an item being conductive basically just means the water in the maze is already filled (the way electrons are already in the material and don't ACTUALLY flow like water) So basically I'm assuming that by the very nature of how resistance works, plus the 'gravity' model of the flow finding the path, the fact that resistance even exists is what actually allows electricity to follow the path, as it is basically testing all paths at the same time, but only the path with an output can 'move' and this 'low pressure zone' creates a metaphorical vacuum that then creates the flow of electrons. This is my favourite vid of the year, thank you so much! (I'm gonna keep watching now, I assume there is plenty more to learn)
cutting the wire at the end was somehow both surprising and completely understandable. At first I interpreted as the flow getting trapped in the bends (and promptly realized how silly that was) and then realized this is heat, not actual flow, and the corners will have the highest concentration of heat due to the proximity to other areas of the 'wire'. But it did also highlight the flow, in that because the metal heated up SO much slower than the electricity flowed, you can actually still see (from top to bottom) that it is filling in as it goes from start to finish. Yep, absolutely fascinating and a really beautiful illustration that truly cemented the concept in an accessible way. Great work!
1:43 awesome quotable line 5:10-5:30 I REALLY liked this part. 8:00 boy, that's a lot of systems. 15:38 this is a very good defense of the water explanation for electricity. 20:08 it feels like ideas work this same way. 22:14 this is really satisfying
Awesome analog. The "instantaneous" speed at which the electrons flow, sounds like a challenge you should throw down to the Slo-Mo Guys to see how the IR response looks. Thanks, man, for sharing.
Great video loved the callbacks to Grady and Steve's uploads, other great channels covering theory with helpful practical examples. Loved thoughts being confirmed by the excel visualization. Had a jump saying "back to equilibrium" out loud then thinking maybe that wasn't the right word and was immediately followed up by the video saying it too
Absolutely fantastic work ! You are teaching and creating true deep interest in science, Something we really need today more than ever. If I was wealthy, I would fund you for 20 years of experiments. Thank you so much.
Now that is a surprisingly interesting and intriguing information! Never really got an explanation of how electricity finds the path of least resistance. Very interesting
I thought the same many times. And then 1 day i realise current is not flow to the shortest path. Current always flow with least resistance. And after watched your video I confirm. Thanks man 🎉🎉 For Example if we have two types of wires first wire is 1 meter long and other one is 10 metre long but has 10 times less resistance compared to first one then the current flow on the both wires is same . If you read my comment please reply me if i was right 👍
Thanks so much for such a great video. It really makes sense now how electricity follows the least resistance path, It's not because it always knew where to go but because it "test" all the paths! And choose the one that takes the less effort to complete. You just won a new subscription!
FAQs and corrections:
1) Someone very correctly pointed out that my final question with the "cutting the line" test was ambiguous. For all of these tests I had the power supply set up as a current source, not a voltage source. If I had been holding a constant voltage at the start and end of the maze (also assuming I would have had thicker wires) the result would have been different =)
2) Multiple commenters have pointed out that the classic “hydraulic analogy” deals with water PRESSURE, not height. This means that we aren’t relying on gravity, so very small changes in pressure can have very large current flows and power transmission, but I think it’s less visual than height and I wanted a visual representation. Also, the pressure at the BOTTOM of the channel actually is higher when there’s more water above it, so it’s almost the same!
2b) I want to take this opportunity to mention the “surface charge” thing. Yes, real charge carriers in a wire spread out the excess charge (positive or negative) by placing excess electrons or depleting electrons, exclusively from the surface (but this only-at-the-surface thing only holds once the system is in steady state). The equivalent here with water is like imagining the water in the bottom of the channel is always present, that’s like the electrons in the bulk of the wire. The “wedge” of water you place on top of it is like the “surface charge”. It’s physically in a different place, and you aren’t actually changing the amount of water in the BOTTOM of the maze, but the wedge drives the slow of water all through the channel. I normally don’t even think about the surface charge because I visualize wires as 1D objects.
3) upon further inspection, I misread my meter when I was looking at the “tall step”. It didn’t read 5 mV, it read 0.5 mV. I think the circuit shorted out somewhere in the lower left just before I made these readings, which would explain why the 70-something number was too low and why the 0.5 number was WAY too low.
4) “The maze should start half full” - you’re right! In electricity, there is a significant driving force to move charge around if a wire has too many OR too few electrons. Wires like to be neutral, and where negative electrons can move, if they abandon the material they leave it with a net positive charge cause the (positive) atomic nuclei have nothing to cancel them out! In the water model you can think of this as actively pulling water from one end of the maze AND actively pushing water into the other end of the maze. But in water, you have to rely on it finding a steady state to flatten out because any stable water level can exist - in electricity it kinda already knows what it wants.
5) A lot of people have likened this to lightning, and lightning is way cool. Unfortunately I don’t claim to understand exactly how lightning “chooses a path”, but it’s more complicated than this. I know it tries many paths at once, but because it has to ionize channels of air do do so, it forms a filamentary structure instead of the more “continuum” flow/wave thing we see in a solid brick of metal.
6) Many commenters have said that I just have an RLC circuit bouncing around. The thin bits of foil behave like capacitors and store some electrons using electric fields, and the magnetic fields around the input wires are coupling to this and making it bounce. YES! This is exactly correct, you’ve just used the more technical wording. I was trying to keep it very linked to the water model so I said electrons were “sloshing”, but that’s exactly what happens in an electronic oscillator. It’s like one of those wave pools hitting resonance!
7) I’ve had a few comments ask what quantum physics has to do with this, and I would say for this experiment, nearly nothing. The reason electrons can flow in metals has a strong foundation in quantum, but it all ends up isotopic so it’s very possible to handle electron flow as a continuum thing. The problem with seeing quantum effects in wires is that electrons like to run into things, and every time they do, they kinda rerandomize. This means that to see quantum effects you need something REDICULOUSLY clean like an ultra pure GaAs/AlGaAs heterojunction with a 2DEG, or your circuit features need to be ridiculously small. A few years ago I had most of an experiment set up to fabricate a wire one atom thick but didn’t have time and tore it down. I’ll absolutely be setting that back up eventually.
8) Local forces - the water molecules can ONLY interact with (and sort of exchange information with) their adjacent molecules, but that’s plenty for them to solve a maze like this. Each individual water molecule doesn’t even know that it’s IN a maze, but the collective is able to solve it - I think that’s really beautiful. Electricity on the other hand, DOES have some longer range forces, and this was demonstrated very well by the Veritassium experiment I set up for real in the field. The thing is, all of these long-range forces can’t actually DELIVER electrons - nothing’s moving down a wire, which means that the results from these forces are always temporary, and if you want a DC current to flow, that’s still set up by relatively local forces between nearby electrons behaving like water.
9) a LOT of comments are recommending slomo guys. A 10million FPS camera would take a frame every 100ns. That would skip right over the larger sloshing/ripples that I said were way too slow. Electricity is mind-bogglingly fast!
Not a mess-up, but a simple consumer-grade Cricut machine will cut your foil maze out very easily and with little danger 😃
@@OrigamiMarie yeah but that wouldn't have been as cool haha
@@Mezzo_Roo true!
is it kirchoffs current law? States current remains the same at all points of a series circuit? Just taking a stab.
If you used a properly doped semiconductor, would it be possible to create a maze where the electrons flowed preferentially through one path but holes through a different path?
Using thermal imaging to trace the current is a really great idea. I taught Physics for 33 years before retiring 7 years ago, and I wish I had thought of this demonstration. I really did not see any errors in your explanation, good work.
You can suggest it to every physics teacher you meet. Just because you can't teach with this method any longer doesn't mean you cannot suggest this to other physics teachers.
Spreading knowledge to other teachers is just as important as spreading it to the students.
Or just crank up the current until the thermal radiation decides to enter the visible spectrum 😅
@@Operational117 I would except that I have not been in touch with any teacher since i retired.
Thermal imaging is also an incredible way to help diagnose bad circuit boards. If you look at a powered board under thermal and see one extremely bright spot, you've almost certainly just found where an IC unit shorted out.
@@graealex That's actually a fun idea, just increase the current until it starts glowing a bit. I'd imagine aluminum foil probably has a very narrow area between "glows a bit" and "melted" though because it's so thin. Alternative idea that comes to mind: Put the foil down flat on a piece of thermal printer paper (the stuff used for receipt printers), just hold it down with a wood or acrylic plate. It'll take a little tweaking to get the "exposure" right but there should be a combination of current and on-time that darkens the paper juuust right so you can see the pattern on the paper after you take off the foil.
They take all paths. The less resistance, the more current flows thru that path.
In the case of a maze that wouldn’t be true. All paths that don’t lead to the exit would be considered as open circuits, and no current would flow.
@@Ethan-ej6fz Yes they do. Just in that case, the resistance is such a high number the current is effectively zero. There's no such thing as an insulator.
@@Ethan-ej6fz There is current flow when you introduce a new voltage to an open circuit. It's like when you charge a capacitor, there is current flow until it "fills up" on voltage and then the current effectively stops.
@@Ethan-ej6fz When I said "Path", I meant successful paths of varying complexity. I did not mean interrupted paths. A path, to me, goes from source to destination. But I see your point.
You might say that the field includes all paths. The current follows the path of least resistance through the field so electrons are more likely to appear on that path.
Never thought I'd see a voltage divider in maze form. Incredible.
I was watching Steve’s video and at first I wanted to do the vacuum test, but then thought about it some more and the whole “built up pressure in the closed off bits” thing reminded me SO much of electricity I had to do it!
I was thinking about this on a Friday while driving away to an FRC competition but you better believe that on Monday night after I got back I was in the garage cutting foil 😁
How do we create a depletion zone with water?
I mean, is it possible to have a transistor for water?
@@monad_tcp ua-cam.com/video/PtXgewzT1Fo/v-deo.html
@@d.6325 Actually, I think Steve Mold even had simple water-based adder for couple of bits
@@d.6325 Yeah I guess this is what you may call an Abacus with extreme mechanical princebles at play,
I think the very First calculator ever made was the size of a small car?
Awesome experiment!
Imagine all of these youtubers collaborated together to make the best video ever.
@@gallium-gonzollium ok, now I need that.
Just don't short it !!
@@gallium-gonzollium Melting lipstick...? (IM KIDDING)
@@gallium-gonzollium They set up the coolest circuit ever. Linus accidentally drops something and somehow Mehdi is still the one that gets shocked.
For me, as an engineer, watching this video is like relaxing in a forest near a lake in springtime. Thank you for this effort.
Same, which is why nobody outside of scientific community wants to hang out with me 😢😂
Ever since I was in high school, I ALWAYS had an issue understanding how electricity flowed in series and parallel circuts (and combinations of such) with resistances. I never got a straight answer on whether or not current existed on the path with more resistance. This has helped solve that decade-long mystery for me. THANK YOU!
The short answer is "of course."
The longer answer would be to measure the current through the higher resistance path. Your HS profs probably didn't have the equipment nor the time to do this.
You must have had some poor teachers because you should have learned how to calculate potentials (voltage) and current in each branch of your circuit as well as the potential drop across each resistor and current through each resistor.
@@philipgwyn8091 Ohms law says V = R * I. So by just measuring the voltage across a resistor, you already know the current.
(Assuming the resistor network has significantly less resistance then your voltage meter).
Most High School teachers just have no idea what they are talking about when it comes to electricity.
You see that phenomenon the strongest in Physics education in Electrical/Electronics Engineering Programms:
Physics education starts with Water and then teaches Resistor networks as analog to Water flow.
Students in EE Programm gain intuition in current flow in Electronics 101 and then use the associations for electricity in water models in physics (exactly flipped on how the physic instructor teaches it)., because electricity is - after having it learned once - more intuitive then water.
In electricity, we easily assume wires to have negligently low resistance; with water, a pipe (or any component including connectors) is always a significant resistance.
Sure, you can show me cases where the resistance of an electrical wire and connector also matter, but when you reach that point, you already know to add a resistor symbol to your schematic, even if you latter assume it to be 0.
@@wayneyadams bro
Why did you never got a straight answer? Did you ask?
This is standard highschool stuff that I teach (especially, because I hate people saying "electricity takes the least resistance way", because, as you just saw, this is just wrong.
It's very nice seeing so many Physics UA-camrs duplicating experiments using different methods, but getting similar results. My understanding of these different concepts is increasing because of this. Well done. I especially like the 1 light second power transfer experiments by you and many others.
thhx now i know what to look for next! appreciate that 1 C sec tip
yeah learning the same thing from different sources is the best thing to do I think. There's always someone missed or someone added extra and you can get some average of all you learned
An idea for the water maze; block the entrance and exit and fill with clear water, then fill the ‘input’ with died water. Unblock the start and end and the stagnant zones should stay clear with the solution turning the died color.
Great video!
Yeah, I was going to suggest the same idea. You could also start it running with clear water to let it find its equilibrium and then add dye to the input while it's running. It would eventually diffuse into the stagnant mesas, but you could see the color front solving the maze in real time.
he has already basically done this when he filled the dead-ends with new clear water. It wasnt the point of the demonstration but you could see the entire maze went clear and then the correct path started bluing again @ 7:50
Note that you have to start with flowing clear water for this to work. When there's no flow at all, the water level is the same in the whole maze. So when the flow starts, the level in the "upper" parts will rise (adding dyed water) and the level in the "lower" parts will sink.
And BTW, there still is an exchange on a molecular level (from temperature) and on a macroscopic level from turbulence. So over time, the dye will bleed into the branches.
*Dyed
@@ricolorenz7307 Careful, I'm tempted to rant about how English has no logic in which words swap between y/i/ie (while still sounding the same!) for their different forms... ;)
I'm currently a PhD student and about to publish a paper discussing spatial dependence of microscopic percolation conductance. We are studying the case of a conductive 2D lattice (essentially a maze), and although we use computer simulations to do thousands of runs (since we are interested in the average conductance) this video was still very illuminating. Thank you so much :)
Sounds fascinating! I always liked the percolation problem.
sorry to say this but if you're a phd student about to publish a paper on the subject and this is your FIRST TIME watching this experiment being conducted, ain't there something very, very wrong with the current educational system? i'm flabbergasted.
Microscopic percolation? Is that so you can make coffee for some little critters?
@@rodsmade universities only exist to train the youth to be Marxist activists
@@AnnaBananaRepublic Maybe Starbucks for narcoleptic kleptomaniacs 😆
This finally explains how electricity follows the path of least resistance. The backing up of the other routes forces the electrons to go the quickest, and least resistant route. I've had this question in my mind for a while and I finally have an answer. thank you
For the oscilloscope test, you should have used a capacitor instead of your power supply. You could show, side by side, the discharge curve of both the maze vs a simple resistor with equivalent resistance to the maze. Any deviation from the resistor curve would be the "electrons sloshing around the maze."
interesting, you assume the maze is an inductor and the "sloshing" would be an LCR resonance circuit.
@@sarowie What do you think ISN'T an inductor?
@@dkosmari Still very mad about the time I was diagnosing a sensitive circuit and what was messing me up was a single loop in my probe wire.
@@Mandragara Done that before and it's annoying!
I think you could also just look at the inrush current vs the steady state current.
When I was in grade 6 I kept asking the teacher when we did our introduction to electricity unit "but how does the electricity know what's ahead of it, how does it decide where to go?" I like that you decided to cover this subject a lot, I have a better understanding now but you always make very informative and entertaining videos. I kind of thought I knew the answer when I started thinking of electricity like water and that made a lot more sense to me but I'm excited to see the video and see if I can get a more comrpehensive understanding.
This is why I have the notifications turned on for this channel from day one, I have been pontificating the particles/waves,, Thank you and keep up the great work, I can see this channel reaching 1M+ soon!
Years back I majored in mechanical engineering and I still remember how much the fluid dynamics course blew my mind. When I learned how well everything in FD had a near perfect analog with electrical circuits it felt like things finally clicked in my head. Instead of living in a world with a near infinite amount of things all following their own principals and laws, most everything was more or less just different forms of the same fundamental objects and mostly seem to follow a relatively small and simple list of principals. It gives me hope that one day we may end up finding solutions to things like quantum gravity and the rules aren't as different as they look right now with our limited understanding.
And thermal, and dynamics, the analogies abound. But they are NEVER perfect, they always fall completely apart at some level. I used to like to think of capacitors like buckets, inductors like flywheels, voltage and current like pressure travel and flow in a rigid pipe, etc. Like I said, everywhere. My old man, at the start of his career, used to design analog circuits to simulate missile or helicopter blade dynamics, bending moments, stability and such. And yeah, fluids was a fun, but not super easy course...compared to Dynamics though, it was fairly easy, at least for me. My dynamics prof, first day, walked in and said F is ma, you can go home now. Right, and then soon we were into Coriolis, etc. He also said he'd keep the numbers reasonable, so if you calculated the weight of a guy in an elevator to be three tons, you did something wrong. There was a big hint there. :-)
@@MrJdseniorlangdown bridge gang to bridge mathematics to the realm of applied science
I took fluid dynamics my senior year studying electrical engineering. The professor -- who was dean of engineering -- told us EE students could sleep through the fluid circuit stuff.
He wasn't far off. I spent the time trying to think of fluid analogies for capacitors, inductors, and transistors...
Read the book: Principia Mathematica 2: A Complete Toolkit for Hacking the Physical Universe, by Robert and David Dehister.
They have a physical model of the matter-in-motion expressed with simple principles. They are able to describe electricity, gravity, light and magnetism in a simple manner.
And then quantum physics joined the chat
I have a technical degree in electricity and took several circuits and electronics classes for a Computer Engineering degree. This one single video explained how electricity works and answered questions I've been trying wrap my head arouns for years. In 20 minutes. Bravo. Thank you so much, and I look forward to your future videos explaining electricity using water that you mentioned.
hahahhaa same and we took the same course too
Been working with electronics at the hobby level for years, and this has always been something I *know*, but never intuitively understood. One demonstration and everything immediately clicked into place.
Love it, good work man!
I'm was an electrical engineer and I can safely say that your channel is the best explainer of how electricity behaves out there. Bravo, keep it up. I've binged your videos
You never miss man. Always very interesting and thought provoking content.
🎯
I am falling further and further down the rabbit hole of the scientific side of youtube and I am nothing but hyped for the journey.
Thank you for having incredibly simplified yet also complex descriptions and explanations. It ensures my attention is held no matter what level of understanding I have at the moment.
Amazing content. Thank you.
Welcome! Science youtube is best youtube. Hope you find something that inspires you to experiment/try/make stuff yourself!
@@skootz24 I've been stuck. Help 😂😂😂
ua he's incredible eh. why does YT keep showing me ther same recomendations
Hope you have seen Huygens Optics
man I wanted today to learn about antennas and im in EM waves, magnetism and electricity rbithole for last 8 hours... 4;30 am and I should sleep already
a great thing i like about your video is, unlike most others who wait till the very end of a 500 hour video before telling you the result-which makes viewers feel like getting tricked into helping monetize the video-it shows you the summary and actual secret right at the beginning, and shows in depth processes in the rest of video.
I've recently started working with circuits and it's really interesting how this "self-balancing" mechanism translates to the simple rules we were explained in class
Those 5ns riples are reflections in your maze. Touching the wire is producing diraque pulse which is propagated thru your maze. Every end or blind end will reflect that pulse back to source which depends on impedance. Add capacitance, inductance and resistance to your theoretical model and you will get your voltage readings on your scope. You can even do FFT of your response curve and you will find out that there are certain frequencies peaking up. Those are based on length of each branch in your maze. Each branch is now also a peace of tuned RF antenna. And remember, electrons are very slow in conductive material, the interaction between the electrons and overall propagation are what is almost as fast as light in vacuum.
Also, remember as electrons pass a gap they WILL generate RF. That's how RADAR and Klystrons works essentially. That maze is probably noisy as all get out in the RF spectrum.
" diraque " will say that or tell you, in french?
I'm glad I'm not the only one that thinks in rf! 😂
@@PigeonLaughter01 You say RF, I say black magic. Then again, the difference between a Computer Engineer and an Electrical Engineer is I didn't have to take Emag.
You probably meant Dirac pulse, and in that case a step pulse would be more accurate, dirac is short singular impulse
Love this channel. As a corrosion specialist who works on pipelines, i.e. cathodic protection, ac powerline interference, materials engineering, etc, i think this channel might be my favorite. I really like how excited you get about the science. Awesome job.
Nice demonstration! It always delights me when someone takes precious time to describe complex things in a simple way, thank you.
The whole maze/path setup is a perfect example of sheet resistance, too.
What a beautiful video. You tied together several high and low-level concepts of electromagnetism and with wonderful visual examples that are easy to parse quickly. Great work, I truly enjoyed this!
I love the water example. I don't see it as the input "pushing" the stream through the maze but rather the output "pulling" the water through a predefined path. As if you pull a string through the maze solution.
In reality it’s both! Mhedi made a great point like this in his video with Derek - you’re pulling on one end of the chain and pushing on the the other end of the chain at the same time - both actions deliver torque to the sprocket
@@AlphaPhoenixChannel See how if you have a barrel of water, a hose and a pump - you can put that pump at the end of the hose with the hose on it's inlet and other end in the water and it will suck the water from the barrel. Is there an electrical equivalent for that? It's negative pressure when you're 'sucking' water - is there some sort of negative electrical pressure
too?
@@alflud There is! Conductors like to be neutral, so if you pull electrons out of a conductor, other electrons will be drawn in from anywhere they are available. In reality, it's not a vacuum of electrons, but a charge imbalance, because when you remove electrons you don't remove the associated positively charged nuclei, and that section of the material gets a NET positive charge. That net positive charge and the associated fields attract more negatively charged electrons. Hope that made sense
@@alflud Yes, the cathode repels electrons while the anode attracts electrons so its like a pump pushing water at one end while "sucking" water at the other.
@@wayneyadams It's kind of both at the same time, but really a circuit is just that, a round circuit of wire that has to connect back on itself, a loop. In that sense, the pump is really what the battery is doing.
I love the water model for electricity! It's what really solidified my understanding of fundamental electronics. Looking forward to the (hopefully) coming video :)
I'm an electronics engineer and I thought of the electromagnetics of the foil maze which I understand quite well, and that actually gave me insight into the water maze haha
@@__dm__ When obsessing electronics students, it is always a good sign when they start to use electricity as a model for water system.
Really funny when the physic instructor tries to explain electricity with water models to EE students and they apply the tabels in reverse, because electricity becomes more intuitive then water after solving various resistors networks in Electrical Engeering Classes.
@@sarowie We treat heat transfer as energy flow through a resistive system when modeling it mathematically as well.
Spoke about this just the other day to a friend and here’s the video I recommended to them in my feed again waiting to be rewatched.
My guess for mazes with two solutions is that each path has some resistance R1 or R2. Given a uniform material, any one length of material in one path will have the same resistance as the same length in the other path. So the resistances are proportional to the length of the path. The current will split such that is split between the two in the ratio R1 to R2. So the less resistant path will see more current. The power dissipation is P = U * I. The voltage drop across both resistors is the same because they are connected, so the shorter path with more current will heat up more.
The maze with two paths is equivalent to two resistors in parallel, which is grade 5 physics textbook stuff.
Great video as usual. Two things I would have liked to see: 1. When you poured clear water onto the maze but kept pumping dyed water it would have highlighted the solution very nicely. 2. Multi-path water mazes. Maybe starting with clear water flowing and adding a dye tablet in the source basin would have yielded different strengths of colour in the two paths.
I bet you wrote this before watching until the end
I think with adding dye to a multiple-path water maze, they would both end up the same color, but the dye color would propagate more quickly through the shorter path due to the faster-flowing water.
Your multi-path experiment reminds me of a similar idea I had many, many years ago when I was much younger. Way before GPS was a thing I drove a cab for a couple of years. Routes driven were highly subjective and may or may not have been optimal but paper maps helped in many cases. My idea was to create a road map using lengths of wire to represent streets and each intersection would be the relevant wires joined at the junction. At the mid-point of each street between intersections, there would be a small bulb that would light when the current passed that point. One-way streets would be controlled by diodes in the circuit and in an improved version, speed limits would be controlled with resistors in the circuits. The ultimate thought was that probes would be clipped onto the starting and ending points, and a string of lights would show the shortest (and quickest) path to take. I never got to a testing stage with the idea which is just as well since the covered area of 750 square miles had over a thousand streets covering over 500 miles and probably a dozen or more ways to get from point A to B. The resulting map would be totally unmanageable in size and either all the bulbs would light or, more likely, none would be bright enough to see.
This has opened up a whole new level of intuition for me about voltages, resistance and current flow. As an electronics student I had already worked out one way of thinking about these things, but to see voltage as a change in "height" has finally satisfied my question of what potentials really were. In a uniform gravitational field, height is equal to the potential energy per unit mass and likewise electrical potential is the potential energy per unit charge. Also very interesting to work with wires of roughly uniform resistance like this - makes the current flow much more intuitive than with wires with almost zero resistance connecting components with a much higher resistance proportionally. Thanks Brian, for explaining things in the way that only someone with a good understanding can! Have a good one :)
I think it's a useful analogy to view voltage as pressure and current as flow.
Showing how hard it is to measure transients on the order of a few nano seconds is such a contribution to viewers! It's a very valuable practical lesson in many ways. It is made all the more effective with the high spirits you keep as you fail to get a conclusive measurement.
Respectable work!
I was not a "physics" person in school and I absolutely love your videos! Thank you so much for sharing these with those of us who "didnt get it" in school!
this just gave me a great idea for a D&D scenario. The players find themselves in a dungeon maze and there's an aqueduct near the entrance. Maybe there's already a leak in the aqueduct with a little stream running down into the dungeon and some wood barrels near the entrance to give the players a hint on how to solve it.
Great video, just a couple recommendations:
1) What about glueing the mazes to some kind of base to avoid annoying perturbations in your tests?
2) As a cheaper alternative to lasser cutting... you can use conductive 3D printer filment instead 😊.
Thanks for the interesting video!
I've loved watching your channel grow. From all your subscribers to your Ph. D., I just wanted to say "Congratulations!" Thank you for all of the wonderful content!
I love this. I had a hard time visualizing and understanding electricity as a student until I started using water as an analogue - great experiment.
First (but not the last) time watching this channel. Much more depth, creativity and passion than I was expecting. Nice work!
couldn't agree more instant subbed
Awesome video! The way you explained it is so intuitive and easy to understand with examples and refering back to simple concepts. I wish I had this back when I first learnt about electricity
Bro, I'm just gonna say it, you're awesome
Agreed!
Holy carp you actually said it m8
Electrical engineering was always my weakest point, I'm always glad when you make videos about it. Excited for the eventual hydraulic analogy one.
"how does current find the 'path of least resistance' " is something I've honestly questioned for a very long time (but was too lazy to do real research lol) thank you so much for laying out the perfect answer so clearly!
The answer is it doesn't, you caught that right?
So cool how you referenced two videos I previously watched. Using the water maze horizontally was even better.
Wow, that was a lot of work but it was definitely worth it because this demonstration was every bit entertaining as it was educating. Really nice explanation of everything.
While watching this I had three thoughts. 1. After a four year physics degree, I think I would prefer to have had Alpha Phoenix as my high school teacher, than my university lecturer. Your ability to take complex and even controversial topics and make them accessible is fantastic and all young people should watch your work. 2. I am quite obsessed by super-high time-resolution photography of stepped leaders. Obviously an oscilloscope is going to have trouble seeing the EM fields, feeling their way around a maze. But perhaps a huge maze with atomic clocks scattered around could allow us to see the equivalent of stepped leaders in an electrical circuit? 3. In the very last pictures, why does the circuitry heat up so much more, at the corners of the maze? I get how, for example, racing cars have friction when they get to the corner. But how do EM fields or electrons know to expend more energy at the corners of a maze? I am fascinated by that picture!
that's what he asked but you like me already agreee with his posit thus already assumed to equiv to water flow.
You always put so much effort into explaining things simply. Really love your videos.
I'm sure someone else said it in the 1000+ comments, but that last demonstration was also a good explanation of why an inadvertent low-resistance path is called a "short circuit" and why it's a problem.
This is an awesome visualization! It also makes the formulas and calculations in electronics more logical to me. In the end, all electronic circuits are basically just a maze, where the measure of resistance of a certain component tells you how "long" that component's "path" is, and the voltage drop over a series of components gives you the "gradient" of the "water hill"
WOW.. I've been torturing electrons for over 40 years and have never seen such a great demonstration. Nice Job!
A good way to think about it is that once the shortest path has been found, it's like a pulling motion from the end of the maze, rather than a pushing motion from the beginning. Now the water is being pulled through the maze from the end of the maze, so it's always following that path (despite very small deviations here and there).
That's a way to _think_ about it, but it does not correctly portray a solution. The solution is in the video, and it is not in theoretical equivalence with any pulling mechanism.
Yes it's theoretically equivalent to think about it this way, the pressure differentials along the path are what define this behavior, and that two-way equilibrium is only established once the path has been located. The added tugging force (pulling motion/negative pressure) is what allows for this path to dominate over the other paths. Without it, as you can see when the maze is closed, or when it hasn't located the path yet, there is nothing to enforce that particular path. So it is more clear to think about this from the opposite end once the path has been established, as this is what is maintains that behavior. It works the same way with the electricity example as well, negative and positive EM radiation pressure. @@-danR
Btw, the "solution" (it's not a solution) is wrong. This is not caused by water level, that is just an observational byproduct. You can read his pinned post that confirms this as well if you need to appeal to an authority.
Instead of pulling, I like to think about it like the electrons get out of the way. Imagine rolling a basketball down a highway of AI driven cars (all going the same speed). The ball will follow the path of least resistance.
I'm guessing that the electricity will treat each valid path like a parallel resistor. A larger portion of the total current will pass through the shorter path.
Excellent demonstration of the concept of why trying to increase capacity of wires by adding separate wires is fraught with problems, and yet it works when people do manage to run equal lengths in their DIY setups
Dude, you're such a great engineer/physicist/educator. Amazes me every single time!
Do I ever struggle to solve mazes, you ask? Yes, I have indeed played The Witness…
The electrons in current move extremely slow, but electrons are tiny and their force is strong. Through the entire life of a power plant, the electrons in the main conduit may never leave the premises, but they force other electrons to move, which force other electrons to move, and can move electrons hundreds of miles away
So following the water analogy, the flow of "current" is the gradient of the pressure of the water in maze. (Actual hydro-engineer or physicist correct me.)
From high school physics, the elections themselves move down a wire about as fast as the hour hand of a clock. It's slow on our scale, but not overwhelmingly so.
1:13 this man, sitting with a casual 2.4 Amps of current running through his maze there
This was a great video. A slightly more technical way to put it that is also helpful is that all conductive material, including wires, have capacitance. A capacitor is like an electric spring, same equations as a spring. Compressing the electric spring is the same thing as the filling up of the maze with water. When the voltage is removed, they will "slosh" out, or sort of pushed out like a spring releasing compression, as the charge of the maze reaches 0 again. I always found the spring analogy helpful.
Thank you Norway for inventing this techonology and spreading it to the world.
aMAZEing
Ba dum tss
Id be curious to see if the path for those multipath mazes changes if you changed the cross section area of the foil at different points. Id expect thinner parts to maybe act like resistors. If that was the case it would still make sense with using water as an analogy for electricity.
Yup! A thinner path would behave like a longer path, and it IS still very well-represented by the water height=voltage shtick! I shoulda done that…
Actually come to think of it I kinda did with water! For the 2-path water demo, I had one that was printed the same width as the maze channels and it wasn’t dropping enough voltage -I mean height- so I thinned the channels to 2mm wide 😁
This would be interesting to see. I understand that the paths for current are acting like resistors and longer paths lead to higher resistance. I also get that thinner paths have higher resistance. Would be interesting to see the pattern of a solid sheet of foil.
The part that is confusing to me is the real world application. From soldering simple analogue circuits, the gauge of wires or traces doesn't really seem to make any difference, I guess since the scale is so far off from the resistor components etc.
Thanks for the videos and comments!
@Robert Swaine A weir is indeed weird
It completely blocks flow under a certain threshold, and once over that threshold its resistance goes down as potential goes up.
What electronic doohickey does the same?
@@Hirosjimma Zener diodes, particularly a pair of reversed Zener diodes in series?
@@Hirosjimma I think what's really going on is in a Forward bias situation you get an exponential relationship between voltage and current. But when you're in a reverse bias you get a really small current until you surpass the breakdown voltage. I think it's also good to represent that in terms of current and voltage because diodes are typically shown in terms of their IV curves (current vs voltage). Just like how a diode behaves, the band structure even looks almost the same as the physical weir. But also like the weir and a diode, you need a small forward bias to go down the weir, but a large reverse bias to go the other way, until you get to the breakdown voltage.
0:12 no i dont, goodbye
Thanks for the recommendation on how to solve mazes. This is so much easier than any other possible method!
Thank you for correcting the common misstatement, "electricity follows the path of least resistance." In fact, the current flowing in each circuit corresponds indirectly to its resistance, but current will flow in all available paths.
Awww the maze, my favorite medium of simplicity to be able to find solutions. Such beautiful plain medium 😊
Man, I love this channel! Love the channel name, logo, subtitle combined with channel name...all of it!
22:07 Just after you made the "snip", on the other path, the heat builds up around the bends first, while the straights are cool. Fascinating.
We use the saying...."path of least impedance" at work. It's a good way to always remember that a lot of devices or circuits use both AC and DC and it reminds you that capacitive reactance and inductive reactance can play be huge factors in how that circuit operates.
Honestly this is how voltage should be demonstrated. It’s so much easier when you use examples involving more paths than explaining voltage with a single path (like a lot of demonstrations do).
Im a 22 yo going into my senior year in ME and I genuinely feel like I learn more watching this guy while im drunk than going to class.
Great video and great explanation. I like that you say the electricity is taking both paths. The phrase "electricity takes the path of least resistance" implies that it does not take other paths of more resistance. If this was true then each power plant could only turn on one light bulb, the brightest one. Electricity takes every path it can.
I love the vocabulary that you use. It mixes will with what you're trying to describe. Maybe you're just that good. Maybe we're just similar. Whatever the case, I enjoy your videos A LOT!
Very nice experiment! It illustrates Kirchhoff's circuit laws in an interesting and engaging way. The different paths to "solve" the labyrinth are wires of different lengths and can be seen as resistances of different values. For two resistors in parallel, more intensity will flow through the least resistant one and so it will heat up more.
I literally don’t know what to say. This was so much of an incredibly instructive video…
Thank you so much for the point about anthropmorphizing systems and giving the real system. Past Me from highschool was continuously so frustrated by teachers in science classes saying a beaker of chemicals wants to be in a lower energy state with no further explanation. Or any of a thousand other examples. It's a useful shorthand, but it's important to peel back that layer of abstraction and figure out *why* a system "wants"' anything.
Wow! This might be quite literally one of the COOLEST things I've ever seen!!! THANKS!!!!
VERY cool visual representation of what's happening!
Absolutely fascinating. I understood most of this already, but you've helped me visualize it in an entirely new way. Only 8 mins in, but already I can see how resistance is essentially drag created on the "electron water" and an item being conductive basically just means the water in the maze is already filled (the way electrons are already in the material and don't ACTUALLY flow like water)
So basically I'm assuming that by the very nature of how resistance works, plus the 'gravity' model of the flow finding the path, the fact that resistance even exists is what actually allows electricity to follow the path, as it is basically testing all paths at the same time, but only the path with an output can 'move' and this 'low pressure zone' creates a metaphorical vacuum that then creates the flow of electrons.
This is my favourite vid of the year, thank you so much! (I'm gonna keep watching now, I assume there is plenty more to learn)
cutting the wire at the end was somehow both surprising and completely understandable. At first I interpreted as the flow getting trapped in the bends (and promptly realized how silly that was) and then realized this is heat, not actual flow, and the corners will have the highest concentration of heat due to the proximity to other areas of the 'wire'. But it did also highlight the flow, in that because the metal heated up SO much slower than the electricity flowed, you can actually still see (from top to bottom) that it is filling in as it goes from start to finish.
Yep, absolutely fascinating and a really beautiful illustration that truly cemented the concept in an accessible way. Great work!
Thank you very much for all that you demoed. This has been huge to my understanding of circuits.
11:50 This is 'ringing' because of different impedances of generator, oscilloscope and the maze. It happens with a long wire (without maze), too.
EE approved! What a great metaphor and visualization to help people learn electricity intuitively!
It was really cool to see a practical demonstration of this, and the explanation was really easy to follow. Great stuff!
22:18 was the lightbulb moment for me. Great explanation.
Man, I know water can be used as an analogy for electricity but this is on another level.
1:43 awesome quotable line
5:10-5:30 I REALLY liked this part.
8:00 boy, that's a lot of systems.
15:38 this is a very good defense of the water explanation for electricity.
20:08 it feels like ideas work this same way.
22:14 this is really satisfying
i really wanted to see the last maze in water.... you gave my brain an itch.. thank you.
Awesome analog. The "instantaneous" speed at which the electrons flow, sounds like a challenge you should throw down to the Slo-Mo Guys to see how the IR response looks.
Thanks, man, for sharing.
Great video loved the callbacks to Grady and Steve's uploads, other great channels covering theory with helpful practical examples. Loved thoughts being confirmed by the excel visualization. Had a jump saying "back to equilibrium" out loud then thinking maybe that wasn't the right word and was immediately followed up by the video saying it too
This video is not only interesting, but kind of fun as hell. I would have gone gaga over this if I'd seen it at 10 years of age. Great work!
Absolutely fantastic work ! You are teaching and creating true deep interest in science, Something we really need today more than ever. If I was wealthy, I would fund you for 20 years of experiments. Thank you so much.
Now that is a surprisingly interesting and intriguing information! Never really got an explanation of how electricity finds the path of least resistance. Very interesting
first time seeing this channel and i subscribed immediately after seeing the intro.
he didn't beg, he earned it
I thought the same many times. And then 1 day i realise current is not flow to the shortest path. Current always flow with least resistance. And after watched your video I confirm. Thanks man 🎉🎉
For Example if we have two types of wires first wire is 1 meter long and other one is 10 metre long but has 10 times less resistance compared to first one then the current flow on the both wires is same . If you read my comment please reply me if i was right 👍
Resistors in parallel ...
No way man, was thinking about this last night but never searched it on web and today its the first video recommended.
Amaizing, and what is even more amazing is how mathematics and physics describe nature.
I love that we both had the same reaction when you cut the 4th maze.
Thanks so much for such a great video. It really makes sense now how electricity follows the least resistance path, It's not because it always knew where to go but because it "test" all the paths! And choose the one that takes the less effort to complete. You just won a new subscription!
Wow this is normally the kind of questions I come up with, this is explained SO well. Nice one.
These explanations were better than those of any professor that I had.