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The misconception is that electrons carry potential energy around a complete conducting loop, transferring their energy to the load.
Based on the laws of electrodynamics, energy cannot flow in the same direction as the electric current. According to the Poynting vector, electric power will flow anywhere there is both an electric field and a magnetic field. The consequences may surprise you.
When charge moves, we call it electric current, but the word current is usually reserved for things like water flows. Does electric current really work like that? Electrons are quantum particles, so we have to be careful.
0:00 Veritasium?s question and answer, was he right?3:51 Short review of Derek?s video5:24 Poynting Vector, direction of power flow9:05 Detailed analysis of Derek?s question, Transmission Lines17:37 WATCH THIS PART!
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).
Dave analyses Veritasium's video "The Big Misconception About Electricity" and how energy flows in the Poynting vector in the electromagnetic field OUTSIDE the wire instead of inside the wire.00:00 - Veritasium's video "The Big Misconception About Electricity"00:32 - Rection to the points in the video01:11 - This is a bit MISLEADING!02:28 - Electron drift03:51 - Engineers use different tools and theorems04:27 - Every electrical engineer knows this05:17 - Everything he says is correct08:24 - What is current?09:30 - He doesn't address this in the video. Poynting vectors at DC11:12 - How the lightbulb works12:41 - At the physics level, it's correct14:11 - My only problem with this is...15:08 - Is it just an academic discussion?16:17 - The undersea cable is just early transmission line theory17:20 - So what is the answer to the question?22:06 - What about skin effect and DC?25:44 - Let's simulate this and answer the question29:18 - Transient analysis33:00 - DC Steady State analysis34:28 - The quantitative values don't matter38:25 - But what about DC steady state?40:24 - What does Richard Feynman think?
In this video I use the history of electricity to respectively disagree with Derek Muller's physics puzzle on what happens in a DC circuit.
In this video, I measure a wave of electricity traveling down a wire, and answer the question - how does electricity know where to go? How does "electricity" "decide" where electrons should be moving in wires, and how long does that process take? Spoiler alert - very fast!I've been very excited about this project for a while - it was a lot of work to figure out a reliable way to make these measurements, but I've learned SO much by actually watching waves travel down wires, and I hope you do too!