Circuit Energy doesn't FLOW the way you THINK!

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.
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VIDEO ANNOTATIONS/CARDS

Does Electricity REALLY Flow?

What the HECK are Magnets?

You Do NOT "Charge" A Battery!

What the HECK is Energy?
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LINKS TO COMMENTS

Alternating Current:

TURN DOWN FOR WATT?!

Perpetual Motion:
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IMAGE CREDITS

John Henry Poynting:

Ben Franklin:

JJ Thomson:

[ScienceAsylum]

I seem to have made _educational_ choices in this video that some viewers feel are mistakes. They are not mistakes, but I’d like to take a moment to clarify so you can understand why I made them.


2. I’m aware that the directions of my vectors are not _perfect._ As I said in point #1, materials fall on a spectrum. The direction of the electric field and, therefore, the direction of the Poynting vector depends on how conductive the material is. While that detail is true, it isn’t actually _important_ to understand what’s happening with the energy in the circuit. For clarity, I chose to omit some components of the vector because they distract from the main take-away of this video: *The energy flows through the fields, not the wires.* I stand by this decision.

3. At 5:15, I say “we’ve got a strong electric field inside” the wire “and a little electric field outside.” Strong and little are a very relative words. Broadly speaking, _all_ the fields we’re dealing with in this video are _weak._ However, in the context of the circuit, what matters is how those fields compare _only to each other._ The electric field inside the wire might be weak, but it’s stronger than the electric field outside. Maybe I should have said “stronger” instead “strong, ” but I don’t really think that’s worth getting upset about.

4. Speaking of field strengths, yes, I’m aware the field is _strongest_ at the surface of the wire. Is the surface of the wire not part of the wire? I’m not sure how this negates anything I said in this video. In fact, that statement is completely consistent with my electric current animations in the video I linked to in point #1.

[kyungtak]

I'm PhD student in physics and I already knew about Poynting vector and its applications on Maxwell's equations
But I've never thought about energy flow on the circuit. That was truly mind-blowing.

[slappy]

Ben Franklin said that Amber becomes negative when rubbed? Maybe she just wasn't into him.

[haushofer]

I did a PhD in string theory/quantum gravity and teach physics for 3 years now. Only this week I learned how energy is transferred exactly in a curcuit. These videos are amazing. Many thanks.

[michaeleric]

Veritasium brought me here... and at this video is where I was finally enlightened that flow of charges is NOT the same as flow of energy. Thank you, Nick, for this awesome educational video!

[SoManyDogs]

Came for a little light science. Left with entire view of the universe changed. Mind blown.

[derradfahrer]

As a physicist, I approve this message. Best explanation I have seen so on the internet so far.

[DavidFMayerPhD]

The hard part is accepting the fact that energy does NOT flow though the wire, but through the space AROUND the wire. This is another non-intuitive aspect of Physics.

[rationalthinker]

I am really glad I just randomly found your channel. I am a second year electrical engineering student and lots of your videos are giving me a more intuitive feel for things instead of just crunching numbers according to formulas. Great job.

[xyz.ijk.]

That was fantastic. And yes, my head exploded. I'm going to have to watch that 50 more times ... 20 of them just for the sheer Joy of it, 23 of them to understand it, and 7 because I like round numbers. Totally unimportant.

[dukenukem]

My mind is officially blown! I got my PhD in physics 10 years ago, and I do science for a living. I’ve never thought much about E&M though. I just took the one required class and I specialized in a field of physics that doesn’t deal with electromagnetism. This was an amazing video! Well done!

[anirbansarkar]

THIS is the way physics should be taught.

Why do people have to make it so dull? Teaching always stops with the equations, and then they ask us to solve problems with the equations.

Students should be taught how all this corresponds to reality. Great job on the video Nick, lot of effort put in to blow our minds. 😵

[MarshmallowRadiation]

Someone who knows nothing about electricity: "electricity is literally magic"
Someone who knows a little about electricity: "electricity isn't magic, it's science"
Someone who knows this about electricity: "electricity is literally magic, and we know this because it's science"

[sjzara]

This changed everything about my understanding of electrodynamics since I first learned about it in the 70s! Thank you for producing such a brilliant video.

[oliverwest]

I thought I had a good knowledge of electricity, but yet again you have blown my mind. Never stop making these quality videos, you have a talent for teaching.

[jimdahlen]

I worked for Atlantic City electric as a lineman, we were not taught this. We were told to think of it like a water hose. This is mind blowing for sure. Thank you for what you do

[mrDjuroman]

Years of studying electrical engineering, and I figure out what I'm actually learning in college from a youtube recommendation. Mind = blown

[DeclanMBrennan]

Best one yet. I have a degree in Electronic Engineering and I've never had a satisfactory explanation for this despite asking your very question about AC in college. A little moment of dizziness as my paradigm shifts and welcome to that joy when suddenly the pieces fit together a lot better. Thanks.

[NimbleBard]

I was curious after watching Veritasium's video about this. TWICE. But now I understand it after I watched your video. Thanks! And yeah, my jaw also dropped in awe :O
Now I'm off to Space Time's new video about black holes!
EDIT: on a side note, now I need a more precise quantum explanation of all of this xD
EDIT2: quite a discussion we have here :)

[chrisalvino]

This is quickly becoming one of my favorite science channels on YouTube!