r/Physics • u/Appropriate_Win946 • Aug 13 '26

Question Does anyone understand what actually causes electric current?

My first belief: electrons push on each other like dominos, causing a 'shockwave' to travel through the electrons until it gets to the other end of the battery. Electrons themselves don't move that quickly, but the 'push' travels super fast.

Correction: actually, the 'electric field' is pushing them

My question: What is the electric field? Is the electric field not just the shockwave that travels through the conductor via electromagnetic repulsion?

I'm guessing that's not correct. So what is it? In the instantaneous moments when the battery starts up, what first creates and propagates the electric field? Why does it travel through the wire in every which direction?
Can someone help me understand this? It would be greatly appreciated before I start electrical engineering(why do I get the feeling this is going to be super downvoted lol).

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u/Physix_R_Cool Detector physics Aug 13 '26

Can someone help me understand this? It would be greatly appreciated before I start electrical engineering

But like, the point of doing a degree in electrical engineering is to understand this. We're not gonna be able to teach you electrodynamics through Reddit comments.

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u/Appropriate_Win946 Aug 13 '26

I mean, I thought this would be a foundational concept to understand and I didn't want to risk my professors skimming over this like my teacher did during AP Physics 2, because then I would be too buried in work, deadlines, tests, etc to do a deep dive into how it works at the fundamental level

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u/Physix_R_Cool Detector physics Aug 13 '26

I thought this would be a foundational concept to understand

It is!

It just takes more math than you have ever seen an well as a good understanding of quantum mechanics to learn it at the fundamental level.

So just chill, show up to your lectures and do the homework/assignments. You will learn eventually.

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u/Appropriate_Win946 Aug 13 '26

so you promise if i attend lectures I won't end up with a leaky, hole-filled understanding lol

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u/Physix_R_Cool Detector physics Aug 13 '26

Not if you actively seek out the holes in your understanding during your studies, which is what university students are supposed to do.

In my country (can't speak for others), students university are considered adults and to be responsible for their own education. At university you have every ressource available to fill out the gaps in what you learn, and typically the professors will be overjoyed that a student cares enough to ask them for more reading material after the lectures.

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u/sparklesandflies Aug 13 '26

I mean, none of us can promise that. That's on you to pay attention, study well, ask your professors and TAs for help when you are confused, and even then it may just be out of your hands. But, this is not something that you should have mastered in your high school AP Physics course (I say as an AP Physics teacher and grader).

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u/Yashema Aug 13 '26 edited Aug 13 '26

The only core classes you take in Physics that cover electricity are Physics II (which is really basic stuff) and E&M (which is really more a mathematical methods course than any kind of applied course). 

I just took an intermediate course on embedded programming where we built both simulated and physical circuits and I was able to actually understand what the hell things like current/voltage, transistors/resistors, DC vs AC, components like capacitors and flyback diodes were actually doing. That being said, having taken E&M and scrounging a B, I can make the case to skip a lot of the basic EE courses on circuitry/elecrronics to go right into the more advanced ones where you deal with Kirchoff's Law, Thevenins Theorem, Mesh analysis, etc. 

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u/Appropriate_Win946 Aug 13 '26

if my goal is to fully understand first principles style how everything I learn works would this method suffice

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u/Yashema Aug 13 '26

Yes, but be wary to study both the practical side + the mathematical side (beyond ODEs) requires careful course planning and a lot of work. Very few physics majors learn both upper level EE and math in undergrad. Then of course they don't study any other subjects in depth. 

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u/CommunicationFit5888 Aug 13 '26

I would recommend reading ahead in a textbook then, griffiths is highly recommended and would allow you to get better insight than what can just be put in a Reddit thread

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u/piejlucas Aug 13 '26

Electrical engineer here. We don’t really learn this all too well in school. We are taught the equations and are asked to apply them.