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# How does current electricity REALLY work? watch

1. Essentially, please explain to me how current electricity works, namely how energy is actually transferred to in the circuit components, but also about potential difference and electric fields present in a circuit.
The way that current electricity has been simplified for easier understanding at GCSE and AS level has just confused me and is clearly just meant to be just enough for you to be able to pass your exams.
It's easy to sit for 5 minutes and pick holes in the simplification, which just destroys any confidence I have in my understanding of the material.
I'm talking about the "Oh, the battery gives the electrons energy, which then move to the components and when they reach them they give the components energy" and then in the next breath "the electrons actually have a really slow drift velocity" making the previous statement obviously false by how quickly a light turns on when connected to a powerpack (the even more obvious flaw is of course the fact that AC currents actually work at all).
I've asked my teacher about it and either she can't or won't give me an answer, for whatever reason.
I have learnt the A-level content on electric fields to try to understand this, but still can't.
Maybe there is a really simple way to understand it, or maybe it requires undergrad level understanding - if the latter is true and it cannot be explained in a single TSR post, then please link me some resources which will allow me to understand it.
Note: Unless necessary, I'm not talking about learning about super complicated aspects of circuits, I'm just talking about the basic understanding of how they actually work - something which seems not to be taught properly at GCSE or A-level, for whatever reason.
I appreciate all help!

P.S. If you can help me understand this you are literally my new Messiah and I will love you forever.
2. (Original post by PhysicsIsUs)
Essentially, please explain to me how current electricity works, namely how energy is actually transferred to in the circuit components, but also about potential difference and electric fields present in a circuit.
The way that current electricity has been simplified for easier understanding at GCSE and AS level has just confused me and is clearly just meant to be just enough for you to be able to pass your exams.
It's easy to sit for 5 minutes and pick holes in the simplification, which just destroys any confidence I have in my understanding of the material.
I'm talking about the "Oh, the battery gives the electrons energy, which then move to the components and when they reach them they give the components energy" and then in the next breath "the electrons actually have a really slow drift velocity" making the previous statement obviously false by how quickly a light turns on when connected to a powerpack (the even more obvious flaw is of course the fact that AC currents actually work at all).
I've asked my teacher about it and either she can't or won't give me an answer, for whatever reason.
I have learnt the A-level content on electric fields to try to understand this, but still can't.
Maybe there is a really simple way to understand it, or maybe it requires undergrad level understanding - if the latter is true and it cannot be explained in a single TSR post, then please link me some resources which will allow me to understand it.
Note: Unless necessary, I'm not talking about learning about super complicated aspects of circuits, I'm just talking about the basic understanding of how they actually work - something which seems not to be taught properly at GCSE or A-level, for whatever reason.
I appreciate all help!
Hi,

I am sorry for the late reply and hope the following writing and reference(s) helps. I am glad that you ask this question.

http://amasci.com/elect/poynt/poynt.html

The above reference (I believe) would help you “understand” the transfer of energy from a battery to an electrical component like a light bulb via Poynting Vector of an electromagnetic field. There are other references at the bottom of the above website which would give the details of what is lacking in the website. You may want to learn what is a Poynting Vector of an electromagnetic field.

https://en.wikipedia.org/wiki/Poynting_vector

I would give a “short and over-simplified” summary of what is going on.

The battery maintains a charge separation on the two terminals. When two “ideal” wires and a resistor (or light bulb) are connected to the battery to make a complete circuit, surface charges are spreading out all over the circuit within very short time. A varying surface charge distribution creates an internal electric field inside the wire and an electric current starts to flow. The surface charges also produce a component of the electric field that is perpendicular to the surface of the wire. The currents also “give rise to” magnetic fields around the wire. It is the combination of electric field and magnetic field in the space outside the wires that transfer the energy from battery to resistor (or light bulb) via Poynting Vector of an electromagnetic field (see fig 7 in the website).

I would “try” to provide an “answer” why this is NOT properly taught in GCSE or A-level. There are not many resources (I mean printed common physics texts) that explain this and I believe that not many physics GCSE or A level teachers were really taught of the correct physics of such things in the last century. The movement of teaching the development of surface charge on the wire in a closed circuit is slow and seems to take place in the last decade after Jackson published an interesting paper on the surface charge in 1996 and a new undergraduate physics text known as Matter and Interactions by Chabay and Sherwood was published. This text is very different from traditional physics text. More published papers and physics texts are appearing to discuss how to understand the development of surface charges in the last decade and current decade.

A lot of school physics teachers are still relying on water pump analogy to teach current of electricity which I believe is also the cause of not teaching the understanding of current of electricity properly. Some physics teachers and common physics texts authors don’t really understand what an analogy does and misuse them to introduce a lot of confusions or misconceptions for this topic (current of electricity).

Hope this makes senses to you.
3. http://www.furryelephant.com/content...ynting-vector/
I just came across this website and I think they did a job in explaining the what you are asking.
4. (Original post by Eimmanuel)
Hi,

I am sorry for the late reply and hope the following writing and reference(s) helps. I am glad that you ask this question.

http://amasci.com/elect/poynt/poynt.html

The above reference (I believe) would help you “understand” the transfer of energy from a battery to an electrical component like a light bulb via Poynting Vector of an electromagnetic field. There are other references at the bottom of the above website which would give the details of what is lacking in the website. You may want to learn what is a Poynting Vector of an electromagnetic field.

https://en.wikipedia.org/wiki/Poynting_vector

I would give a “short and over-simplified” summary of what is going on.

The battery maintains a charge separation on the two terminals. When two “ideal” wires and a resistor (or light bulb) are connected to the battery to make a complete circuit, surface charges are spreading out all over the circuit within very short time. A varying surface charge distribution creates an internal electric field inside the wire and an electric current starts to flow. The surface charges also produce a component of the electric field that is perpendicular to the surface of the wire. The currents also “give rise to” magnetic fields around the wire. It is the combination of electric field and magnetic field in the space outside the wires that transfer the energy from battery to resistor (or light bulb) via Poynting Vector of an electromagnetic field (see fig 7 in the website).

I would “try” to provide an “answer” why this is NOT properly taught in GCSE or A-level. There are not many resources (I mean printed common physics texts) that explain this and I believe that not many physics GCSE or A level teachers were really taught of the correct physics of such things in the last century. The movement of teaching the development of surface charge on the wire in a closed circuit is slow and seems to take place in the last decade after Jackson published an interesting paper on the surface charge in 1996 and a new undergraduate physics text known as Matter and Interactions by Chabay and Sherwood was published. This text is very different from traditional physics text. More published papers and physics texts are appearing to discuss how to understand the development of surface charges in the last decade and current decade.

A lot of school physics teachers are still relying on water pump analogy to teach current of electricity which I believe is also the cause of not teaching the understanding of current of electricity properly. Some physics teachers and common physics texts authors don’t really understand what an analogy does and misuse them to introduce a lot of confusions or misconceptions for this topic (current of electricity).

Hope this makes senses to you.
Thank you very very very very very very very very very very very very much.
This is exactly what I was looking for and has made me very happy.
Thank you very much again.
Have a wonderful year!

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