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Why is electricity so hard to understand? (1989)

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Re: Why is electricity so hard to understand? (1989)

#31

Post by johncolanduoni »

tim333 wrote: post #10
pjc50 wrote: post #7

Earlier quoted context omitted.

Like QM, doing it analytically clears away misconceptions and gives a consistent view - but it isn't exactly something you can teach to children. It's useful to be able to explain things to laypeople and the not mathematically inclined, which means tightening up the metaphors.

Also Maxwell's equations only give you part of it - for the question of why an atom's electrons don't just fall into the nucleus you need QM. And then you get into the self energy of the electron which is not explained by any present physics ( http://www.feynmanlectures.caltech.edu/II_28.html ). So you can't just do the math because we don't have all the math.

For electrical phenomena (baring very very small scale, semiconductors) Maxwell's equations give you a huge amount of insight, especially the macroscopic variant. You can see things like plasmons and polaritons (though obviously not their quantization).

You won't really run into the atom stuff until you try to do something like calculate dielectric constants analytically, though self-energy is definitely a pretty easy trap to fall in even for macroscopic stuff.

Re: Why is electricity so hard to understand? (1989)

#32

Post by k__ »

selimthegrim wrote: post #25
k__ wrote: post #24

Earlier quoted context omitted.

I got it taught about 3 or 4 times, and every time I understood it less. In middle school they told me, it's electrons moving at the speed of light through a conductor. In high school they told me, no no, they don't move at the speed of light, just when one electron enters the conductor, another one on the other side will leave the conductor, like with peas in a straw. And this enter/leaf is at the speed of light. At…

Well someone fucked you up because current is defined as the flow of positive charges just like the electric field direction is defined as the action of a positive test charge. Thanks Ben (Franklin)

lol, seems to be.

I read a few articles on that page and it's like magic, it makes not much sens to me after all I learned at school.

Re: Why is electricity so hard to understand? (1989)

#33

Post by agumonkey »

k__ wrote: post #24
notalaser wrote: post #16

I think more than half the time I spent earning my EE degree has been spent unlearning the intuitive (but wrong) things that I was liberally taught. I was fortunate enough to have an exceptional Physics teacher in high school, who managed to avoid a lot of the bullshit that less fortunate students were fed; sadly, I compensated that with some of my own (misguided) self-study. This experience also taught me to activel…

I got it taught about 3 or 4 times, and every time I understood it less. In middle school they told me, it's electrons moving at the speed of light through a conductor. In high school they told me, no no, they don't move at the speed of light, just when one electron enters the conductor, another one on the other side will leave the conductor, like with peas in a straw. And this enter/leaf is at the speed of light. At…

I start to think that the less you make sense of a topic, the closer you are from real understanding.

ps: this comes from years of self learning music, every now and then my incomplete abilities go through a complete crash, only to reveal a critical misunderstanding, lack of sensitivity in my perception or action, that leads to a sudden and very blissful resolution (your own private eureka moment)

Re: Why is electricity so hard to understand? (1989)

#35

Post by justifier »

notalaser wrote: post #16

I think more than half the time I spent earning my EE degree has been spent unlearning the intuitive (but wrong) things that I was liberally taught. I was fortunate enough to have an exceptional Physics teacher in high school, who managed to avoid a lot of the bullshit that less fortunate students were fed; sadly, I compensated that with some of my own (misguided) self-study. This experience also taught me to activel…

From the linked notes:

I never really understood capacitors until I started trying to construct proper water-analogies for them. Then I discovered that my electronics and physics classes had sent me down a dead-end path with their garbage about "capacitors store electric charge." Since my discovery, I've gained significantly more expertise in circuit design, which leads me to a sad thought. Maybe the more skilled of electrical engineers and scientists gain their extreme expertise not through classroom learning. Instead they gain expertise in spite of our K-12 classroom learning. Maybe the experts are experts only because they have fought free of the wrong parts of grade school science, while the rest of us are still living under the yoke of the many physics misconceptions we were carefully taught in early grades.

http://amasci.com/emotor/cap1.html

Re: Why is electricity so hard to understand? (1989)

#38

Post by soneca »

It looks like interesting content, but I got a little confused by the writing style and general layout.

A more succinct, clearly defined structure would help me a lot. Each topic could be clearer on what is wrong and how is the right way.

It would help a lot just to start with a clear: "What is the right definition of the word electricity?". Then, maybe a "What is "electrical phenomena" and some examples". "Correct definition and differences of electric charge, energy and current".

For me personally, a structure that explains what is the right thing first, then goes on about misconceptions and consequence of misconceptions is much better.

I became lost while reading this and finished with basically the same confused and mistaken understanding of what is electricity as I began.

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