Energy

[reverendjeremiah]

Yes of course you're right with regards to AC, but what plumbing system works on the basis of the water flowing opposite directions every hundredth of a second? A particularly tricky phenomenon to find an analogy for, at least from the realms of water works.

Oh yeah, I agree. It took me a while to find an anolgy for it..

..now lets keep in mind that these analogies are meant for beginners. People just starting off and having a hard time understanding electromotive force and all of its beautiful and deadly applications....

I use this type of analogy to explain forward and back flow on alternating current.

The screw. I pick up a screw and say. Lets put an imaginary border long ways down the screw. the top part of the screw is the positive feed. The bottom half of the screw is negative feed. The screw spins in one direction, but every time a portion of the screw spins it has the potential to be negative or positive depending on its phase at the chosen frame. So in this case, the screw isnt really going in any specifice direction, but is merely a potential to move through the path of least resistance. The actual electron particles, like the threads of a screw, hang on the outer edge of the circuit. In fact this rings very true when we consider that "electrical power" is the "bumping" of valence electrons of whatever element used as its conductor. Valence being the outer shell of electrons of the atom. This also leads up to me explaining what Hysteresis is

http://en.wikipedia.org/wiki/Hysteresis

http://en.wikipedia.org/wiki/Skin_effect

Thats when I pull out a copper pipe and and say that the actual copper is where the electrons follow along the wire, and that the outer barier of the wire/circuit is the path of least resistance in and of itself. The electrons tend to avoid the core of its medium. This is why the wires become brittle compared to the load X load time X current draw. Aluminum wires suffer HORRIBLY from hysteresis loss. Most importan circuitry are made with gold or silver wire. Silver being the best conductor known to man (because of its generous valence), but being difficult to work with because of its high (higher than copper) oxidation/tarnish rate.

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Never liked the water analogy anyways. Much better to read up on potential theory and basic E/M.

Agreed. But if you have a dumbass first year apprentice, then you have to give him pictures to help

You know...like a picture book for elementary students..hand him some crayons and hope he gets the concept

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@ Rev ... I've never heard the water analogy before. It's not perfect, but it works nicely for what you're using it for and I may use just use it myself.
Nice one.

Its not perfect. Its a primer to help beginers get into the train of thought...to get the basic concept of it beyond abstract numbers