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What is Electricity?

learn.sparkfun.com

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Re: What is Electricity?

#31

Post by SunSparc »

emcrazyone wrote: post #25

Couldn't read much past the statement: "Electricity is briefly defined as the flow of electric charge, but there’s so much behind that simple statement" Electricity is the force not the flow. The flow is the current. The term, "Electricity" in every college course I had on it in getting my degrees is always the EMF (Electromotive Force). Sorry to nit pick but I just have a real problem when articles are written from…

I just sent your feedback to Sparkfun: https://twitter.com/SunSparc/status/655108454042832896

We will see if they update it.

Re: What is Electricity?

#32

Post by ajross »

SunSparc wrote: post #29
shostack wrote: post #24

Bit of a tangent, but reading this was really interesting in the context of the book I'm reading now, "Ra."[1] It takes place in a modern day world where "magic" was discovered decades ago and is now a formal science with graduate programs right up there with engineering and physics. It has rules, and in fact one character just created a magical quine (which was apparently thought to be impossible). If every sufficie…

So true. If the Egyptians could see what we play with every day, they would be amazed. I imagine there is quite a bit of shock for people in deep jungle/desert tribes that still live in huts when they are introduced to "modern" technology. Magic is probably the best way for them to explain it initially. Of course, "magic", usually just means, "something I do not understand".

Yeah, but that's driven by familiarity not understanding. A median western marketing executive has no better understanding of electrodynamics than your amazonian tribeswoman, yet isn't surprised by the radio in his phone.

Re: What is Electricity?

#33

Post by SunSparc »

ajross wrote: post #32
SunSparc wrote: post #29

Earlier quoted context omitted.

So true. If the Egyptians could see what we play with every day, they would be amazed. I imagine there is quite a bit of shock for people in deep jungle/desert tribes that still live in huts when they are introduced to "modern" technology. Magic is probably the best way for them to explain it initially. Of course, "magic", usually just means, "something I do not understand".

Yeah, but that's driven by familiarity not understanding. A median western marketing executive has no better understanding of electrodynamics than your amazonian tribeswoman, yet isn't surprised by the radio in his phone.

Good clarification.

Re: What is Electricity?

#34

Post by nerd_stuff »

emcrazyone wrote: post #25

Couldn't read much past the statement: "Electricity is briefly defined as the flow of electric charge, but there’s so much behind that simple statement" Electricity is the force not the flow. The flow is the current. The term, "Electricity" in every college course I had on it in getting my degrees is always the EMF (Electromotive Force). Sorry to nit pick but I just have a real problem when articles are written from…

To say electricity is roughly the flow of charge looks perfectly fine to me. Opening statement of the wikipedia article on electricity:

> Electricity is the set of physical phenomena associated with the presence and flow of electric charge.

I doubt the article will steer people wrong. The gravity/e-field analogy is accurate, and they're clear to state that Bohr model of the atom is a useful model while providing a link to more info so interested readers could dig in there if they wanted.

> Electricity is the force not the flow...."Electricity"...is always the EMF

Speaking of details the Electromotive Force isn't a force because it doesn't have Newtons for units. EMF times charge does give a force but EMF alone is just Volts. In circuits we may think of it as if it's a force, and it has force in the name, but it's just a potential difference.

Re: What is Electricity?

#35

Post by etep »

emcrazyone wrote: post #25

Couldn't read much past the statement: "Electricity is briefly defined as the flow of electric charge, but there’s so much behind that simple statement" Electricity is the force not the flow. The flow is the current. The term, "Electricity" in every college course I had on it in getting my degrees is always the EMF (Electromotive Force). Sorry to nit pick but I just have a real problem when articles are written from…

I disagree with the nitpick. Electricity is not a technical term. In its common usage, it encompasses many effects and broadly invokes many technical concepts, i.e. among them EMF or voltage, current, electromagnetic waves, etc. etc.

This article is not written for physicists, engineers, or anyone else so technically trained. If it were, it would read as follows: "Electricity is a vague term used to variously refer to the many aspects of electromagnetic phenomena."

If you want to keep that sentence, and cover your bases, you could reword as "the flow of electric charge, the potential to cause the same." And in any case, the escape clause already exists as "there’s so much behind that simple statement."

Re: What is Electricity?

#36

Post by powertower »

> A negative charge has an inward electric field because it attracts positive charges. The positive charge has an outward electric field, pushing away like charges.

If this was true, then why does a negative charge not attract other negative charges?

Re: What is Electricity?

#37

Post by noonespecial »

jimmahoney wrote: post #27

I like Dave Barry's explanation of electricity (e.g. http://www.comp.leeds.ac.uk/Perl/Misc/electricity.txt ) including "the electric company sends electricity through a wire to a customer, then immediately gets the electricity back through another wire, then (this is the brilliant part) sends it right back to the customer again. This means that an electric company can sell a customer the same batch of electricity tho…

Its actually worse than that. You keep the same electrons, the electric company just wiggles them back and forth and then bills you for it.

As my prof used to say about AC, "you don't pay for the swing, you pay for the push".

Re: What is Electricity?

#38

Post by aaronkrolik »

powertower wrote: post #36

> A negative charge has an inward electric field because it attracts positive charges. The positive charge has an outward electric field, pushing away like charges. If this was true, then why does a negative charge not attract other negative charges?

Electric field forces are drawn as if you were placing a small positive charge in the field. The wording is awkward. If convention used a small negative test charge, the language (and diagram arrows) would be flipped. "inward electric field" is only with respect to a positive charge, not to all charges.

Re: What is Electricity?

#39

Post by nerd_stuff »

shostack wrote: post #24

Bit of a tangent, but reading this was really interesting in the context of the book I'm reading now, "Ra."[1] It takes place in a modern day world where "magic" was discovered decades ago and is now a formal science with graduate programs right up there with engineering and physics. It has rules, and in fact one character just created a magical quine (which was apparently thought to be impossible). If every sufficie…

> I wonder what the turning point was when people stopped thinking of electricity as magic and instead thought of it as science

Once they could make predictions and those predictions were verified by reality. "When I flip this switch the light will turn on.....When I move this magnet past this wire I can shock my lab assistant...."

I don't know much about D&D but I would venture the guess that electrons are far stranger than mana. I mean, not only do they have a wavelength[0], you can do the Double Slit experiment with them[1], but they also have an intrinsic angular momentum and there are rules of which electron can be where based on this "spin"[2]. That's just for starters.

Calling them "mana" (whatever that is) might not be any more wrong than calling them particles.

0 - https://en.wikipedia.org/wiki/Matter_wave 1 - https://en.wikipedia.org/wiki/Double-slit_experiment 2 - https://en.wikipedia.org/wiki/Spin_%28physics%29

Re: What is Electricity?

#40

Post by andars »

dspillett wrote: post #6

Electricity is a myth. Everything is really run by blue smoke and your cables are tubes to move it around. The wire inside the cable is just for strength. You can see this is true when something shorts. The resulting hole in the system allows some blue smoke to escape, and the machine then stops working.

Everything goes downhill once you see the magic smoke come out of an IC.
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