There is a story (perhaps apocryphal) that a student at Cambridge [?] was asked this at an exam many years ago.
He said "I'm sorry, I did use to know, but I've forgotten".
"How very unfortunate," said the professor. "In all of history, only two people have known what electricity is. One the creator, and the other yourself. And now one of the two has forgotten."
"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 thousands of times a day and
never get caught, since very few customers take the
time to examine their electricity closely.
In fact, the last year any new electricity was
generated was 1937."
and
"AMAZING ELECTRONIC FACT: If you scuffed your feet
long enough without touching anything, you would build
up so many electrons that your finger would explode!
But this is nothing to worry about unless you have carpeting."
Funny Lagrangian view on natural elements property. Even the other businesses are just selling combinatorics.
ps: really nice kind of humor running in this article, love it
```
you picked up batches of "electrons", which are very small
objects that carpet manufacturers weave into carpet so that they will
attract dirt
you picked up batches of "electrons", which are very small
objects that carpet manufacturers weave into carpet so that they will
attract dirt
```
Is it possible for signals to propagate as waves, without the electrons moving between atoms? Kind of like in this gif, but without them hopping along?
Sweet, thanks. I see in the "possible applications" section of that wikipedia article it is stated that:
"Plasmons are being considered as a means of transmitting information on computer chips, since plasmons can support much higher frequencies (into the 100 THz range, while conventional wires become very lossy in the tens of GHz). However, for plasmon-based electronics to be useful, a plasmon-based amplifier analogous to the transistor, called a plasmonstor, first needs to be created."
So yeah, to all those applied physicists in the audience, hurry up and unleash the plasmonstor! (does anyone really call it that?)
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 sufficiently advanced technology is indistinguishable from magic, I wonder what the turning point was when people stopped thinking of electricity as magic and instead thought of it as science.
When you get into talk about electrons, how they flow, how they transfer between atoms, and how we end up harnessing them, it is very easy for the D&D nerd in me to mentally replace "electrons" with "mana".
> 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.
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.
Maybe it's also worth clarifying that familiarity doesn't mean or lead to understanding. Sometimes quite the opposite (hint hint: newer generation using smartphones, social networks, etc without understanding them at all and then some from older generations remarking how they can be dangerous and upsetting).
I've always wondered about the design choice for the shape of batteries. It seems like the shape would indicate the current is flowing the opposite way than it does. Something about the positive terminal just says to me "I'm shooting electrons this way"
I got the impression from somewhere that plus and minus was defined long before they could track actual electrons, and thus discover that they had them backwards.
Yes, Benjamin Franklin was the first to assign positive and negative, and got the sign wrong. It looks like it took around another century to figure out that detail.
It's an historical accident. But electricity as the flow of positive charge is a pretty reliable model outside of materials science and nano-electronics, so why worry?
Something that bugged me as a kid trying to learn electronics: everything is connected to ground, negative is on ground, so we're dumping electrons onto every path in the circuit. It's the job of the resistor, capacitor, transistor, IC, etc, to direct those electrons, putting their energy to use, and then dumping them back to positive.
Absolutely. To be called "hydrogen" (or any element really), a nucleus must be involved. Electron-free nuclei maintain their elemental identities, they're just positively charged and willing to take on electrons. "Electricity" involves moving electrons, which doesn't always require a nucleus (hence "free electrons")
> 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.
"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 sense of authority (An electronics company) and don't get the details correct. It can kick off a cycle of incorrect learning and confusion if you're relatively new and getting into electronics.
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."
What proof do you have the article wasn't written for physicists, engineers or anyone else so technically trained?
This is the basis for not agreeing? If it is, then it seems you drew an assumption then formed an opinon that is contrary to many college level courses, texts, and teachings I've sat through where electricity is carefully described as the force alone.
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.
Lol, so if it's on Wikipedia it must be true and accurate. Nice. Hey, if it's on the Internet then it must be true.
I think it is reckless. A lot of young up and coming engineers perhaps use sparkfun for their high school electronics work might read this and come away with incorrect understanding of things making new material confusing or longer to understand.
You think what's reckless? The guy who wrote the article has a degree in Electrical Engineering and the article's great.
EMF is not a force and it's not the only thing the word electricity refers to. I've just checked a physics and an electrical engineering textbook and neither refer to electricity or EMF the way you are. I honestly don't know where you're getting these ideas.
In physics there is a fundamental force sosmetimes called The Electromagnetic Force, and in a sense it does describe all of electricity, but it's not the same thing as The Electromotive Force.
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.