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What is Electricity?
- SunSparc 11y agoGreat little intro to electricity. SparkFun has some good educational tutorials.
- erehweb 11y agoThere 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."
- SunSparc 11y agoHaha, I daresay that student did poorly on the exam.
- murbard2 11y agoI would understand the material better if it were presented as an armadillo analogy. http://smbc-comics.com/index.php?id=3892 http://smbc-comics.com/index.php?id=3892
- tim333 11y agoFeynman explaining electricity as mentioned https://www.youtube.com/watch?v=kS25vitrZ6g&feature=youtu.be&t=8m17s https://www.youtube.com/watch?v=kS25vitrZ6g&feature=youtu.be... Tragically lacking in armadillos though. Maybe he could have got further if he'd included a few.
- dspillett 11y agoElectricity 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.
- andars 11y agoEverything goes downhill once you see the magic smoke come out of an IC.
- 0xdeadbeefbabe 11y agoElectricity is being in love. Feynman possibly agrees? http://www.lettersofnote.com/2010/06/you-dont-understand-ordinary-people.html http://www.lettersofnote.com/2010/06/you-dont-understand-ord....
- johncolanduoni 11y agoWow, one of my favorite scientists dissing one of my least favorite. Thanks for the link!
- tim333 11y agoThat's quite funny. I see from Wikipedia Feynman was on Wolfram's PhD thesis committee. He can't have been too impressed with Wolframs people skills.
- snaky 11y agoThat skills are legendary https://www.reddit.com/r/programming/comments/8l3bq/wolfram_and_lisp/ https://www.reddit.com/r/programming/comments/8l3bq/wolfram_...
- mrow84 11y agoIs 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? https://cdn.sparkfun.com/assets/9/5/6/1/4/519fcd42ce395f804c000000.gif https://cdn.sparkfun.com/assets/9/5/6/1/4/519fcd42ce395f804c...
- johncolanduoni 11y agoYep! These are called plasmons[1]. They are sort of like sound waves for electrons, in that they are compression (i.e. longitudinal) waves. [1]: https://en.wikipedia.org/wiki/Plasmon https://en.wikipedia.org/wiki/Plasmon
- mrow84 11y agoSweet, 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?)
- heatish 11y agoI'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"
- digi_owl 11y agoI 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.
- lr4444lr 11y agoIt'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?
- delinka 11y agoSomething 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.
- togusa 11y agoMy EE professor said to me once: "Quantum electrodynamics and shit. I'm not a physicist." I wasn't all that impressed with that answer until many years later after reading Feynman lectures.
- LgWoodenBadger 11y agois electricity any different than ionized hydrogen?
- delinka 11y agoAbsolutely. 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")
- LgWoodenBadger 11y agoOk, but hydrogen's nucleus is only a proton...
- shostack 11y agoBit 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". Absolutely fascinating world we live in. [1] http://qntm.org/ra http://qntm.org/ra
- SunSparc 11y agoSo 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".
- ajross 11y agoYeah, 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.
- SunSparc 11y agoGood clarification.
- sebkomianos 11y agoMaybe 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).
- emcrazyone 11y agoCouldn'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 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.
- SunSparc 11y agoI just sent your feedback to Sparkfun: https://twitter.com/SunSparc/status/655108454042832896 https://twitter.com/SunSparc/status/655108454042832896 We will see if they update it.
- nerd_stuff 11y agoTo 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.
- emcrazyone 11y agoLol, 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.
- pg_is_a_butt 11y agowhat are magnets and how do they work?
- jimmahoney 11y agoI like Dave Barry's explanation of electricity (e.g. http://www.comp.leeds.ac.uk/Perl/Misc/electricity.txt 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 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."
- agumonkey 11y agoFunny 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 ```
- SunSparc 11y agoGreat read! Thanks for that.
- noonespecial 11y agoIts 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".
- powertower 11y ago> 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?
- aaronkrolik 11y agoElectric 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.