[Closed] Electricity - it just struck me...

isn't it the movement of electrons? works in a similar way to osmosis, positive has lots of them and they 'flow' to the negative.

or maybe I can't remember what went on in physics either.

Absolutely unfathomable.
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I'd say somethign along the lines of.
Electricity is the flow of electrons through a conductive medium casue by a combination of differing atomic potential energies and or movment of said conductor through a magnetic field.

the movement of electrons

http://www.edu.pe.ca/kish/Grassroots/Elect/whatis.htm

It's a kind of magic, but like water. Do Not Touch.

If you really want to break your head,

Electricity 'flows' from positive to negative, however the actual physical movement of electrons goes from negative to positive. So a battery in effect sucks rather than pushes.

As long as I can visit stw site then I couldn't give a cheesy wotsit.

Magic.

isn't it the movement of electrons? works in a similar way to osmosis, positive has lots of them and they 'flow' to the negative.

As Cougar pointed out, when they were working out which was positive and which was negative (the idea being that "electricity" flowed from +ve to -ve but they couldn't actually do a test to check), they took a 50:50 punt and got it the wrong way round...

Never mind that. How does gravity work?

@Cougar. I always took the +ve to -ve thing as just circuit current rather than "true current" as it howe the electrons are flowing as circuit current was just a useful anology used to liken the flow electricity to that of water from high potential / pressure to low potantial / pressure. I know there is the the idea of representing the flow of electron holes but I've never really liked that anology.

It's the combination of Pixies and Aliens fighting in NooNoo Dust Clouds just above the Moons atmosphere, the Clangers could see them, you/we can't.

HTH

You will need to brush up on your differnetial geometry to learn about gravity.

The electron was discovered by J. J. Thomson in 1897 but for much more than a century before that moment, people had already been studying electric (and magnetic) phenomena, even quantitatively, and they had already fixed some convention which charged objects or sides of a battery are positive and which of them are negative.

Because this convention was already established, there was absolutely no freedom in the decision about the sign of the electron's charge. It was simply measured in the cathode rays etc. and it turned out to be negative.

Historically, the first man to decide about a sign convention for the electric charge was probably Benjamin Franklin in the 18th century. His model of electricity assumed that charged objects contain some fluid – it's the electric charge of a continuous type (the similarity with phlogiston, the fluid that was believed to personify heat, can't be overlooked). If there's too much of this fluid, which is naturally identified with the plus sign, he would talk about the positive electric charge and vice versa.

Up to the moment when the elementary particles were being discovered, there was no way to prove that one of the two sign conventions was better than others. In fact, even today, it's not true that the opposite sign convention would be "better" in any sense. Electrons could carry a positive charge in the opposite convention but protons and nuclei (and up quarks) that are equally important (and, in the case of up quarks, equally fundamental) would be negatively charged while they're nicely positively charged in the world around us.

Once a convention is fixed for the electric charge, a natural convention emerges for the sign of the current, voltage, and many other electric observables, too. It just happens that in the circuits, the arrows for the current have the opposite direction than the velocities of the electrons but this discrepancy only became visible once people knew that the currents was composed of the negatively charged electrons which was a long time – a century – after Benjamin Franklin's setting of the convention. This apparent discrepancy causes no problems as long as we carefully follow it and realize (and, when necessary, emphasize) that the arrows represent the current according to the established conventions and not the electrons' velocity.

One should also point out that there exist conductors where the conductivity is guaranteed by positively charged carriers (or both), for example in solutions (positively charged ions) or semiconductors (holes). In those conductors, the signs of the current agree with the sign of the velocity of the (positively charged) carriers.

http://physics.stackexchange.com/questions/68471/who-and-why-started-the-electrons-are-negative-protons-are-positive-convent

Movement of electrons... Where are they moving and how?

Google tells me an Electron is "a stable subatomic particle with a charge of negative electricity, found in all atoms and acting as the primary carrier of electricity in solids."

So are they moving from one atom to another? Because that would hurt my brain a bit if they are... Surely stuff in an atom is pretty well contained?

Just summarise it in 14 words or fewer, like a good candidate would. 🙂

as circuit current was just a useful anology

My understanding was that it was picked arbitrarily before they actually knew about electron flow. Whether or not that's an urban myth though, I'm not sure.

Electricity isn't any one thing; its a general term that covers a pretty broad spectrum.

Never mind that. How does gravity work?

Surely stuff in an atom is pretty well contained

Nope...

So are they moving from one atom to another? Because that would hurt my brain a bit if they are... Surely stuff in an atom is pretty well contained?

Protons and neutrons are (that's nuclear physics). The electrons are the swingers of the atomic world, though.

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Cougar - Moderator

Electricity 'flows' from positive to negative, however the actual physical movement of electrons goes from negative to positive. So a battery in effect sucks rather than pushes.

I discovered this in physics class, by answering all the questions in a test wrong and subsequently breaking the teacher's head when she came to mark it, as she couldn't tell if I was really advanced or really stupid.

I understand it as a movement of electrons - and for that to occur you have to have a quantity of 'free electrons'. So conductors like most metals have free electrons, whereas most plastics have no free electrons so are insulators.

Cougar - Moderator

If you really want to break your head,

Electricity 'flows' from positive to negative, however the actual physical movement of electrons goes from negative to positive. So a battery in effect sucks rather than pushes.

I'm probably wrong, but I thought this was just a convention thing....that in the early days of electricity, people assumed that the flow was from positive to negative and this has just stuck. But the actual flow of electrons is from negative to positive (as they are negatively charged, so slow towards the positive end of a circuit).

There's quite a good description of what I mean on Wikipedia:

Conventions
In metals, which make up the wires and other conductors in most electrical circuits, the positively charged atomic nuclei are held in a fixed position, and the electrons are free to move, carrying their charge from one place to another. In other materials, notably the semiconductors, the charge carriers can be positive or negative, depending on the dopant used. Positive and negative charge carriers may even be present at the same time, as happens in an electrochemical cell.

A flow of positive charges gives the same electric current, and has the same effect in a circuit, as an equal flow of negative charges in the opposite direction. Since current can be the flow of either positive or negative charges, or both, a convention is needed for the direction of current that is independent of the type of charge carriers. The direction of conventional current is arbitrarily defined as the same direction as positive charges flow.

The consequence of this convention is that electrons, the charge carriers in metal wires and most other parts of electric circuits, flow in the opposite direction of conventional current flow in an electrical circuit.

So. When electricity is flowing through a liquid, is it still electrons flowwing from one end to another or is it the ions? Or a bit of both? I seem to remember a chemist teacher telling me that all the ions will eventually end up at one end, which confused me!

Electricity - it just struck me...

Like lightning?

On the silly -ve and +ve electron flow, I've always thought of it like this:

The battery is losing the electrons through the -ve end, so therefore getting less so that's why [u]negative?[/u]

Oh hang on, electrons have a -ve charge, so if you're losing a negative that makes you positive, so that doesn't make sense anymore... damn it.

Just don't start asking yourself how some solids are transparent and other very similar ones aren't. Or why where's no transparent metals 😉

Having to explain this stuff to a curious 5-year-old is fun...

So [url= http://digitalcommons.unl.edu/cgi/viewcontent.cgi?article=1163&context=physicskatz ]this[/url] article seems to suggest that it's the ions drifting to their respective electrodes (cations to the -ve, anions to the +ive ends) and that the electrons do not move, as they would in a solid metal for example. So there must come a time when all the cations are at one end and the anions at the other, right? And therefore the liquid will no longer conduct electricity?

If you really want to break your head,

Electricity 'flows' from positive to negative, however the actual physical movement of electrons goes from negative to positive.

Someone tried to explain to me once that the electron flow model is also a simplification and, possibly depending on the source of the electricity, you also get electron [i]hole[/i] flow or something...

...my brain pretty much shut down at that point.

Think of scooby-doo backgrounds and you'll see why the current vs electron movement works 😉

"Electricity" is a term used to describe several phenomena associated with the presence & movement of electric charge - you really need to specify if you are referring to charge, field, potential or current when discussing electrickery in any detail

I would explain it as a series of properties defined by the physics of some particles to have forces that will interact with other particles that will under certain circumstances produce currents, fields and magnetism.

probably wildly wrong though

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you also get electron hole flow or something...

Line up a row of pennies.

Move the rightmost one right a bit. Move the next one to the place the other one just was. Repeat down the line.

The pennies are all moving to the right. But the [i]gap[/i] moves left.

@verses. Electrons exist in differnet spaces / orbits / energy levels around a atom, depending on the struture of the atom there are diffrent probablities of where thoese electrons may be in diffrent shaped clouds. If two atoms can gain a lower energy level by sharing or allowing an electon to move between each of their orbits there by changing the shape of these electns outermost orbits so the probility of finding that electron in either of these two orbits. This forms a bound between the two attom. Simarly if one atom if more potivly charged than the other the same altering of the probabilty space of where the electon lies is alter making a differenet type of bond. So electons are free to move between attoms. This is not electcity but shows how electons can be shared.

electron hole flow makes more sense when talking about semiconductors. even then it's not really flow along a wire in the conventional sense but distribution of holes and electrons as a result of the doping of the semiconductors and the charges and potentials applied.

Someone tried to explain to me once that the electron flow model is also a simplification and, possibly depending on the source of the electricity, you also get electron hole flow or something...

...my brain pretty much shut down at that point.

Imagine one of those automatic sweet making machines, which have a conveyor belt with lots of little moulds on it, hot sugary stuff goes into the moulds at one end, travels along cooling down, and cool sweets drop out at the other. Then the conveyor wraps underneath and the empty holes flow back to the beginning.

Holes flow one way, electrons/sweets flow the other.

😀

Someone tried to explain to me once that the electron flow model is also a simplification and, possibly depending on the source of the electricity, you also get electron hole flow or something...

Most semi conductors work in this way. I think?

Just don't ask me to explain quantum tunneling

Incidentally I had the same realisation as the OP and decided it was about time I learnt the secrets of electrickery and taught myself some electronics.

There are lots and lots of good YouTube videos about the very basics, but even something as apparently simple as a capacitor appears to work by witchcraft and soon you learn there are all kinds of other mystical properties and considerations you didn't know about (e.g. impedance, inductive reactance and capacitive reactance).

I can now plug a few chips and components together on a breadboard but I am still constantly surprised and befuddled with what comes out 😀

Just don't ask me to explain quantum tunneling

Can be summed up as "Electrons don't know where they are" 😉

but they can know within a probaility of where they should be...

At least I think that it is it. Probably.

capacitors are only witchcraft if you think in the DC domain.

but they can be well fun for making things go bang! 😈

Well let me see, in simple terms without Googling anything.

It is the activity of electrons in conductors, and a bit like how objects always want to lose potential energy (fall), electricity has potential (which we put in via power stations etc) but always wants to go to earth (zero potential) and we can harness the resulting work to power things.

In a broader sense it's inextricably linked with magnetism, light (light itself not light bulbs), and governs the fundamental properties and behaviour of matter.

Electrickery. Telling Bone. 'Tis all a mystery.

True story,

My OH asked if we could take a battery off a bike and take it upstairs to charge. I replied, "potentially."

Then I spent the next ten minutes giggling quietly to myself whilst she looked at me shaking her head.

Rockplough - Member

In a broader sense it's inextricably linked with magnetism

****ing magnets? How do they work?

Found the explanation that messed with my head:

"Conventional current is wrong" ...is actually wrong.

It's wrong because it's based on the widespread misconception "all electric currents are electron flows."

Why would science+engineering use conventional current? Because protons flow, of course. For example in battery acid, in proton conductors in fuel cells, and in electroplating tanks. Also, currents made of positive ions can flow in oceans, dirt, human bodies, alkaline battery electrolyte, and plasmas during sparks, neon signs, fluroescent tubes. Positive ions are atoms with more protons than electrons, while negative ions have more electrons than protons (and positive hydrogen ions? They're called "protons." Duh.) Positive ion currents are usually accompanied by negative ions flowing backwards at the same time in the same conductor (so, which way is the "true" current in an electrolyte, if it's actually made of two opposite populations of charge flowing in two opposite directions?)

In all of the above, we simplify things by pretending that negative charge, if flowing backwards, is the same thing as positive charge flowing forwards. Then we add the pos-charge and neg-charge currents together. Our clamp-on ammeters, they directly measure conventional current. An ampere flowing in the ground or in a human arm may be composed of equal and opposite ion flows (with no electron flows,) but your DVM amps-setting will report it as one ampere of conventional current.

Where did the misconception arise? Easy: electric currents in metals are electron flows, same as in vacuum tubes. Some grade-school and tech-school authors decided to teach that, since currents in metal wires are electrons, that means that all currents everywhere are electrons. Just ignore the currents in glowing gas, liquids, human bodies, earth, and battery electrolyte. Screw up the minds of the poor chemistry students even before they take their first chem class.

When we get right down to it, saying "conventional current is wrong" ...that's STUPID, it's a confusing misconception being spread by grade-school teachers, just like when they teach that "it's not the volts that kills you, it's the amps." It does a great disservice to anyone who goes into science and engineering, where their professors have to spend time trying to remove the misconceptions that "all currents are really just electrons," and "conventional current is wrong because positive charges cannot flow."

Electron-flow applies to solid metals, not solids. But conventional current isn't "wrong" in the first place, since conventional current isn't a flow of positive particles. Instead it's a coverup; a simplification. Ammeters measure conventional current, they ignore the actual particle flows. Ammeters don't care whether the current is positive sodium ions flowing one way, or negative chloride ions flowing backwards, so ammeters aren't "wrong." Instead they report a simplified concept, and they conceal the true direction/speed/makeup of the particle flows. If someone prefers reality, then they must abandon ammeters entirely, and instead use some sort of instrument which senses the separate particle populations and their separate drift velocities.

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All taken from the comments on this video, which I thought was a nice concise explanation till I read the comments!

Electricity is a force that is passed down copper cables by a process similar to squeezing an orange down the sleeve of a jumper.

The contractions are so small as to be imperceptible to the human eye (or hand since you can't feel them if you hold an insulated live cable).

If you hold an uninsulated live cable the cable will think you're a predator and will attempt to throw you off and will make a cracking noise to scare you.

Cables have to be firmly clamped at the ends (inside a 13a plug for example) in order to give the "swallow" effect something to brace against. THis is why it doesn't work as well if the connection is loose.

HYH

I am not an electrician

Electron-flow applies to solid metals, not solids. But conventional current isn't "wrong" in the first place, since conventional current isn't a flow of positive particles. Instead it's a coverup; a simplification. Ammeters measure conventional current, they ignore the actual particle flows. Ammeters don't care whether the current is positive sodium ions flowing one way, or negative chloride ions flowing backwards, so ammeters aren't "wrong." Instead they report a simplified concept, and they conceal the true direction/speed/makeup of the particle flows. If someone prefers reality, then they must abandon ammeters entirely, and instead use some sort of instrument which senses the separate particle populations and their separate drift velocities.

Did anyone else end up reading this in Jon Pertwee's voice by the time they were halfway through it, or is it just me?

Can we do the double slit experiment now? For total WTF it's hard to beat:

I just use the water metaphor, it's mostly pretty effective. Except for that time I accidentally connected 2 12V lives on my PC together and it went on fire- you don't get that with plumbing.

Next, a quick guide to Quarks, Strangeness, Charm and colour...
Lolz at Cougar's battery-charging joke!

No no. Not the double slit. That's just.... aaaaaagh.

It's sparky stingy stuff that you can't play with in the bath.

Sometimes the sky makes it to keep us humble.

Though it's been around for ages, we haven't been aware of it for long... what will we find next?

It always seems to mess with peoples heads that in a copper wire an electron only travels at a few centimeters per hour, but the electricity is there as soon as you turn the switch on... so how do the electrons further up the wire know to start moving? ;o)

I teach electricity is like a mexican wave (get ready class for a huge mexican wave of shoves with the end child falling off their stool into the lamp) or the wire a tube full of glass marbles as electrons, the electron getting to the light is not the one leaving the battery. hence the very high speed.

I also mention transparency is about a substance having no crystals or cell like structure to bounce the light around.

Of course, this never comes up in exams - but everyone should know why the sky is blue, particularly if you teach in Rayleigh.

Have you thought about teaching it like this? 🙂

A DIY step up and down transformer showing how the national grid works has caught out many a teacher. CLEAPSS is useful on this. Electricity is a very hard thing to teach, Flemming left hand rule? How on Earth does motion of a conductor with "free electrons" in a magnetic field induce a flow of electrons? When a particle acts like a wave and then changes back to a particle behaviour when you look at it, that's odd and beyond me.

No idea what it is except it make the house a bit lighter than using candles (4)

AND.. I leaned my bike against a fence last Saturday & when I tried to undo the skewer on the front wheel.......
I'll let you guess the next bit.

It tastes hurty

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I love how all the explanations are DC so far.

AC electricity is really going to blow your mind - the current flows both ways but the power only flows one...

PS you're all trying too hard with visualising electrons and holes etc. they're very small really and most of the time they move about randomly only generally drifting in the direction indicated by the current (conventional or otherwise).

Have you thought about teaching it like this?

That's brilliant. It's like he knows the theory but not the commonsense stuff.

Edit - had a look at his channel and it's obviously a spoof. Still funny though.

AC electricity is really going to blow your mind - the current flows both ways but the power only flows one...

And if AC blows your mind, whatever you do don't think too hard about three-phase 😀

I looked at that 3 phase current stuff - as far as I can see it doesn't add up to anything much.

And if AC blows your mind, whatever you do don't think too hard about three-phase

I like to think I'm a geeky kind of guy, and three-phase properly baffles me.

3^0.5

I think of it like this:

- DC is like pushing a car along the road

- AC is like a single cylinder piston engine

- 3-phase is like a ****el rotary engine

That's probably a really bad analogy.

I read an interesting artical about some good theoretical and pratical experments to consider a 6 phase system for electrical pwoer distribution, it had some good advantages but the extra infistructure costs made it too expensive. Now with cheap highpowerd power mosfets and IGBTs we could loaclaly create 6 phase systems within sitautions where it would be advantagouse if the units to used it where made.

Are you sure 6 phase wasn't just centre tapped 3 phase?

Just don't start asking yourself how some solids are transparent and other very similar ones aren't. Or why where's no transparent metals

Having to explain this stuff to a curious 5-year-old is fun...

Remember, you are just talking about transparency in the optical part of the spectrum. There is a whole load more head hurting stuff to think about when you go wider.