[Needaask]

Hi I have a few questions on electricity and chemistry, thanks for the help

1) How does electron flow?
When I have a simple circuit say a battery connected with a wire from the positive end to the negative end, the way i think electrons flow is like this:
1 electron from negative end of battery comes out and displaces the electron in the wire. While that happens the electron in the metal also displaces the next electron in the metal and this process goes all the way to the postive end. At the positive end an electron from the metal is being displaced into the battery.

So if this were the case, the 'net' displacement for the electron to move from the negative the the positive end is just the time taken for the electron to move out and displace the other electrons from the wire. In other words the flow is instantaneous. Meaning if i set 1 'net' electron to flow from that light bulb case, and i compare 2 different types of wires with different conductivities, the wire that has more resistance would be harder to displace so it would take longer to displace an electron from it. But still the instant the electron from the negative end completely displaces that electron in the metal, so would the electron in the metal completely displace the electron in the positive end of the battery.

However, when i watch lightning strike like this http://www.gifbin.com/982185 it appears that the electron takes a while to reach the other end. Also I'm not too sure if I'm having the right thought process.. I learned that V=RI and when learning that it shows that the higher resistance only reduces the number of electrons per second and it does not slow the electrons. So I'm quite confused by all this. I guess perhaps if i switched it to a higher resistance wire the only change would be the number of electrons and not the speed of displacement?

The image I was thinking of is like this http://www.askaboutireland.ie/learning-zone/primary-students/3rd-+-4th-class/science/electricity/what-is-electricity/ it shows that as one electron comes out from the battery, another comes back inside so I'm not sure about why in the lightning strike the electrons would appear to move from one end to another. My idea is like this: http://postimg.org/image/3ljzyp61h/full/ so as an electron gets pushed to A an electron is also pushed to B at the same time.

So within this 1 question I found that I don't really understand how electrons flow in conductors.

2)
When doing electrolysis we have an anode and a cathode in the solution. And in the solution if I had either pure water or dilute NaCl(aq) solution, the salt solution would be a better conductor. However, since the H+ ions and the OH- ions would preferencially get oxidized/reduced how does having those addition Na+ and Cl- help with the discharge of H+ and OH- ions?

3)
When i have a lightning, it is because the cloud is negatively charged while the ground is positively charged. So the air is ionized to form plazma (positive ions and negative electrons). Then from here, how does the current flow? Does it displace the negative electrons? But then again the negative electrons would go to the ground right? So I'm a bit confused here.

4)
Again when a lightning strikes water, how does having more ions present make it more conductive? Because I don't really see lightning striking water as a simple electrolysis like in question 2. Or is the part where electrons reach the water the negative electrode and the earth the positive electrode? So its like the same type of reaction going on where H+ and OH- react with the electrodes?

But then in that case, i don't see how being in the water while that happens would kill you. Since now even if there is a current, it's only free mobile ions moving about which is the same thing as putting my hand in a solution of NaCl(aq).

Thanks so much for the help

[Arkcon]

That's quite a lot to read, and to address point by point.  However, you have made one critical mistake at the start, that has caused you to to become confused.  A lightning strike, is not the same as current flow in a conductor.  Start with this description from Wikipedia:  http://en.wikipedia.org/wiki/Lightning#Downward_leader_formation_for_negative_CG_lightning and you'll see that a lightning strike is a charged channel that forms as ions build gradually, and then the electrons charge the air in the channel, causing the air to glow.  That's the only reason you can see a lightning bolt reach from sky to ground.  Electrons travel at nearly, but not exactly, the speed of light.  You'd never see them travel, if lighting were just a stream of glowing electrons.

[Needaask]

That's quite a lot to read, and to address point by point.  However, you have made one critical mistake at the start, that has caused you to to become confused.  A lightning strike, is not the same as current flow in a conductor.  Start with this description from Wikipedia:  http://en.wikipedia.org/wiki/Lightning#Downward_leader_formation_for_negative_CG_lightning and you'll see that a lightning strike is a charged channel that forms as ions build gradually, and then the electrons charge the air in the channel, causing the air to glow.  That's the only reason you can see a lightning bolt reach from sky to ground.  Electrons travel at nearly, but not exactly, the speed of light.  You'd never see them travel, if lighting were just a stream of glowing electrons.

Hi thanks for the repl

I shouldn't have assumed that a lightning was a simple flow of electrons. Could you explain the mechanics of the lightning strike?

It appears that the air is being ionized to form positive ions and negative electrons. But I'm not sure what lightning itself is..

Other than this is my idea in a normal circuit correct when as electrons from the negative end gets displaced out, simultaneously electrons would be displaced into the positive end?

Thanks again for the help

[Corribus]

1) How does electron flow?

From high potential energy to lower potential energy, of course!

Do you mean in a metal (conductor)?  You need to look into band theory.  Electrons (and holes - can't forget those!) flow through empty orbitals, and in a metal there are accessible empty molecular orbitals at all temperatures.  The "force" which causes unidirectional flow is an electrical potential from a battery.  Resistance is caused by thermal motions of nuclei and imperfections in the lattice, which interfere with the flow of electrons.

[Needaask]

Hi

My teacher told me something about that before. He told me that for metals it is easy for the electrons to get displaced as it does not take energy to displace it. That's where I thought of how the current is like. I'm thinking that the super slowed down current would look like this: Electron comes out of negative end causing the next electron in the conductor to move away and so on - all the way to the other end of it. Something like the opposite of a domino blocks game where the next block falls when the previous touches it, its more like when i push one over the rest gets pushed over too. So there's no time gap between the first block falling and the last block.

But I'm having trouble associating this with lightning strike though..

Thanks so much for the help

[Corribus]

Electrons don't displace each other as much as they hop from vacancy to vacancy.  You can't really understand current with electrons only.  Holes are also treated as quasiparticles (positively charged) which move in the opposite direction simultaneously.  What distinguishes a conducting material from a semiconductor or insulator is the number of available gaps at a given temperature.  As an analogy, think about trying to cross a pond by stepping stones.  The more stones there are and the closer they are together, the faster you can cross.  Even in a metal there is resistance, though, and this resistance would be akin to the stones moving around, as platforms in a videogame.  The faster the stones move, and the longer distance you have to travel, the slower your progress.  In a semiconductor, the stones only appear if the temperature is hot enough.

A lightning strike is different because air is an insulator.  Lightning is not so much different from a typical capacitor reaching a fail point - the clouds and the ground are your parallel plates and the air is the dielectric medium. Effectively what happens is the charge builds and builds.  This creates an electric field.  As the field strength builds, the air reaches a point where the field is strong enough to strip electrons from gasses in the air.  Ionized air is a much better conductor than neutral air, which creates a path for electron movement.  It's a dynamic process though, as the previous poster said, and I don't believe every aspect of it is understood.

[Needaask]

Hi so actually how would current flow in a metal? Was my idea of everything moving together at the same rate wrong?

I was reading up on the electron holes and i found this analogy "Hole conduction in a valence band can be explained by the following analogy. Imagine a row of people seated in an auditorium, where there are no spare chairs. Someone in the middle of the row wants to leave, so he jumps over the back of the seat into an empty row, and walks out. The empty row is analogous to the conduction band, and the person walking out is analogous to a free electron.
Now imagine someone else comes along and wants to sit down. The empty row has a poor view; so he does not want to sit there. Instead, a person in the crowded row moves into the empty seat the first person left behind. The empty seat moves one spot closer to the edge and the person waiting to sit down. The next person follows, and the next, et cetera. One could say that the empty seat moves towards the edge of the row. Once the empty seat reaches the edge, the new person can sit down.
In the process everyone in the row has moved along. If those people were negatively charged (like electrons), this movement would constitute conduction. If the seats themselves were positively charged, then only the vacant seat would be positive. This is a very simple model of how hole conduction works."

So isn't it like as one person moves out of his seat, another would also start to get up and so on? I'm just not sure if they all happen together (like if i had the 1 vacant seat in the middle and all of them would get up together to move 1 seat to the left so everyone stands up together and seats down together.) Something like this: http://postimg.org/image/6jd2dg2md/full/ so they all move by a bit at the same rate.

As for lightning when the air is ionized, what happens then? The ionized air contains both negative electrons and positive ions. So will the negative electrons all go down to earth (positive) and the positive ions go up to the clouds (negative)? But I was thinking if it would bear any similarity to the electron/hole conduction where electrons move in the metal. But now the positive ions and electrons would be flowing through air.

[Corribus]

So isn't it like as one person moves out of his seat, another would also start to get up and so on? I'm just not sure if they all happen together (like if i had the 1 vacant seat in the middle and all of them would get up together to move 1 seat to the left so everyone stands up together and seats down together.) Something like this: http://postimg.org/image/6jd2dg2md/full/ so they all move by a bit at the same rate.

It's a decent analogy but like all analogies it isn't perfect.  For one thing, the empty row and the full row aren't spatially separated.  But more important is the fact that electrons behave like waves as much as they do particles, which is harder to link to situations observed in your real life.  Things like interference and wave coupling play a large role in conductance physics that just have no classical analogy.

As for lightning when the air is ionized, what happens then? The ionized air contains both negative electrons and positive ions. So will the negative electrons all go down to earth (positive) and the positive ions go up to the clouds (negative)? But I was thinking if it would bear any similarity to the electron/hole conduction where electrons move in the metal. But now the positive ions and electrons would be flowing through air.

Well yes, in a way.  When air molecules are plasma-ized, they become a conductive medium much like a metal which allows a massive and rapid discharge.  I think if you want to know how lightning works, you might read about parallel plate capacitors and dielectric breakdown.  You should be able to find a simple explanation in most intro physics texts.  It's not exactly the same situation but close enough I think for what you want to understand.