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/sci/ - Science & Math

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5540829 No.5540829 [Reply] [Original]

Electricity is hard to understand
Does the electrons push each other like newtons cradle or is it a "pressure"?
How does a conductor hold a charge?
How does static electricity even work

>> No.5540834

it's a force
conductors have a sea of free electrons
static electricity has various mechanisms depending

>> No.5540835

>>5540834
>sea of free electrons
like beta radiation?

>> No.5540841

>>5540835
magnets, how do they work?

>> No.5540893

pls rspnd

>> No.5540899

>>5540893
why not just read the wikipdia article?

>> No.5540927

>>5540841
You can't explain that

>> No.5540940

I may be remembering my GCSE Physics a bit sketchily but I'll give this one a go

Conventional current is said to flow from positive to negative terminals. The actual direction of electron flow, however, is the opposite. How can this work? Let me show you.

Imagine we have a circuit made up of a battery with both terminals connected by a wire of atoms stacked in a row.

Electrons build up on the negative terminal (anode) of the battery. With any anode there must be a corresponding cathode which will be positively charged and therefore can be considered to have a deficit of electrons. As we all know, electrons are negative and are therefore attracted to the positively charged cathode. An electron moves from atom #1, the atom nearest the cathode, to join with this positive charge. Atom #1 now has a positive charge. This has a similar effect on the next atom in line, atom #2, causing an electron to jump to atom #1. Now, atom #2 is positively charged, so an electron from atom #3 moves to atom #2.

Let us say that atom #3 is connected to the anode. The anode has a surplus of electrons and is only too happy to donate one to the positively charged atom #3. The anode is now less negatively charged than it was before so acquires the first electron that jumped from atom #1 to the cathode, thus completing the story.

So let us look at what has happened. Electrons have, in turn, jumped from one atom to the next in the direction from anode to cathode. This is the flow of electrons that fits the definition of a current. But what has also happened is that a "unit of positive charge" has moved from the cathode to the anode. It was only because of the positive charge on the atoms that the electrons moved at all, therefore we can equally say that a positive charge has moved in the opposite direction to the electrons- from cathode to anode. This "positive charge" is what is referred to as "conventional current"

>> No.5541160

>>5540829
>Does the electrons push each other like newtons cradle
No. The main force at work here is good old Coulomb's law; electrons have like charges and repel other electrons.
>or is it a "pressure"?
Electrical potential energy is somewhat analogous to pressure. But it doesn't work by particles bumping into each other, like pressure in a gas. It's just another way of looking at Coulomb's law. Two electrons close to each other have more potential energy than they have far away.

Of course, Coulomb's law is just a special case of Maxwell's equations which give the full laws governing electrical forces. It doesn't account for magnetic fields, and it's only applicable when the charge distributions aren't changing too rapidly. But it works well for simple electrical circuits. Most of the time we think in terms of electrical potential and don't worry too much about the small excesses and deficits of charge that are producing the potentials.

>> No.5543764

>>5540829

I like that gif

>> No.5544032

http://www.falstad.com/circuit/e-index.html#colpitts

Some visual animations of basic electronics
Check out the electron movements

You can think of electrons like marbles in a tube.The actual electron movement speed may be very slow but you push from one side and they instantaniously move at the other end (with the speed of light) .

>> No.5544045

>>5540940
Thanks for this, not OP but I know absolutely nothing about physics and this is interesting.

>> No.5544049

>have physics test next week on electricity
>haven't done any of the homework yet
I will be monitoring this thread

>> No.5544058

Just out of curiosity, what would a sine graph for a triangle look like? I can't picture it from the .gif

>> No.5544074

If anyone wants some help with anything specific you can add me on skype 'att1llian'
Glad to help ;) Not too long though , need to finish up some projects.

>> No.5545959

>>5544058
>>5540829

How does one make gifs like this?

>> No.5545963

>>5543764
>>5544058
>>5545959
http://1ucasvb.tumblr.com/
this guy is making gifs for wikipedia and stuff. hugely interesting

>> No.5545974

>>5540834
lets say you tried to use the sea/ocean to complete this dc circuit: would the lamp light up? and if it did would be as bright as it would if you replaced the sea with another mile of wire?

>> No.5545976
File: 33 KB, 1658x799, Untitled.png [View same] [iqdb] [saucenao] [google]
5545976

>>5545974 here
>forgot pic

>> No.5545983

>>5545974

The resistance would be very high.. Impossibly high.

>> No.5545991
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5545991

also. when it comes to mains AC plugs, i've always wondered why it matters to designate one wire as neutral and one wire as live with the fuse? with AC are the wires not "switching roles" (insert your localised freq here) times a second?

>> No.5546004

electrical engineers / physicians / chemists... all of them will use other symbolic ideas to describe what electrons do and why. if you want to get a basic idea of what factors are important for elctrical circuits i would go to a library and read the first chapters of a basic book about electrical engineering. if you really want to understand the behavior of electrons you should study physics.

>> No.5546018

>>5545991

Because the live wire is ALWAYS going to be live. If you put the fuse on the neutral, then get confused in your wiring and connect a different neutral to the light, it's no good.

>> No.5546056
File: 38 KB, 1658x799, Untitled.png [View same] [iqdb] [saucenao] [google]
5546056

>>5546018
i re-read that a few times and still don't get it, where does the "different neutral" come into this scenario.

the point I'm making is with AC - my understanding is the current will be going in one direction, and then other, then back in the first direction, then again in the second and so on. given that, how/why can you differentiate between the wires in terms of a 'live' and a 'neutral' ?

>> No.5546071
File: 28 KB, 829x400, 361318605299.png [View same] [iqdb] [saucenao] [google]
5546071

>>5546056

Do you see?

>> No.5546073

>>5546056

In real life it's not as simple as in your drawing. The power line isn't some sort of AC battery. Pull the wires out of a light socket. If you touch the red one, you'll get a shock. If you touch the black one, you won't. The black one only becomes active when it's connected to a red one.

When wiring a house, things become very complicated, with wires running back and forth between switches and light sockets and power points. Most of these are netural, in that they only become active when the proper switch is thrown and they become connected to a live wire from the meter box. It's much simpler to put your fuses on the live wires at the meter box, because you can be certain that any current that flows will pass through them.