# The Naked Scientists Forum

### Author Topic: What is electric charge? What is magnetic force?  (Read 4637 times)

#### Robro

• Full Member
• Posts: 69
##### What is electric charge? What is magnetic force?
« on: 28/02/2010 20:08:14 »
Interested in various ideas...anybody?
« Last Edit: 03/03/2010 18:30:11 by Robro »

#### LeeE

• Neilep Level Member
• Posts: 3382
##### Re: What is electric charge? What is magnetic force?
« Reply #1 on: 28/02/2010 23:37:23 »
No ideas (that I'm prepared to share).

Damn good question though.

#### fontwell

• Jr. Member
• Posts: 39
##### What is electric charge? What is magnetic force?
« Reply #2 on: 23/03/2010 15:22:26 »
When I was studying electronics 25 or so years ago we had to get a book called something like Magnetism For Electrical Engineers. In the introduction it offered advice on how to respond if we were ever asked the question "What is electricity?" It suggested we should reply "I don't know" for the reasons of this response being both brief and true.

I therefore put it to you that Charge is a unit of electricity

#### Farsight

• Sr. Member
• Posts: 396
##### What is electric charge? What is magnetic force?
« Reply #3 on: 23/03/2010 15:51:07 »
Good tip.

I know.

#### namaan

• Sr. Member
• Posts: 195
##### What is electric charge? What is magnetic force?
« Reply #4 on: 23/03/2010 16:41:08 »
Well, since I'm a nobody and have nothing to lose I'd say an electric charge is an arbitrary definition by the universe of a very specific quantum arrangement of matter. This definition defines a field that affects other matter that is sufficiently close and also possesses the appropriate 'charge' (positive/negative).

And magnetism is also an arbitrary definition by the universe of a moving charge. One might say magnetism is an accountant for kinetic energy since all matter is ultimately composed of charges given the appropriate scale.

Yes the above use of 'arbitrary' just might be the ultimate cop-out...feel free to destroy these ideas

#### Soul Surfer

• Neilep Level Member
• Posts: 3345
• keep banging the rocks together
##### What is electric charge? What is magnetic force?
« Reply #5 on: 24/03/2010 18:59:56 »
Presumably our questioner is looking for a physical definition for the origin of electrical charge in a similar way to the way gravitational force is described as a distortion in space time.  This is interesting and some thought on this is worthwhile.  the string theorists describe it in terms of distortions and shapes in other dimensions.    These are probably the most accepted at the moment

magnetism can be described in terms of the action of relativity theory on moving electrical charges and so has a clear physical origin.

Now gravity is also expected to have  a gravitomagnetic effect when moving masses interact but the direct observation of this  sometimes called frame dragging is very difficult but is currently being attempted using gravity probe b so there is this clear parallel between electrical and gravitational "charge"

my personal guess that I have always held is that electrical charge comes from some way in which space time is screwed up to form particles although precisely which way it is screwed up I do not know.

#### LeeE

• Neilep Level Member
• Posts: 3382
##### What is electric charge? What is magnetic force?
« Reply #6 on: 25/03/2010 16:56:53 »
Yeah, I favour some form of space-time mangling too, but am equally unable to define/describe/explain it.

Mind you, one issue with space-time models of electromagnetism is that it's difficult to explain both attractive and repulsive forces without incurring time reversal somewhere along the way.

Oh, and furthermore, if you do manage to explain electromagnetism in terms of space-time then anti-gravity starts to look likely too.
« Last Edit: 25/03/2010 17:01:07 by LeeE »

#### yor_on

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##### What is electric charge? What is magnetic force?
« Reply #7 on: 28/03/2010 02:09:55 »
I can give some guesses :)

'Electrical Charge' have to move at 'C' and when it moves we seem to call that a 'current'. If we take the 'push model' and think of a tube wherein you have balls rolling, then, whatever 'charge' might be it will be similar to what hitting one of the balls will create on that other side of the tube where another ball lies, almost ready to fall. So, when I 'push' the ball at my side, the one over at the other side will fall out even though the ball (electron) 'pushing' still is on the other side´. That as in AC (Alternate Current) the electrons may be ' wiggling' but not moving, and with only the 'current' flowing through. In DC on the other hand we do have a clear propagation/movement of electrons.

Another way of looking at is this. " Electric charge is a component of atoms. In other words, after we have broken an object into molecules, and broken the molecules into atoms, when we break the atoms apart we discover particles of electric charge. Charge is material, it is like atoms but it is one step lower than atoms. Most science textbooks tell us that solid objects are made of atoms. It is also valid to state that solid objects are made of electric charge. Objects are made of equal quantities of positive and negative charge, and objects stay together because of the attraction between the quantities of opposite charge inside them. Chemical bonds are electrical in nature."

The weight here is on this statement "It is also valid to state that solid objects are made of electric charge." We are made of 'charge' in other words, and when those atoms move the positive and negative charges along together, we then call it "physical motion." Since matter is composed of charge-carrying particles, all physical motion is a motion of charge, but in most cases both the negative and the positive charges move along as one. When opposite charges move separately, THAT is when interesting things occur.

Opposite charges moving along together are "mechanical", while opposite charges moving differently are "electrical." If the negative charge in an object should start moving while the object's positive charge stays at rest, then we call that motion an electric current. The words "electric current" mean the same as "charge flow.""

A bit hefty perhaps but as I too wonder what electrical charge is :)

And lastly an analogy from Corvidae trying to describe the idea of charge to me.

===Quote=

Maybe a mammalian analogy would be more enlightening. Think of a conductor as a long field of gopher holes. Every hole is an atom with it's own set of gophers. There is exactly enough room in each gopher hole for 29 gophers (copper gopher holes). And every gopher hole needs 29 gophers to keep itself maintained.

Along comes farmer Battery and he shoots a gopher on one end of the field and releases one gopher on the other end of the field. The gophers in the hole where one was shot, now need an extra gopher. However the new gopher is WAY on the other end of the field. It's much easier to steal a gopher from a nearby hole. So the gophers charge (Yup, the mystical charge) over to the other hole (atom), and steal a gopher (electron). Now that gopher hole needs a new gopher and does the same thing to another hole that's closer to the new gopher.

Rinse and repeat until you get greasy grimy...no wait wrong analogy..Until you reach the far end of the field, and the new gopher gets pulled into the nearest hole that's missing a gopher.

In the end, the new electrons (gophers) don't actually move very far, since there is always a nearby atom needing a negative charge. For an electron to actually move all the way down the field, it'd take a whole lot of gopher killing.

If you want to get really confused about it. Try figuring out the actual electron flow involved in receiving an FM radio signal.

=End of Quote.

With lot of thanks to bm1957 that laid the groundwork for helping me narrowing down what 'charge' might be.

==Quote=

Electrons have negative charge and protons have positive charge, but it's only the electrons which move. When one electron moves from where it was, it leaves a 'virtual' positive charge there. This is referred to as a 'hole'. The movement of negative electrons in one direction is entirely equivalent to the movement of positive holes in the other direction. Protons very rarely move in an electrical circuit (except maybe when ions are conducting, off point though.).

The transfer of energy (according to currently accepted theory) is entirely through the transfer of photons between electrons; an electron receiving a photon becomes excited and jumps to a higher energy level. When it falls back down to its original energy level, it releases a photon. This is the proposed mechanism for the electromagnetic force. Photons can easily transfer across a junction between the socket in the wall and the plug which is inserted into it, as can electrons flow both ways (equivalent to positive holes moving in opposite directions to the electrons) across the junction. This is also true if it was your finger which went into the socket and completed the circuit to ground.

Back to AC. The electrons are still moving, but the net flow rate is zero. They go backwards and forwards on the spot, about 20 times a second (at 50Hz). The distance they go backwards and forwards depends on the voltage. The average DC current being transferred is zero. If you somehow tweak your 'receiver' to flip every cycle (as motors and electronic circuits can), then you extract the energy of the 'positive DC electrons' then flip, and extract the energy of the 'negative DC electrons'. Since you flip in between, the energies add together because they were 180deg out of phase before the flip, and are now exactly in phase.

==End of quote=

Links: WHICH WAY DOES THE "ELECTRICITY" REALLY FLOW? which is very likeable to me, explaining it simply and succinctly (my level sort of:). And for those demanding a more physical answer :) hyperphysics.
==

One of the most important lessons we can draw here is that it's not right to say that the electrons 'flow' and polarity (- or +) have anything to do with charge. It doesn't matter if electric currents will be a flow of positive or negative particles in any direction. " Actually, in many situations electric currents are a flow of genuinely positive charges. In other situations the flows are negative particles. And sometimes the currents are both positive and negative particles flowing at once, but in opposite directions. The true direction of the flowing charges depends on the type of conductor."
==

Which in fact make me hate the schools I got taught by. Both for missing the first idea (electron flow) as well as the second. It's a sad thing when I only find what's true by learning like this and not by those school giving me a diploma saying that I 'understand' ::))

Sh*.
« Last Edit: 19/04/2010 20:32:44 by yor_on »

#### The Naked Scientists Forum

##### What is electric charge? What is magnetic force?
« Reply #7 on: 28/03/2010 02:09:55 »