What does electricity & magnetism travel through

[taybot]

I understand that the electromagnetic field and light are tied together, and they all travel through big groups of photons and they all travel at the speed of light. And I get that light travels through empty space.

But I am wondering what does electricity and magnetism travel through?

Sound travels through air, light travels through empty space, but what about electricity and magnetism?


Thanks!

 

[Gordianus]

Electromagnetic fields don´t require a medium to support a wave. This perplexing property puzzled brilliant minds for many years. They sought that medium and called it "ether". This medium was supposed to have extremely strange mechanical properties. In 1885 Michelson and Morley found ether may not exist. In 1905 Einstein killed its notion when he published the SR.
The light you see coming from the sun has made a long journey through the vacuum. I still find "strange" this behavior, but if you focus on Maxwell´s third and fourth laws, you´ll find how the electric and magnetic fields interact in such a way to support the wave.

 

[taybot]

I knew that was how it worked with light but I didn't realize it is the same way with electricity and magnetism. So none of them need a medium, they all travel through empty space.

Which make sense since they are all part of the same field anyways.

Thx!

 

[threadmark]

Light consists of a magnetic field and electric field. The photon is what carries light and magnetic fields. Because photons have zero mass it travels at the speed of light. Sound is not like or should be theorized anything like light. Sound isn’t a particle that travels.

 

[Rajini]

Hi,
sound (wave) travel through any solid.
Sound should be just waves!
phonons are just sound wave.

 

[Feldoh]

Yes, but unlike photons phonon's are not really actual particles. We treat them as such but there is no real phonon particle.

 

[LostConjugate]

Yes, but unlike photons phonon's are not really actual particles. We treat them as such but there is no real phonon particle.

Is a photon a real particle either? Just because we can attribute a momentum too it does not mean it is for certain a particle. The same way we can attribute a frequency to the electron but it does not make it for sure a wave.

A photon could just be thought of as the smallest change in velocity in the electric field (for a given frequency). Where velocity is the change of position of the field perpendicular to the direction of travel, not the velocity c of the electric field.

You get p = h/wavelength. It doesn't mean it is a particle, it just has relativistic mass because it has the potential to apply a force on an electron.

 

[Feldoh]

I thought someone might bring that up. However at that point you're just being picky.

You could make the argument is anything a real particle? The answer is of course in the definition.

What I meant is that, comparatively, looking at the objects we typically label as particles it doesn't seem to far-fetched to see a lot of differences between phonon's and things we typically attribute to being particles.

 

[LostConjugate]

What I meant is that, comparatively, looking at the objects we typically label as particles it doesn't seem to far-fetched to see a lot of differences between phonon's and things we typically attribute to being particles.

Well I don't know. Is a phonon not just the smallest change in the velocity of air for a given frequency?

 

[Antiphon]

In a diode the hole is just as real as the electron. It's not a fundamental quantum particle, it's a "synthetic" one. But it's very real.

As to the OP, there's no atomic medium that supports light the way atoms support sound waves. But it's oversimplifying to say there's no medium supporting electromagnetic waves.

Space itself is the medium. The trajectory of light follows the curves of spacetime, the medium through which light travels.

 

[thedore]

If you want to learn more i suggest you google the following

mitopencourseware

They have about 1900 lectures

 

[Gordianus]

The OP, I believe, addressed the subject from a classical point of view.
Then, the thread strayed away with the inclusion of some elements from QM. Many of those posts are confusing and do not clarify the original question because they trudge into complex questions.
I´d like to clarify to points:
A phonon isn't the smallest change in velocity of air.
As far as i Know, neither classical nor QM theories requiere a medium tu support electromagnetic waves. If I say electromagnetic waves travel in space it doesn´t follow space is the supporting medium

 

[Antiphon]

As far as i Know, neither classical nor QM theories requiere a medium tu support electromagnetic waves. If I say electromagnetic waves travel in space it doesn´t follow space is the supporting medium

The theories don't require it but that's because those theories don't adress underlying mechanisms. And no it doesn't follow that space is the supporting medium of electromagetic waves just because you say it. You'd need to say something much more interesting like perhaps this; the equations of general relativity when formulated in 5 dimensions reduce to 4-dimensional spacetime together with Maxwell's equations.

 

[MaterSammichM]

So...can electricity be made to travel along a sound wave?

 

[Drakkith]

So...can electricity be made to travel along a sound wave?

A sound wave is the result of a collective movement of many many particles. Since air is generally NOT a good conductor, the only way to make a current travel through the particles would be to ionize them, which would impart lots of energy into them and disrupt whatever sound wave happened to be propagating.

Replace the air with a conductive fluid, and sure. If I make waves in my bathtub a current can still travel through the water.

 

[MaterSammichM]

Hmmm...I thought air was a better conductive fluid than water...?

 

[Drakkith]

Hmmm...I thought air was a better conductive fluid than water...?

Definitively not! Not only is the density of air very low, which hinders current, the molecules in the air don't easily support a current anyways. PURE water is not a good conductor either, but almost all water contains enough impurities to make it a decent conductor.

 

[Gken]

Are photons a medium which sound waves may travel through?

 

[FireStorm000]

Are photons a medium which sound waves may travel through?

Photons aren't really a medium in that sense. They are better thought of as a type of energy than as a type of matter. Even if they weren't, the fact that photons travel at c means they are incapable of supporting a mechanical wave.

On the subject of the OP, I almost think of it as the magnetic field being the medium of the electric field and visa versa. It is the existence of one (and the fact that it's time-changing) that supports the other in EM waves.

 

[Claude Bile]

...light travels through empty space, but what about electricity and magnetism?

Light is electricity and magnetism.

So in essence, you answered your own question.

Claude.

 

[Mastaan]

But I am wondering what does electricity and magnetism travel through?

Sound travels through air, light travels through empty space, but what about electricity and magnetism?

- Electricity by it self needs a conductive path to travel. Electricity is the flow of electrons from one atom to the next in a chain. Think of it as small tiny balls in a pipe hitting each other and forcing the ones in the end to leave.

Magnetism it self can't travel. You can have a magnetic field. Like permanent magnets or electromagnets made with coils, have a magnetic field around them. When electrons move at a constant speed they form a static magnetic field.

But what happens next is amazing, when u start changing the speed of the electron and move it back and forth, like alternating current(AC), it produces an alternating magnetic field. And changing magnetic field induces a changing electric field. And they keep coupling in this way traveling forward. And this is your electromagnetism, bounded together, including light, xrays, radio waves, your wifi, and cell phone, all work the same way.

This is how transformers works, but now think about the wire on those electric poles carrying AC current, so don't they produce an alternating magnetic field, and thus producing an em wave ? why don't we see this em wave coming out of the wire?

 

[Naty1]

Electricity in everyday use requires atoms with loosely bound outer electrons...called conduction electrons...so they can move along easily from atom to atom ...we say such a material is a good conductor because electricity moves easily...without much power...But you can also force electricity through a poor conductor, like air, by increasing the voltage forcing outer electrons to come loose...ionizing the atom as in air with a spark plug or lightning in a lightning storm.

But you can also have an electromagnetic wave...in free space, like sunlight, that does not require a conductor of any sort. Light is just the portion of the electromagnetic specturm that happens to be visible via sight.