General Question

s321scba's avatar

What are the OBSERVED differences between electric and magnetic fields?

Asked by s321scba (67points) May 6th, 2011

somehow electromagnets effect “ellectrically charged” material

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18 Answers

Qingu's avatar

A changing magnetic field creates an electric current (a flow of electrically charged material).

A changing electric current, in turn, creates a magnetic field.

gasman's avatar

Electricity and magnetism, once thought to be separate phenomena, were shown to both arise from a property of matter known as electric charge. The unification came in the late 19th Century, succinctly summarized by Maxwell in his famous set of four equations. To a physicist, Maxwell’s equations speak for themselves in the language of vector calculus. As usual in physics, descriptions in layman’s terms always fall short of the deep elegance of the equations themselves.

Electric fields emanate from isolated charges with a property known as divergence, whereas magnetic fields have no counterpart in the form of isolated north or south poles (aka monopoles) but instead have a property known as curl. Varying electric fields give rise to magnetic fields, while varying magnetic fields give rise to electric fields (as already sated by @Qingu) in accordance with the equations.

Maxwell’s equations also predict the existence of electromagnetic (EM) waves, later discovered by Hertz. EM waves bundle both electric and magnetic fields perpendicular to each other, propagating at a constant velocity (also predicted by Maxwell’s equations), later shown to be the speed of light.

EM forces are what hold atoms and molecules together, accounting for all of chemistry. A few modifications are necessary because of quantum theory.

RocketGuy's avatar

An electric field acts perpendicularly to a magnetic field.

s321scba's avatar

quiqu’s comment: a magnetic field attracts or repels electrons and protons, a magnetic field can alter the properties of iron to make another magnet, without changeing polar orientation

sciences should explain not complicate, if you can’t proove it to laman (any reletively sain person) then either the information or the presentation needs fixing
try to include obseved examples not neccesarily for explaining but for proof for this post try to avoid using ideas un challenged

Qingu's avatar

Magnetic fields don’t attract or repel electrons and protons, not exactly. Electric fields do.

And sometimes science is complicated. People thought the sun revolved around the earth once. That seemed simple and obvious and a layman can understand it. But it was wrong. Unfortunately, magnetism gets pretty complicated pretty fast; you have to get into quantum mechanics to understand it at a fundamental level. Would you like me to try to explain quantum mechanics?

s321scba's avatar


only the first “paragraph” was directed solely at you the rest was a general comment for this question

Qingu's avatar

Okay, so here’s quantum mechanics (I, a non-physicist, am probably going to massacre this).

You can “zoom in” on your hand to see the cells that make it up. Those individual cells follow certain rules that, when working together, make your hand work a certain way.

Those cells, in turn, are made up of even smaller atoms and molecules. These units also follow certain rules that, working together, govern the way that cells work.

Zoom in farther, and you can see that the atoms are made up of even tinier units. In the center is a nucleus made of neutrons and protons. And those neutrons and protons are made of even smaller units, quarks. Around the nucleus is a whirling cloud of electrons.

At this level of “zooming in,” the rules that things follow start to look pretty weird. For example, you can’t say that an electron actually exists at any given place and time. Their existence is “smeared out” into waves—waves of probability. You can only tell the probability of an electron existing at any given place and time. Likewise for the quarks inside the nucleus. That seems weird, but we know for a fact that it’s true. The concept of “existence,” of something taking up space and staying there over time, simply does not work at this level of reality—just like your concepts of taste, smell, and pain don’t work at the level of cells or atoms.

Now. Each one of these subatomic particles—electrons and quarks—has certain properties associated with it. Each one has a mass, an electric charge, and a spin. You probably know that electrons have a negative electric charge. But their spin is also important, because it’s closely related to magnetism. Basically, spin is what you’d think—it’s angular momentum, the same thing that a spinning top has. But at this level of reality, the spins only come in “chunks,” or “quanta”—just like charges.

So you have all these electrons—and they are all spinning at the exact same speed. But they’re not necessarily spinning in the same direction. Picture a bunch of spinning tops all floating in space, rather than laying flat on the floor. They all spin at the exact same speed, but they can be tilted any which way. (Except, even more complicated, these tops don’t even “exist” at a precise location and time—because electrons are at the level of reality where such concepts don’t make sense).

With me so far?

RocketGuy's avatar

You can set up an electric field by connecting parallel, horizontal plates to a battery: + to the upper plate, – to the lower plate. Charged particles will be attracted to one plate or the other. The direction of movement will be parallel to a line drawn between the plates, either upwards or downwards.

You can set up a magnetic field by placing two magnets with N and S pole facing each other, but not touching. If the upper pole is N and the lower pole is S, charged particles shot into the field will turn left or right! The direction of movement will be perpendicular to the line drawn between the poles.

s321scba's avatar

i understand what you are saying but not in relation to reality.
what situation or explanation is given for electrons and other subatomic stuff being a field or spatial force carrier
appologies for not answering sooner

RocketGuy's avatar

@s321scba – I have no idea what you are trying to say. Please describe step by step.

s321scba's avatar

the idea that some things are fields or waves in specific opposition to particles

Rarebear's avatar

@s321scba What you’re talking about is quantum mechanics, not electromagnetism.

s321scba's avatar

i’ve heard lots things saying electric fields and magnetic fields are different, but i don’t think i have ever heard of any actual difference. according to quinque quantum mechanics explains it. i wanted to find proof,given by real life experiences and stated that i didn’t see any,
in his opening explanation he referred to electron wave theory which i thought, would be reletive to the line of evidence, and wanted to know of demonstrative proof (a result coinciding with the claims)

Rarebear's avatar

What? Wait what? Quinque quantum mechanics? What is that?

In answer to your question, again, electricity and magnetism are two aspects of the same force. As @RocketGuy said, they move perpendicularly to each other as the wave propogates. If you want to learn how electricity and magnetism are aspects of the same force, just look up the function of an electromagnet.

s321scba's avatar

quinque was one of the comentators 1st 5th and 7th

Rarebear's avatar

No, it was @Qingu not quinque.

Qingu's avatar

@s321scba, if I understand your question, you’re asking why quantum phenomena are fields and waves as opposed to particles, yes?

First of all, quantum phenomena can often be treated as waves OR particles (see wave-particle duality). So I’m not sure why you’re asking this question.

Why is quantum stuff this way? The short answer is that it just is. We’ve observed it (see double-slit). Quantum mechanics is the most accurate branch of science. If quantum phenomena did not act like both waves and particles, none of the equations that govern it would work. They do; we’ve observed them fitting the equations to an insane degree of accuracy.

But that’s probably not satisfying. And I don’t blame you for wondering “why.” So let’s think about what a wave and a particle actually are, in an abstract sense. At the level of our existence, a wave and a solid chunk of something (a particle) obviously seem very different. Waves overlap; billiard balls smack together.

But look deeper. Why do billard balls smack against each other? Because they’re solid. What is a solid? It’s a crystalline arrangement of atoms. Those atoms could just as easily be a liquid… and their arrangement would then be governed by wave dynamics, not particle dynamics.

What’s more, waves can act like particles. The best example is a solitary standing wave, called a soliton. Solitons occur in water as these single waves that move around much like particles do. And if two solitons hit each other, the interference between them resembles the way “particles” transfer energy to each other.

So if you look deep and think abstractly, the boundary between “wave” and “particle” is not so clear cut. These categories only appear separate because of our everyday experience.

And that’s the problem with looking for proof with “real life experience.” Our real life experience does not tell us much about the behavior of fundamental particles and fields, much like how it doesn’t tell us much about the behavior of cellular structures. We know how cells behave; we know a lot about what causes diseases on a cellular level. But that’s because we looked at cells through a microscope. If you tried to figure out how diseases work based on “everyday experience” you would probably not even know that cells exist, and you might (as our ancestors did) conclude that demons caused them.

s321scba's avatar

but it’s real life experiences like the double slit experiment that are given as evidence

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