Can Someone Explain The Power Of Magnetism?

[billt460]

Magnetism is fascinating. Most of us remember at some point in grammar school, having a science teacher using magnetism to explain the positive and negative parts of the Earth's magnetic field, or some such. Usually using a magnet with iron filings sprinkled on to a piece of paper to recreate a model of it.

But they never really explained it's invisible power, or how it actually works. Or where the actual physical force it applies to objects, comes from?... Without any physical connection or link between the 2.

How can something, (besides gravity and / or centrifugal force), exert physical force on to something without any type of direct link? What got me thinking about this, was when I was going through my tools and stuff a while back, I found a really strong pair of Neodymium magnets I had from years ago.

I could barely get them apart. My wife saw me struggling, and asked me how they could be so stuck together? I didn't really have an answer. Do any of you?

 

[Urshurak776]

 

[MVAR]

Preparing a shift turnover report now so no time to respond properly. If it's a quiet night coming back in tonight, I'll put something together, but it'll be geared more towards electromagnetism.

 

[spackard]

What really drives physicists nuts is how magnets have two poles only, you break a magnet into 2 pieces, and suddenly each piece has two poles. Ad infinitum.

 

[cptbarkey]

Insane Clown Posse couldnt figure it out either

 

[MVAR]

Here's something quick from EPRI:

2.4.3 Magnetism & Magnetic Fields
Electricity and magnetism are closely related subjects. An understanding of
magnetic fields is necessary before AC impedance can be described. This section
examines the cause and effects of magnetism and magnetic fields.
Sources of Magnetism
Magnetism is a property of matter associated with moving charges. The moving
charges may be within the atomic structure of the materials as in magnetized
pieces of iron or steel. These type materials are called permanent magnets.
Magnetism also arises any time there are moving charges associated with an
electric current. For example, an electric current flowing through a straight
conductor or a coil produces a magnetic field. The magnetic field is generally
much stronger for a coil because of the number of turns of wire in which the
current flows. If the coil is wound around a core made of magnetic material,
an electromagnet is created.
Magnetic Fields
A field can be thought of as a force distributed over an area. For example, gravity
is a field. The earth’s gravitational field can be thought of as lines of force that
extend outward from the earth’s center, and weaken with distance. Any object
within the earth’s gravitational field experiences the force of gravity pulling it
toward the earth. Similarly, magnetic fields can be viewed as lines of magnetic
force. Any other magnet placed within a magnetic field will experience a
magnetic force.
The geometry of magnetic fields varies depending on the source of the field as
illustrated in Figure 2-22. Permanent magnets have two poles designated north
and south. The lines of magnetic force run by convention from the north pole to
the south pole. The Earth is a permanent magnet with a magnetic field that can be
detected with a compass.
The magnetic field due to a current in a straight conductor is concentric about the
conductor as illustrated in the right side of Figure 2-22. The intensity of the
magnetic field, due to the current, decreases as the distance from the conductor
increases. The magnetic field due to a coil is similar to that of a permanent bar
magnet. This type of magnetic field is illustrated in the left of Figure 2-22.
Magnetic fields can be confined within magnetic materials such as the iron in a
transformer’s core. In other words, if a magnetic field is set up in an iron
structure, the lines of magnetic force tend to be confined to that structure.
Figure 2-23 contains a simplified transformer core. The core is a rectangular iron
doughnut. If a wire is wrapped around the core and current is passed through it as
shown, a magnetic field is created in the core as illustrated. Because iron is a
better magnetic material than air, most of the magnetic field remains in the core.

Electromagnetic Induction
If there is relative motion between a magnetic field and a conductor or if there
is a change in the magnetic field linking a conductor for some other reason, an
electromotive force⎯or voltage⎯is generated. This voltage causes current to
flow if an electrical circuit is formed. This concept is called electromagnetic
induction. Electromagnetic induction is a very important principle as it is the
basis upon which many types of power system equipment (transformers,
generators, etc.) operate. Figure 2-24 illustrates the concept of electromagnetic
induction.

The relative motion between the conductor and the magnetic field may be due to
physical motion of the magnetic field or the conductor or both. The relative
motion may also be due to changes in the magnitude or direction of the magnetic
field. In other words, if a conductor is placed in a fluctuating magnetic field, a
voltage is induced in the conductor.
The magnitude of the induced voltage is dependent on the alignment between the
magnetic field and the conductor. For example, if a conductor is passed through
the densest part of the magnetic field, a large voltage will be produced. However,
if the conductor is passed through the weakest part of the magnetic field a smaller
voltage will be produced.
Magnetic Fields and AC Power Systems
When DC current flows through a conductor a constant magnetic field is created.
When AC current flows through a conductor, a variable or alternating magnetic
field is created. The variable magnetic field alternately builds and collapses
as the AC voltage wave builds and collapses in its normal cycle. This constantly
changing magnetic field results in an induced voltage in the conductor. This
induced voltage is referred to as a “back emf”. The voltage due to the back emf
opposes the original voltage that caused the current to flow. The result is to delay
the current flowing in the conductor.
This delay or lag in the current due to a back emf is one of the reasons why
current and voltage are generally out-of-phase in an AC system. The effect is
larger with coils, such as those in a transformer, because of the strong magnetic
fields associated with coils. In the next section, this concept is used to explain the
inductive component of the impedance of an AC circuit.

OK. Shift change is starting. I'll add more tonight.

 

[Astro14]

Magnetism - like gravity - transmits the force over a distance and we can’t “see” it. James Clerk Maxwell was among the first to describe the relationship between electricity and magnetism. The force varies, of course, based on distance, and on the properties of the magnet, or the flow of the current. To understand the “field” that is created takes a bit of math, but videos and simple descriptions exist. I would do a bit of research by searching for physics lectures, or physics explained, on YouTube, so that you can experience the diagrams and descriptions visually.

 

[burbguy82]

Try the following as to the "how and what"

https://science.howstuffworks.com/magnet.htm

As to the "why":

The laws of magnetism where written during the creation of the physical world. It doe serve an essential purpose, lest it would not be so prevalent. Stuff has to stick together.

What I dont understand is on the atomic level whereas electrons are negative..........if atoms stick to each other, and all electrons are negative, I would assume that they would repel each other.

So maybe the nucleus is more powerful than the electron in an atom, and therefore the balance is held? Not sure. But this does not explain positive or negative ions. I am not sure an atom even looks like this anyway, as to my understanding one has never been seen, as they are too small. The above drawing of an atom, methinks is a theoretical drawing, the ones we see in school. But if you but two of these together they should repel or attract, but that does not seem to be the case.

Great subject matter for us peons to argue about.

 

[Elkins45]

Gravity is the force that really messes with my head. It acts instantaneously at infinite distance, and it isn’t polarized: unlike magnetism, gravity only attracts.

 

[Elkins45]

Try the following as to the "how and what"

https://science.howstuffworks.com/magnet.htm

As to the "why":

The laws of magnetism where written during the creation of the physical world. It doe serve an essential purpose, lest it would not be so prevalent. Stuff has to stick together.

What I dont understand is on the atomic level whereas electrons are negative..........if atoms stick to each other, and all electrons are negative, I would assume that they would repel each other.

View attachment 260924

View attachment 260925

So maybe the nucleus is more powerful than the electron in an atom, and therefore the balance is held? Not sure. But this does not explain positive or negative ions. I am not sure an atom even looks like this anyway, as to my understanding one has never been seen, as they are too small. The above drawing of an atom, methinks is a theoretical drawing, the ones we see in school. But if you but two of these together they should repel or attract, but that does not seem to be the case.

Great subject matter for us peons to argue about.

Electrons do repel each other, but at the same time they are attracted to the positive charges in the nucleus. In a way it’s like the way the Earth is attracted to the Sun yet inertia makes it try to fly away in a straight line. The end result is a stable orbit where the Earth is continuously “falling around” the Sun.

With electrons and chemical bonding it’s somewhat more complex because there are multiple electrons orbiting the nucleus. To accommodate this they arrange themselves in very specific orbital shapes at distinct distances. There is some sort of “natural desire” to fill each of these orbital levels with a certain number of electrons. As an example consider H and O making water. Oxygen has six electrons orbiting in a shell that really wants eight, so it uses one from each hydrogen to complete that electron shell. This desire to complete the p orbital is more powerful than the repulsive force because of the complex orbital shapes that keep them at maximal distances from each other. It also explains why water is H2O not HO or H3O.

For years the existence of distinct orbitals was considered just a really effective theoretical model but sometime in the last 30 years or so actual images of individual atoms were resolved by the use of a scanning tunneling electron microscope. This verified the hypothesized dumbbell shape of the P orbital, among other things.

 

[TomYoung]

What really drives physicists nuts is how magnets have two poles only, you break a magnet into 2 pieces, and suddenly each piece has two poles. Ad infinitum.

This does not drive any physicists nuts.

 

[Leo99]

I think that very few people truly understand electromagnetism with AC. We can describe it and measure it and make use of it. We can wind coil of wire to magnetize them to make electric motors, but to truly understand it, maybe only mad scientists like Maxwell and Tesla. I studied AC electricity in college. It gets crazy. You need imaginary numbers with the square root of -1 to solve the equations.

To understand electricity, we typically talk about current flow but does it really flow?

 

[burbguy82]

but at the same time they are attracted to the positive charges in the nucleus

That is what I was saying.

actual images of individual atoms were resolved by the use of a scanning tunneling electron microscope

I understand this to be extrapolation, and not an actual image.

 

[Number_35]

Gravity is the force that really messes with my head. It acts instantaneously at infinite distance, and it isn’t polarized: unlike magnetism, gravity only attracts.

I had long assumed that gravity's effects were instantaneous, but heard somewhere recently that no, gravitation was limited to the speed of light (C).

But I don't actually know which of these positions is true. Any physicists here?

 

[Leo99]

I had long assumed that gravity's effects were instantaneous, but heard somewhere recently that no, gravitation was limited to the speed of light (C).

But I don't actually know which of these positions is true. Any physicists here?

Google says gravity waves travel at C. Newtonian gravity is instant but Einstein's General Relativity corrected that to C.

 

[JimPghPA]

Gravity is the force that really messes with my head. It acts instantaneously at infinite distance, and it isn’t polarized: unlike magnetism, gravity only attracts.

Not instantaneously. It travels at, or very close to, the speed of light. The time it takes gravity to travel has been observed by the detection of gravity waves from the colision of 2 black holes and the time delay that gravity wave took to travel the huge distance before arriving on earth. Essencially, the gravity wave arrived at the same time when the light from that same event also reached earth.


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As for magnetism, most people have no idea about how the fields of magnets are present, from even a small magnet.

 

[Elkins45]

Not instantaneously. It travels at, or very close to, the speed of light. The time it takes gravity to travel has been observed by the detection of gravity waves from the colision of 2 black holes and the time delay that gravity wave took to travel the huge distance before arriving on earth. Essencially, the gravity wave arrived at the same time when the light from that same event also reached earth.


---------------------


As for magnetism, most people have no idea about how the fields of magnets are present, from even a small magnet.

I learned something today. I had thought gravity waves were just hypothetical.

If gravity is a wave does it undergo refraction or reflection? Can two gravity waves cancel each other through interference? <—-now there’s an interesting thought.

 

[burbguy82]

It acts instantaneously at infinite distance

Does it?

 

[Elkins45]

Does it?

Apparently I was only half right.

 

[MRC01]

Like any complex physics phenomena, understanding of magnetism is multi-layered.

How Stuff Works has a good explanation: https://science.howstuffworks.com/magnet.htm

Another good place to start is what causes the Earth to have a magnetic field. Earth's core is hot, and the Earth is spinning, causing liquified metals like iron and nickel to flow. These flowing metals create electric currents that create a magnetic field. But not all planets have a magnetic field - for example Mars. It used to, but doesn't anymore. Wikipedia has good articles on this.