Why do magnets attract or repel each other?

In summary, the movement of magnets towards or away from each other is due to electrostatic force and relativity, which turns it into a magnetic force. The direction of motion is explained by electrons with different directions of movement generating different currents and relativity converting it into a magnetic force. The origin of charge itself is currently unexplained.
  • #1
blumfeld0
148
0
If I have one magnet sitting on a table and I take another magnet and bring close to the first one it will move towards the magnet!
This is amazing to me. My question is why does one magnet make another move toward or away from it? what is the origin of magnetic force.
I think it has something to do with QED(thats why I am posting in the quantum forum) -perhaps the exchange of virtual particles and hence momentum but I am not sure.
Is there a simpler explanation? if not can someone elaborate on the virtual particle scenario if that is the correct one?

thank you
 
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  • #2
You are asking two different questions. The first question is "what makes the one magnet move?". That's electrostatic force. But since the electrons are moving, relativity makes the force into a magnetic force. That's all.

The second question is "why does it move AWAY or TOWARD". I don't know the answer to that. I think that is where smarter people start using the acronym QED.
 
  • #3
actionintegral said:
The second question is "why does it move AWAY or TOWARD". I don't know the answer to that. I think that is where smarter people start using the acronym QED.

The electrons have electric charge (unexplained datum*). An explanation for the direction of motion that is effective at the scales of humanly accessible energies is that electrons moving one way generate a different current from electrons moving the other, and relativity as you said makes that into a magnetic force, but differently directed for the two cases.


*There are proposed explanations for charge quantization, but I am not aware of any mainstream explanation for the existence of charge itself.
 

Related to Why do magnets attract or repel each other?

1. What is the origin of magnetic force?

The origin of magnetic force is the movement of charged particles, such as electrons, within a substance. These particles have a property called magnetic moment, which is the combination of their charge and the distance they travel. When these particles move, they create a magnetic field, which is the source of magnetic force.

2. How does the Earth's magnetic field originate?

The Earth's magnetic field originates from the planet's inner core, which is made up of iron and nickel. The rotation of the Earth's core creates a dynamo effect, generating electric currents that produce the magnetic field. This field protects the Earth from harmful solar radiation and plays a crucial role in navigation for animals and humans.

3. Can magnetic force be shielded or blocked?

Yes, magnetic force can be shielded or blocked by certain materials, such as iron, nickel, and cobalt. These materials have a property called ferromagnetism, which means they can align their magnetic moments in the same direction and form a magnetic shield. Other materials, like copper and aluminum, are not affected by magnetic force and cannot block it.

4. How does temperature affect magnetic force?

Temperature can affect magnetic force in two ways. First, increasing the temperature of a substance can cause its particles to move faster and generate a stronger magnetic field. Second, at extremely high temperatures, a substance can lose its magnetic properties and become non-magnetic. This phenomenon is called the Curie temperature and varies for different materials.

5. What is the relationship between electricity and magnetism?

The relationship between electricity and magnetism is described by Maxwell's equations, which state that a changing electric field produces a magnetic field and a changing magnetic field produces an electric field. This relationship is the basis for many technological applications, such as generators, motors, and transformers.

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