What is Magnetism? | Understanding Attraction & Difference from Gravity

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In summary, magnetism is a fundamental force of nature that is generated by moving electrical charges and is related to the electromagnetic field. It is distinct from gravity, which is another fundamental force that acts on particles with mass. Magnetism is responsible for the attraction between magnets and is caused by the alignment of electrons in magnetic materials. It is one of the four fundamental forces in nature, along with gravity, the strong force, and the weak force.
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Tregg Smith
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Can anyone say what magnetism is beyond that it is a field and a property of the electrical nature of atoms? That is why do magnets attract? How is it different from gravity?
 
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Tregg Smith said:
Can anyone say what magnetism is beyond that it is a field and a property of the electrical nature of atoms? That is why do magnets attract? How is it different from gravity?

We do not know the fundamental process by which magnetism emerges.
 
  • #3
But we know for certain it is not at all like gravity!
 
  • #4
Check the quantum theory of paramagnetism about 'magnetism and angular momentum'.
 
  • #5
Magnetism is the component of the electromagnetic force that is generated by moving electrical charges. If you change your speed so that the charges appear to be stationary (imagine running along side them) then the force will appear to be electrical rather than magnetic. For an electromagnet (a wire with current running through it) you could potentially "run along" with the current and instead of seeing a current with a magnetic field you'd experience a charged wire with an electrical field. The relationship between electrical and magnetic forces and velocity is described by Maxwell's equations, and has been known since the 1800s. Because "electric" and "magnetic" fields are just two ways of looking at one thing, depending on your relative velocity, they are considered one, "electromagnetic," field.

On a microscopic/quantum mechanical level the electromagnetic field results from charged particles passing photons back and forth to each other. You usually experience photons as particles of light, which is electromagnetic radiation, but there are photon versions that are purely magnetic or purely electrical, and the version you get depends on your velocity. This is the quantum basis of Maxwell's equations. When particles with opposite charges swap photons they attract each other, and that includes moving charges (magnets). For magnets, instead of referring to positive and negative charge we generally refer to north and south poles, or up and down, but again, opposites attract.

For magnetic materials (fridge magnets, etc.) the magnetism comes from the atoms, nearly all of it from the electrons. The real (quantum mechanical) picture is a weird one, but the electrons behave in many ways *as though* they were little charged spinning balls orbiting around a nucleus like planets around the sun. If charge is spinning or orbiting it's moving, and voila! you have a magnetic field. In most materials all the electrons move in random ways and cancel each other out, so you don't notice the magnetic effect. In magnets though the material properties are just right to make all the orbits align in the same direction, and so they all add up and you say "look, a magnet!"

Electromagnetism is one of the four forces in nature (yep, only four). The force is carried by photons (AKA light particles), and acts on any particle with electrical charge. Charge can come in two flavors, which we call positive and negative. Gravity is another force, and it should be carried by particles called gravitons, which have not yet been detected but which we expect to exist. Just like electromagnetism, gravity has "charge," but it only has one flavor, and we call it "mass." Particles with electrical charge and no mass will ignore gravity but be affected by electromagnetic fields, and vice versa. (Ignoring general relativistic stuff, which is complicated.)

(In case you care: the other two forces are the "strong force" which holds the nuclei of atoms together, and the "weak force," which sometimes breaks them up. Each has it's own version of "charge" and a special particle that carries the force.)
 

FAQ: What is Magnetism? | Understanding Attraction & Difference from Gravity

What is magnetism?

Magnetism is a natural force that causes objects with certain properties, such as iron and steel, to attract or repel each other. It is caused by the movement of electric charges within the atoms of these objects.

How does magnetism work?

Magnetism is caused by the alignment of the electrons within the atoms of a material, which creates an invisible magnetic field around the object. This field can attract or repel other objects with opposite or like charges, respectively.

What is the difference between magnetism and gravity?

Magnetism and gravity are both natural forces, but they work in different ways. Gravity is a force of attraction between any two objects with mass, while magnetism is a force between objects that have a magnetic field. Gravity acts on all objects, while magnetism only affects certain materials.

How is magnetism used in everyday life?

Magnetism is used in many everyday objects and technologies, such as magnets on refrigerators, speakers, and electric motors. It is also used in medical devices, such as MRI machines, and in transportation systems, such as trains that use magnetic levitation.

Can magnetism be harmful to humans?

In general, the magnetic fields produced by everyday objects are not harmful to humans. However, high levels of magnetic fields, such as those found in MRI machines, can cause some health effects. It is important to follow safety guidelines and limit exposure to strong magnetic fields.

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