How do magnets work and why are they reacting different to some sort of metals?
The whole Earth has a so-called dipole moment with a south pole and a north pole. The picture shows the magnetic field lines that wave from the South Pole (yellow) and towards the North Pole (blue).
Everyone who has played with Brio trains would remember for sure that the magnets of the trains get sticked to each other when two different ends come closer.
If it’s the wrong ends, the magnets repel each other and the wagons are pushed away.
We adults have to be ready to answer the questions:”How do magnets work?” and how in the earth could the same poles push each other and different poles attract each other.
Magnets: How do they work?
All the building blocks of the atoms are magnetic. That is, both the core particles (neutrons and protons) and the electrons themselves act as small rod magnets with a dipole torque.It is an inherent feature of the core particles that they are magnetic to some degree.
The Earth’s magnetic fields can be used with a good approximation to describe what a magnetic dipole moment is. The Earth has two magnetic poles – the North Pole and the South Pole. Between the poles. Magnetic waves flow through magnetic fields from the South Pole and move in a curve towards the North Pole.
A compass will always adjust to the magnetic currents and therefore point towards the North Pole, no matter where on Earth you are.
Electrons provide magnetic atoms
The electrons are organized around the atomic nucleus in such a way that they match and equalize each other’s dipole momentum. It removes the magnetic properties of the two electrons together.
However, in some elements, such as iron, it is not possible to pair all the electrons. Here the free electrons will give rise to a dipole moment for the entire atom and thus iron becomes attractive to magnets.
How to create a magnet
In a solid material, the atoms are organized in a well-defined grid. Here the atomic magnetic dipole moments can either be parallel where the magnetic field currents point in the same direction, or antiparallel where they point in different directions.
If they are parallel, a ferromagnetic arrangement will occur, which means that the entire material becomes magnetic with a dipole moment.
However, if the magnetic fields of atoms are organized antiparallel, an antiferromagnetic arrangement will arise, in which the magnetic fields of the atoms dissolve each other and the material will not be magnetic.
Intermediate can also occur. This is called ferromagnetism and results in weaker magnets.
Looking at the individual atoms, they only have weak magnetic fields. To create a true magnet, all the magnetic fields should point in the same direction. This creates ferromagnetism that is very powerful.
Atoms align themselves with the magnetic fields
Magnets often consist of alloys of metals that are arranged ferromagnetically, so that all nuclear magnetic fields point in the same direction. This brings all the small dipole moments together in one large dipole moment across the entire magnet.
Around the magnet there is a magnetic field moving around the magnet in closed lines. Herein all atoms will align so that their own dipole momentum will follow the magnetic field. This means that the direction of the dipole moment will be the same: from the north pole to the south pole – as in the Brio trains.