You must have played with magnets when you were a child. They can act like magic to hold metal objects such as nails, keys, scissors, and can also be used to make useful things such as compasses, speakers, and electric motors. But do you know why magnets can attract iron? Where does its magnetic force come from? Today, we will uncover the mystery of magnets and give you a deeper understanding of this magical substance.

Firstly, we need to know that magnets are a special type of metal, mainly composed of elements such as iron, cobalt, and nickel. The atoms of these elements have a special property that they themselves possess magnetism. This is because their atomic nuclei and electrons are constantly rotating, like tiny electric currents, creating a weak magnetic field. This magnetic field generated by atoms is called atomic magnetic moment.

If all atoms in a substance are randomly arranged, their atomic magnetic moments will cancel out each other, causing the substance to have no magnetism. However, in certain substances, such as iron and cobalt (ferromagnetic materials), due to their unique electronic structure, their atomic magnetic moments can be arranged according to certain rules, forming small regions called magnetic domains. In each magnetic domain, all atomic magnetic moments point in the same direction, resulting in a strong net magnetic field in the entire region.

If there is only one or several magnetic domains in a substance, it is a permanent magnet. This substance can be naturally generated, such as a natural magnet (also known as magnetite), or it can be artificially manufactured, such as neodymium iron boron (the strongest permanent magnet). If there are many magnetic domains in a substance and there is no fixed arrangement between them, then it is a non permanent magnet. This substance does not have a clear net magnetic field when there is no external influence, but under the action of an external magnetic field, its internal structure can be temporarily or permanently changed to generate a net magnetic field. There are many types of this substance, such as soft iron, electric steel sheets, wire coils, etc.

So, why do two permanent or non permanent magnets attract or repel each other? This is because any object with a net magnetic field will generate an invisible and massless substance around it that can transmit power and energy, called a magnetic field. A magnetic field can be represented by some directional lines, called magnetic field lines. The magnetic field line starts from the north pole of the magnet and ends at the south pole of the magnet, forming a closed loop. The density of magnetic field lines represents the strength of the magnetic field, and the direction of magnetic field lines represents the direction of the magnetic field. The interaction between two magnets is actually the interaction between their magnetic field lines. When the homonymous poles of two magnets are close, their magnetic field lines will repel each other, causing the two magnets to also repel each other; When the synonyms of two magnets are extremely close, their magnetic field lines will attract each other, causing the two magnets to also attract each other. This is the principle we often refer to as' the same sex repels, the opposite sex attracts'.