Why is the magnetic force of a magnet "invisible"

What is magnetic force? Why is magnetic force "invisible"? People usually refer to magnetism as an attribute that attracts iron, nickel, cobalt, and other substances. It refers to the properties of the magnet itself that can guide paramagnetic substances, so its magnet is determined by the properties of the magnet. Magnetic force is an interaction. It can be said that the magnet itself has no magnetic force. This is the result of the interaction between two magnets, manifested as repulsion and attraction. So the polarity of a magnet is very strong. It cannot be said that the magnetic force at the poles of a magnet is high. When it comes to the properties of magnets, it is important to talk about magnetism. The interaction between magnets should be called magnetic force.

The magnetic force of a magnet is generated in three ways:

1、 Permanent magnet

Permanent magnets are commonly referred to as permanent magnets, and their professional name is neodymium magnets. Permanent magnets can continuously generate magnetic fields. There is a magnetic field in space that can generate magnetic force. A magnetic field is a special substance. The magnetic field around a magnet and the changing electric field can also generate a magnetic field, and the interaction between magnets is mediated by the magnetic field.

2、 Magnetism generated by electricity

If a straight metal wire passes through an electric current, a circular magnetic field will be generated in the space around the wire. The greater the current flowing through the wire, the stronger the magnetic field. When the magnetic field is circular, it will surround the wire. How to determine the direction of a magnetic field? It can be determined according to the "right hand rule": extend the right thumb and bend the other four fingers together towards the palm of the hand. At this point, the direction of the thumb is the direction of the current, while the direction of the other four fingers is the direction of the magnetic field. In fact, the magnetic field generated by this type of wire is similar to the effect of placing a small magnet with NS poles connected end-to-end around the wire.

3、 Flowing liquid metal

Capable of generating magnetic force on magnets, in addition to permanent magnets and electrogenerated magnets. Scientists have discovered that flowing metals can also generate strong magnetic fields in magnets. Experiments have shown that molten iron is poured into a sphere, which then rotates, generating a huge magnetic force. According to the speculation of the powerful magnet manufacturer, there may be a liquid iron core constantly rotating inside the Earth, forming a magnetic field. And it can change the strength of the Earth's magnetic field. Even the exchanges that have occurred in the history of the North and South have found a basis.