Magnetic fields have forces on various metal pairs, without exception. But there are three situations. In this way, metals are divided into three types: paramagnetic, inverse, and ferromagnetic.

1. Paramagnet: can be slightly attracted by a magnet.

2. Inverse magnet: it will be slightly repelled by the magnet.

3. Ferromagnet: Will be strongly attracted by magnets.

There are only three types of ferromagnets: iron, cobalt, and nickel. The rest are either paramagnetic or inverse magnets. There are also their alloys whose magnetic properties are close to ferromagnets in varying degrees of content.

Nickel-containing stainless steel can be attracted (strongly) by magnets. Nickel-free stainless steel (usually containing chromium) reacts weakly to this iron and is not easily noticeable. The latter has a higher hardness because it contains chromium. The former is commonly referred to as stainless iron.

Hang aluminum and copper with long thin wires and make them stand still. Use a magnet to approach aluminum or copper slowly laterally, and you can find that they will be slightly attracted or repelled. So they are paramagnet and inverse magnet respectively.

Magnet

Magnet is a kind of magnet.

Magnets can attract metals such as iron, nickel, cobalt, etc., commonly known as iron magnets. It can be divided into common permanent magnets and electromagnets that only have magnetism when energized. If the magnet is made into a rod or needle shape and suspended, it will naturally point to the south and north poles of the earth. Magnets are divided into large magnets and small magnets.

Large magnets Magnets have a wide range of uses. Electromagnets are used to make cranes for transporting steel. It becomes a magnet with strong magnetism after power on, so it can attract heavy steel. Just cut off the power when putting down the steel.

Small magnets Compared with large magnets, compasses are small and light, and their magnetism is much weaker. The function of the compass is not to attract iron, but to reflect the magnetic force of the earth.

The property of magnets to attract iron, cobalt, nickel and other substances is called magnetism. The areas with strong magnetism at both ends of the magnet are called magnetic poles, one end is the north pole (N pole) and the other end is the south pole (S pole). Experiments show that magnetic poles of the same sex repel each other, and magnetic poles of the opposite sex attract each other.

There are many primary magnets in iron with two opposite magnetic poles. When there is no external magnetic field, these primary magnets are arranged in disorder, their magnetism cancels each other out, and they do not show magnetism to the outside. When the iron is close to the magnet, the original magnets are arranged neatly under the action of the magnet, so that the end close to the magnet has a polarity opposite to that of the magnet and attracts each other. This shows that the iron can be magnetized by the magnet due to the existence of the original magnet. Metals such as copper and aluminum have no original magnet structure, so they cannot be attracted by magnets.